CHAPTER I SYNTHESIS AND ASSESSMENT OF ...shodhganga.inflibnet.ac.in/bitstream/10603/38350/7/07...Narender and Reddy 4 0 developed a new methodology by using BF 3- Et2O to synthesize

1

CHAPTER I

SYNTHESIS AND ASSESSMENT OF SUBSTITUENT EFFECT OF

SOME α, β - UNSATURATED KETONES

1.1 INTRODUCTION

The chemistry of α,β-unsaturated ketones has generated intensive scientific

studies throughout the world. Especially interest has been focused on the synthesis and

biodynamic activities of α,β-unsaturated ketones. The name “Chalcone” was given by

Kostanecki and Tambor1. These compounds are also known as benzalacetophenone or

benzylideneacetophenone. In chalcones, two aromatic rings are linked by an aliphatic

three carbon chain. The α ,β-unsaturated ketone bears a very good synthon so that

variety of novel heterocycles with good pharmaceutical profile can be designed. The

α ,β -unsaturated ketones are α ,β - unsaturated ketones containing the reactive

keto-ethylenic (–CO-CH=CH–) group. These are coloured compounds because of the

presence of the chromophore -CO-CH=CH- which depends in the presence of other

auxochromes.

The α,β-unsaturated ketones are the precursors in the biosynthesis of

anthocyanins and flavones. The enzymatic cyclization of the 6’-hydroxy chalcones leads

to the formation of large number of flavonoid groups including flavones, flavonols,

dihydroflavonols, aurones and isoflavones2. The α,β-unsaturated ketones are used to

synthesize several derivatives like cyanopyridines, pyrazolines, isoxazoles and

pyrimidines having different heterocyclic ring systems3-6. They are also very important

as a Michael acceptor in organic syntheses7.

2

The α,β-unsaturated ketones can be synthesized in laboratory by

Claisen-Schmidt condensation of acetophenones with aromatic aldehydes. The

chemistry of α,β-unsaturated ketone has been recognized as a significant field of study,

the phenomenal growth of publications in this area is undoubtedly a reflection of the

interest in this field throughout the world.

Since 1990’s chemists are paying much more interest in the application of

solvent free synthetic methods8 in organic reactions like Claisen-Schmidt9,

Knovenagel10, Aldol11 and Crossed-Aldol12 employed for the synthesis of carbonyl

compounds due to the operational simplicity, easier work-up, better yield and

eco-friendly nature.

VARIOUS CONDENSING AGENTS USED IN SYNTHESIS OF α,β-UNSATURATED

KETONES

1. Alkali

Alkali has been used as the condensing agent for the synthesis of

α,β-unsaturated ketones. It is used as an aqueous solution of suitable concentration

viz., 30 %, 40 %, 50 % and 70 %.

2. Hydrochloric Acid

Dry hydrogen chloride gas in a suitable solvent like ethylacetate at 0o

C was

used as a condensing agent in a few syntheses of α,β-unsaturated ketones from

aromatic ketones. Methanolic solution of dry hydrogen chloride gas at 0o

C was also

used by Lyle, Paradis13 and Marathey14.

3. Other Condensing Agents

Raval and Shah15 used phosphorous oxychloride as a condensing agent to

synthesize α,β-unsaturated ketones. Szell and Sipos16 condensed 2-hydroxy-5-nitro-

acetophenone with benzaldehyde using anhydrous AlCl3. Kuroda, Matsukuma and

Nakasmura17 obtained α,β-unsaturated ketones by condensing acetophenone derived

3

from anisole and other polymethoxy benzenes with some methoxyaldehydes in the

presence of anhydrous aluminum chloride.

Besides the above, other condensing agents used in synthesis of α,β-

unsaturated ketones are given below:

(1) Amino acid18

(2) Aqueous solution of borax19

(3) Perchloric acid 20

(4) Piperidine 21

(5) Boron trifloride 22

(6) Alkali metal alkoxide 23

(7) Magnesium tert-butoxide 24

(8) Organocadmium compound 25

SYNTHETIC METHODS OF PREPARATION OF α,β -UNSATURATED KETONES

CLAISEN-SCHMIDT REACTION

A variety of methods are available for the synthesis of α,β-unsaturated

ketones, the most convenient method is the one that involves the Claisen-Schmidt

condensation of equimolar quantities of a substituted acetophenone with substituted

a r o m a t i c aldehydes in the presence of aqueous alcoholic alkali (1)26-33. In the

Claisen-Schmidt reaction, the concentration of alkali used, usually ranges between10

and 60% 23,34. The reaction is carried out at about 50o

C for 12-15 hours or at room

temperature for one week. Under these conditions, the Cannizzarro reaction 35 also

takes place and thereby decreases the yield of the desired product. To avoid the

disproportionation of aldehyde in the above reaction, the use of benzylidene-

diacetate in place of aldehyde has been recommended 36.

4

CH3

O

O

O

R

R'

:OH- -H2O

H

1

ALDOL-CONDENSATION

M. R. Jayapal et.al.,37 synthesized some 2,6-dihydroxy substituted α,β-

unsaturated ketones by aldol condensation method using SOCl2/EtOH as solvent. The

structures of these synthesized compounds were confirmed by IR, Mass spectroscopy

and elemental analysis.

H3C O

OH

OH

OH

SOCl2

EtOH

O

HO

OH

R

R

R= 4-Cl, 3-OH, 4-OH, 4-NO22

FRIEDEL-CRAFTS ACYLATION

Besides the Claisen-Schmidt reaction, Bohm 38 synthesized α,β-unsaturated

ketones by direct Friedel-Crafts acylation of phenol. In this approach phenol becomes

the A-ring while the acylating agent provides both the B-ring carbons and the

three carbon bridge to form C6-C3-C6 unit. Friedel-Crafts acylation of 2, 4-dimethyl-

5

1,3,5-triolbenzene with cinnamoyl chloride gave 2’,4’,6’-trihydroxy-3’,5’-dimethyl

chalcone(3).

CH3

OH

OH

H3C

HO

O

Cl

Anhyd. AlCl3

O

CH3

H3C

OHHO

OH

3

An efficient and clean synthesis of 1,3-diaryl-2-propenones had been carried out

by Claisen Schmidt condensation reaction of aryl methyl ketones with a series of

aromatic aldehydes at room temperature in the presence of the catalyst silico tungstic

acid (4)39 (STA). This method provides an ecofriendly, chemoselective, efficient and

green synthesis of 1,3-diaryl-2-propenones in excellent yields.

O

H

R2

STA (10mol%) Stirred at r.t.

R1 = H, 2-OH, 4-Cl

R2 = H, 4-Cl, 2-Cl, 3-NO2, 4-OCH3, 3,4-(OCH3)2

O

R2

CH3

OR1

R1

4

6

SYNTHESIS OF α,β-UNSATURATED KETONE USING BORONTRIFLUORIDE-

ETHERATE

Narender and Reddy 4 0 developed a new methodology by using BF3- Et2O to

synthesize several substituted α,β-unsaturated ketones. The advantages of this

method over the existing methods are high yields, simple work-up, short duration,

absence of side reactions, and easier separation of the products. This is a solvent-

free reactions and also applicable for reactions involving liquid reactants which are

base sensitive functional groups such as esters and amides.

A condensation reaction between O-acylated or N-acylated acetophenone

and the respective aromatic aldehyde produced O-acylated (5) or N-acylated α,β-

unsaturated ketones (6) in high yields by using BF3-Et2O as catalyst.

O

CH3

O

+

OH

O

H

BF3-Et2O, Dioxane 87%

90min

O

O

OH

H3C O

H3C O

5

7

HN

CH3

O

+

OCH3

O

H

BF3-Et2O, Dioxane 93%

90min

HN

O

OCH3

H3C O

H3C O

6

Carthamin (7), a red pigment was first obtained as red needles with green

iridescence using pyridine solvent from the flowers of cartharmus tinctoria (safflower) by

Kmetaka and Perkin 41 and this was the first known example of α,β-unsaturated

ketone in nature.

OOH

OH OH

OGC

O

7

It isomerizes to a yellow compound isocarthamin (8) on treatment with dil. HCl

as reported by Kuroda 42.

8

OOH

OH OH

OGC

HO

8

Venkatraman and Nagrajan43 prepared bis-α,β-unsaturated ketone (9) and (10)

from dihydroxy-diacetylbenzene and anisaldehydes using alkali.

C

O

C CCCC

OH

H H

H

OH OHOCH3 OCH3

9

C

O

C CCCC

OH

H H

H

OH OH

H3CO OCH3

10

Several hydroxy-nitro α,β-unsaturated ketones were prepared using dry

hydrogen chloride gas44-46. Onoda and Sasaki47 used hydrochloric acid to

9

synthesize hydroxy-nitro α,β-unsaturated ketone (11) from 2-hydroxy-5-

nitroacetophenone and p- anisaldehyde.

O

OCH3

OH

NO2

11

The α,β-unsaturated ketones (12) were prepared by reaction of benzaldehyde

with phosphonate carbanion derived from diethyl phenacyl phosphonate48-51.

O

OO

PC2H5O

OC2H5

O

H

12

Several workers52-54 prepared s o m e α,β-unsaturated ketones from saturated

ketones and aromatic aldehyde in ethanol as energy transfer medium.

10

Mistry and Desai 55 synthesized α,β-unsaturated ketone (13) using microwave

technique.

C

O

C CH3CO

H

H

Cl

Cl

13

Naik and Naik56 synthesized α,β-unsaturated ketone derivative from 2-hydroxy-

3-bromo-5-ethyl acetophenone (14).

C2H5

OH

H3C O

HO

Br C2H5

O

R

Br

R.CHO

Aq.KOH, 40%

14

SOLVENT FREE METHOD

A series of α, β-unsaturated ketones were synthesized by Crossed-Aldol

condensation reaction, from 6-methoxy-2-naphthyl ketones and substituted

benzaldehydes, under eco-friendly solvent free conditions using silica-sulphuric acid as

catalyst. The yields of ketones (15) were more than 90% and the catalyst was reusable

for further reaction. There was no appreciable decrease in the yield of product and the

activity of the catalyst57-59.

11

CH3

O

H3CO

+

H

O

X

C

O

H3CO

C

X

SiO2 - H2SO4

Solvent free 80oC

HH

15

Sixteen substituted styryl 3,4-dichlorophenyl ketones (16) were synthesized using

eco-friendly benign stereoselective Crossed-Aldol condensation. They were

characterized by their Infrared, NMR and Mass spectra57.

Cl

CH3

O

+ O

H

NaOH, CTABr

Solvent free

Cl

O

CH

HC

16

Cl

X

Cl

X

12

MICROWAVE IRRADIATION METHOD

Over the years various innovative methods have been devised to speed up the

chemical reactions. In these environmentally conscious days the development of

technology is directed towards environmentally sound and ecofriendly methods. The

usage of microwave energy to accelerate the organic reactions is of increasing interest

and offers several advantages over conventional heating techniques 60.

Synthesis of the

molecules which normally requires a long time can be achieved conveniently and

rapidly in microwave oven. Less reaction time, easy work up and cleaner products are

the major advantages of microwave irradiation technique. Furthermore the reactions

can be carried out under solvent free conditions which holds a strategic position as the

solvents are often very toxic, expensive and sometimes hazardous. Solvent free

condition is especially suitable for microwave technique. Thus the use of microwave

energy for the synthesis of organic compounds forms a part of green chemistry.

The air-dried paste of 2’-hydroxyacetophenone , benzaldehyde and anhydrous

K2CO3 was subjected to microwave irradiation by Srivastava61 for 3-5 minutes

to produce 2’-hydroxy α,β-unsaturated ketones (17). This reaction gave a cleaner

product with a high yield (80-90%).

CH3O

OH

OH

OH O

anhyd. K2CO3

MW. 3-5 min

17

Recently Vanangamudi et.al., have synthesized twelve substituted

2-pyrrolyl-α,β-unsaturated ketones 62 (18) using Fly-ash: H2SO4 as catalyst, twelve

13

substituted 5-chloro-2-thienyl-α,β-unsaturated ketones63 (19) and twelve substituted

4-nitrophenyl-α,β-unsaturated ketones64 (20) using Silica-H2SO4 as catalysts under

eco-friendly microwave irradiation methods.

N

CH3

O

O

H

X

Fly-ash:H2SO4

MWN

O

X= H, 2-Cl, 3-Cl, 4-Cl, 3-F, 4-F, 2-OCH3, 3-OCH3, 4-OCH3, 4-CH3,

2-NO2, 3-NO2

H

HX

18

O

H

X

Silica-H2SO4

MW

X= H, 3-Br, 3-Cl, 2-F, 4-F, 4-OH, 2-OCH3, 2-CH3, 4-CH3, 2-NO2, 4-NO2, 3-OPh

O

X

SCl

O

CH3

SCl

19

14

O

H

X

Silica-H2SO4

MW

X= H, 3-Br, 4-Br,3-Cl, 4-Cl, 4-F, 2-OCH3, 4-OCH3, 4-CH3, 2-NO2, 3-NO2, 4-NO2

CH3

O

O2N

O

O2N

X

20

Song et.al., 65 synthesized some α,β-unsaturated ketone derivatives and

introduced them as a side chain unit in the backbone of polyimide for photo-alignment

layers. The rate of photoreaction was followed by the disappearance of the C=C and

C=O bond in the α,β-unsaturated ketone moiety using UV–visible spectroscopy. They

reported the effect of the length of alkyl chain in α,β-unsaturated ketone derivatives and

found that the alignment properties are very much dependent on the chain length.

Some trans-ferrocenyl α,β-unsaturated ketones undergoes bromination reactions

in the presence of cyclodextrin gave erythro-dibromide derivatives66. But in the absence

of cyclodextrin, the analogous ferrocenyl chalcones does not undergo bromination at

room temperature. This complexation does not induce any variation in the bromination

pattern and the ferrocenyl moiety is not attacked in the reaction. These observations

have been accounted for in terms of guest–host interaction patterns. The formation of

complex and dibromination product has been studied and confirmed by elemental

analyses, UV–Vis, IR, 1H-NMR, 13C-NMR, and electrochemical methods.

Three 2′-hydroxy chalcone derivatives were electrochemically reduced to the

radical anion by a reversible one-electron transfer followed by a chemical dimerization

15

reaction. Under suitable conditions of the medium, the one-electron reduction produced

very well resolved cyclic voltammograms due to the formation of the radical anion. From

the cyclic voltammetric technique, the generation of the radical anion and its stability

were studied 67.

Sharma et.al.,68 synthesized five substituted α,β-unsaturated ketones by

Claisen Schmidt condensation of substituted acetophenones and substituted

benzaldehydes in the presence of a base by conventional and microwave assisted

methods. They have been characterized by spectral data and evaluated as non azo

dyes for dyeing of silk fabric using metallic and natural mordants and their combination.

Optimization of different dyeing conditions as well as washing and light fastness of

some selected dyed samples has also been examined.

Some chalcone derivatives69 such as (2E)-1-(Substituted-Methylthiophene-2-yl)-

3-(pyridin-substituted-yl)prop-2-en-1-ones were titrated with tetrabutylammonium

hydroxide (TBAH) in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol,

N,N-dimethylformamide and acetonitrile), using potentiometric method. The half

neutralization potential values and the corresponding pKa values were determined.

Several disubstituted ferrocenyl chalcones were shown to possess good

electrochemical sensors70 for calcium and barium ions in CH3CN.

The X-ray crystal study has also been carried out with α,β-unsaturated ketones.

Pyridine and hydroxyl chalcones had been reported to undergo [2+2] photodimerization

reactions71. The mutual orientations of adjacent molecules in the crystals were analyzed

and the results were compared with known photoactive crystals. The single-crystal-to-

single-crystal photodimerization study of pyridine analog chalcones possessed the

mixed crystals containing both the substrate and the product. The role of hydrogen

16

bonds in the [2+2] photodimerization in the case of the hydroxy derivatives of chlcone

had also been explained.

Two ferrocenyl chalcones containing the anthracenyl group, Fc–COCH=CH–Anth

(Fc–Anth) and Anth–COCH=CH–Fc (Anth–Fc)72, were prepared by solvent-free aldol

condensation using acetylferrocene /9-anthraldehyde and 9-acetylanthracene /

ferrocene carboxaldehyde, respectively. The X-ray crystal structure analyses showed

that these products crystallize as racemic mixtures. High torsion angles between the

anthracenyl group and the enone linkage were observed for Fc–Anth (55.7(4)˚) and

Anth–Fc (74.9(4)˚) and the enone linkage has different conformations for Fc–Anth

(s-cis) and Anth–Fc (s-trans). The cyclic and differential pulse voltammetry analyses

showed one reversible cycle corresponding to the Fc/Fc+ process (E1/2 = 0.402 V for

Fc–Anth and 0.277 V for Anth–Fc), and one irreversible peak corresponding to the

oxidation of the anthracenyl group (Epa2 = 1.073 V for Fc–Anth and 1.153 V for

Anth–Fc). The fluorescence properties of the anthracenyl group were quenched in these

chalcones, possibly by the ferrocenyl group.

Several 1-(1,3-benzodioxol-5-yl)-3-(aryl)-prop-2-en-1-ones were prepared by the

aldol condensation of 1-(1,3-benzodioxol-5-yl)ethanones and aryl aldehydes. Base

catalyzed condensation of 1-(1,3-benzodioxol-5-yl)-3-(aryl)prop-2-en-1-ones with ethyl

acetoacetate yields corresponding ethyl 4-(1,3-benzodioxol-5-yl)-6-(aryl)-2-oxocyclohex-

3-ene-1-carboxylates and they are characterized by single crystal X-ray studies, IR,

1H-NMR and LCMS mass spectral analysis73.

Zhang et.al.,74 characterized some chlcones by electrospray ionization tandem

mass spectrometry. Several ionization modes were evaluated, including protonation,

deprotonation and metal complexation, with metal complexation being the most

efficient. Collision-activated dissociation (CAD) was used to characterize the structures,

17

and losses commonly observed include H2, H2O, CO and CO2, in addition to methyl

radicals for the methoxy-containing α,β-unsaturated ketones. CAD of the metal

complexes, especially [CoII (α,β-unsaturated ketone-H) 2,2′-bipyridine]+, allowed the

most effective differentiation of the isomeric α,β-unsaturated ketones with several

diagnostic fragment ions appearing upon activation of the metal complexes.

MSn experiments were performed to support identification of some fragment ions and to

verify the proposed fragmentation pathways. In several cases, MSn indicated that

specific neutral losses occurred by stepwise pathways, such as the neutral loss of

CH3 and HCO, or CH4 and CO, in addition to CO2.

The structural and optical properties of 4-bromo-1-naphthyl α,β-unsaturated

ketones (BNC) have been studied by using quantum chemical methods75. The density

functional theory (DFT) and the singly excited configuration interaction (CIS) methods

were employed to optimize the ground and excited state geometries of unsubstituted

and substituted BNC with different electron withdrawing and donating groups in both

gas and solvent phases. Based on the ground and excited state geometries, the

absorption and emission spectra of BNC molecules were calculated using the time-

dependent density functional theory (TDDFT) method. The solvent phase calculations

were performed using the polarizable continuum model (PCM). The geometrical

parameters, vibrational frequencies, and relative stability of cis- and trans-isomers of

unsubstituted and substituted BNC molecules have been studied. The results from the

TDDFT calculations reveal that the substitution of electron withdrawing and electron

donating groups affects the absorption and emission spectra of BNC.

Asiri et.al.,76 synthesized mono and bis-chlcones as thin films from

3-acetyl-2,5-dimethylthiophene and N,N-dimethylbenzaldehyde / terephthalaldehyde by

thermal evaporation methods. These α,β-unsaturated ketones are characterized by

18

elemental analysis, IR, 1H NMR, 13C NMR and GC–MS spectral analysis. The optical

property of these α,β-unsaturated ketones from optical constant values as a function of

photon energy were measured and reported that the absorption coefficient of mono

and bis-α,β-unsaturated ketones varies with increasing photon energy.

The intramolecular charge transfer (ICT) of an efficient π-conjugated potential

push–pull NLO chromophore, 1-(4-methoxyphenyl)-3-(3,4-dimethoxyphenyl)-2-propen-

1-one to a strong electron acceptor group through the π -conjugated bridge has been

carried out from their vibrational spectra77. The NIR FT-Raman and FT-IR spectra

supported by the density functional theory (DFT) quantum chemical computations have

been employed to analyze the effects of intramolecular charge transfer on the

geometries and the vibrational modes contributing to the linear electro-optic effect of the

organic NLO material. The calculated first hyperpolarizability of DMMC is 6.650 x10-30

esu, which is 25 times that of urea. The simultaneous IR and Raman activation of the

phenyl ring modes of m(C=C/C–C) mode, ring C=C stretching modes, in-plane

deformation modes and the umbrella mode of methyl groups also provide evidences for

the charge transfer interaction between the donors and the acceptor group through the

π-system. Vibrational analysis indicates the electronic effects such as induction and

back-donation on the methyl hydrogen atoms causing the lowering of stretching

wavenumbers have also been analyzed in detail. The planar conformations would give

an enhanced NLO activity where as any deviations from planarity would decrease the

mobility of electrons within the π -conjugated molecular system, resulting a reduction in

NLO activity.

Some substituted 4-X-chlcones were synthesized from acetophenone and

p-substituted(X) benzaldehydes (X = H, OH, N(CH3)2, F, Cl, OCH3, NH2 and CH3) . The

structure, rate of formation and trans s-cis ↔ trans s-trans conformational equilibrium of

19

these 4-X-chalcones were studied78. The rate of formation of 4-X-chalcones varies with

the substituent in the order N(CH3)2 = NH2 > OH = OCH3 > F > CH3 > Cl = H. Although

transs-cis conformers are the most stable one and transs-trans forms also show acceptable

thermodynamic stability. In the transs-cis ↔ transs-trans equilibrium, the percentages of the

transs-cis conformer at 298K ranged between 37% and 82% approximately.

Generally, the most of studies covered the various methods of synthesizing

α,β-unsaturated ketones, structural conformations, existence of isomeric forms,

reduction potentials, rate of the formation, optical linear activity, crystal studies of

α,β-unsaturated ketones and etc.,

In addition to these studies, Alston et.al.,79 studied the effect of substituents of

α,β-unsaturated ketones from their reduction potential values. The reduction potentials

of a set of 23 monosubstituted and 7 disubstituted benzalacetophenones

(α,β-unsaturated ketones) are linearly correlated considerably better with the σπ values

of van Bekkum, Verkade, and Webster than with Hammett σ. Groups were found to

exert the same effect upon the reduction potential irrespective of which ring they are

located on. The data for monosubstituted benzalacetophenones can be used to predict

the reduction potentials of disubstituted derivatives with good accuracy.

In addition, a linear relationship between the half-wave reduction potentials of

α,β-unsaturated carbonyl compounds R–CH=CH–CO-X and the Hammett σp values

were studied80. A linear relationship is also observed for the LUMO’s energy values, the

absolute chemical hardness η, the chemical potential µ, the electrophilicity power ω, or

the polarization of the ethylenic double bond with the Hammett σp values.

Also the absorption maximum of the following α,β-unsaturated ketones (21) was

measured and these values were correlated linearly with Hammett substituent

20

cionstants81. A linear relationship was observed between the log of rate constants and

Hammett reaction constants with σ > 0.98.

O

RX

H

H

21

where,

R = H, m-NO2, p-Br and p-Phenyl

X = H, p-CH3, p-OCH3, p-Cl and p-NO2

Thirunarayanan et.al., have improved the study of substituent effects of

α,β-unsaturated ketones by regression analysis with Hammett substituent constants.

They had reported the study of substituent effects with respect to some substituted

α,β-unsaturated ketones such as ω-bromo-2-naphthyl-α,β-unsaturated ketones82,

2-[(E)-3-Substituted Phenylacryloyl] Cyclopentanones83, 5-methyl-2-furyl-

α,β-unsaturated ketones84 and 9H-fluorenyl α,β-unsaturated ketones85.

Also Vanangamudi et.al., reported similar studies on substitued 1-naphthyl

α,β-unsaturated ketones86, 2-hydroxy-1-naphthyl α,β-unsaturated ketones87 and

2-phenothiazenyl α,β-unsaturated ketones88. Recently, the effects of substituents on

styryl moiety using regression analysis of 2-pyrrolyl α,β-unsaturated ketones62, 5-chloro-

2-thienyl α,β-unsaturated ketones63 and 4-nitrophenyl α,β-unsaturated ketones64 have

been studied.

21

1.1.1 UV Spectral Study

The spectra arising out of electronic transition in molecules are termed as

ultraviolet visible spectra89-90. These transitions arise due to the existence of discrete

energy levels in molecules as shown in (22).

σ*

π*

n

π

σ

σ-σ * n-σ* π-π* n-π*

Electronic transition in molecules (22)

Some of the transitions shown above are exhibited by α, β -unsaturated

carbonyl compounds exists in s-cis and s-trans forms. Lutz et.al.,90 have clearly

indicated that a significant differences exists in the spectra of cis- and trans-forms.

These forms (23) are thought to consist of two differently non-conjugated chromophoric

systems, namely benzoyl and cinnamoyl91-92 groups. Hence one might expect two

independent characteristic bands for these in these α,β-unsaturated ketones.

22

HC

HC CH

O CH3

CH

HCO

CH

CH3

s-cis s-trans

HC

HC CH

OH CH2

CH

HCHO

CH

CH2

s-cis s-trans

23

The study of Szmant and Basso93 on the absorption spectra of α,β-unsaturated

ketones shows that they exhibit long wavelength band of trans-α,β-unsaturated ketones

(298 nm in hydrocarbon and 312 nm in alcoholic solution) and short wave length band

at 225-260nm. The characteristic band lies at 286 nm. Thus it is evident that the

absorption in α, β-unsaturated carbonyl compounds (α,β-unsaturated ketones) is due to

the transmission of electronic charges as shown in (24) and not due to any isolated

system.

CH-CH=C CH=CH-C

OO

24

Although, far more attention has been paid to study and interpret the ultraviolet

absorption spectra of α,β-unsaturated ketones, no significant work has been carried out

in this direction for α,β-unsaturated ketones involving 2-thiophene styryl ketones.

Latha94 investigated the effect of substituents in thiophene chalcones with liquid phase

23

UV-spectral data. They find very poor correlation with σ and σ+ constants with maximum

absorptions of these α,β-unsaturated ketones using ethanol and hexane as solvents.

Effect of dielectric constant

The UV absorption spectra for all the synthesized compounds were recorded in

ethanol, hexane and six different ethanol-water mixtures. The absorption in hexane is

due to the electronic transition from a non-solvated ground state to a non-solvated

excited state. The difference in absorption maxima between in hexane and those in

alcohol water mixture is a direct mixture of the excited state stabilization energy of the

styryl ketones under investigation various alcohol water mixture.

∆λ max = λ max Ethanol-Water- λ max hexane … (1)

To study the effect of polarity and the UV absorption data, the frequency shift for

the styryl ketones were plotted against ε, 1/ε and f(ε) here f(ε) is the Kirkwood95

function of dielectric constant, i.e., (ε) is equal to ε -1/2ε + 1.

In all the plots provides perfect linearity between the stabilization energy and

dielectric constant of the alcohol-water mixture and it establishing the fact that the

stabilization energy is increased by solvation of excited state, as there is perfect

correlation between the stabilization energy of the excited state and dielectric constant

of all the medium, it was thought of great interest to see if any correlation exist

between stabilization energy of excited state and dielectric constant of the medium by

varying the alcohol themselves. Hence the UV spectra of the substituted 2-thiophene

styryl ketones involving unsubstituted in benzene ring were recorded in hexane and in

various alcohols of varying dielectric constants such as methanol, ethanol, propan-2-ol,

butan-2-ol, benzyl alcohol and tertiary butyl alcohol as mentioned earlier.

The difference in absorption maxima between those in hexane and those in

various alcohols is direct measure of excited state stabilization energy of 2-thiophene

styryl ketones under investigation.

24

Solvent effect is best interpreted in terms of the following properties.

1. The dielectric behavior,

2. The ability of the medium to solvate and

3. The ability of protic solvent to form hydrogen bond with negative end of the dipole.

The Kirkwood 95 function of the dielectric constant f(ε) = ε – 1/2ε + 1 is suitable

measures of a while b and c together are governed mainly by the polar effect of alkyl

group of alcohol suitably measured by Taft 96 polar substituent constant σ*. The solvent

parameters employed are compiled in table.

Since the excited state in all the 2-thiophene styryl ketones involve charge

separation one might expect that the excited state will be stabilized by increasing the

polarity of alcohols. Hence it was attempted to see if any correlation extremely poor.

The attempt was improved the correlation are employing σ values. The polar

substituent constants of alcohols in these cases also the correlation was miserable

for 2-thiophene styryl ketones so that the log ∆λ max were calculated making use

of above equation.

This equation is also called linear solvation energy relationship (LSER), here α, β

and π* are solvate chromic parameters and a, b and s are Solvatochromic coefficient, π*

is the solvent polarity which is a measure of the ability of solvent to stabilize a charge or

a dipole by virtue of its dielectric effect. .

The variable α is a measure of the solvent hydrogen bond donor acidity and

describes the ability of a solvent to donate a proton in solvent to solute hydrogen bond.

The variable β is the measure of solvent to solute hydrogen bond. The variable β is the

measure of solvent hydrogen bond accepter basicity and describes the ability of accept

a proton, a solute to solvent hydrogen bond. The multiple linear regression analysis of

the spectroscopic data in eight different solvents is carried out using the equation (2).

25

Log λ max = - 0.0961π*- 0.0182α + 0.03β + 2.50 … (2)

r = 0.5201; S.D=0.015; n= 8.

In π → π* transition of substituted 2-thiophene styryl ketones, the negative sign

of the coefficient σ and µ indicates a bathochromic shift with both increasing solvent

polarity and solvent hydrogen bond donor acidity. The positive sign of coefficient

β indicate hypsochromic shift with increasing solvent hydrogen bond acceptor basicity.

1.1. 2 IR Spaectral Study

Infrared spectroscopy is a powerful tool technique for the quantitative and

qualitative study of natural and synthetic molecules. A great deal of work has been

devoted to the reactivity of α, β-unsaturated carbonyl compounds particularly, for the

theoretical study of substituent effects on enol97 tautomerism.

CH2

CH2

s-cis s-trans

25

26

H3C

H3C

O

RH3C

H3C

R

O

s-ciss-trans

O CH3

CH3

O

s-cis s-trans

OH CH2

CH2

OH

s-cis s-trans

26

Slightly different, but yet related to the above phenomenon occurs in flexible

aromatic molecules like α, β-unsaturated ketones where s-cis and s-trans isomers exist

as illustrated in (25) and (26). The existence of such isomers is confirmed by infrared

spectroscopy98-99.

Normally the carbonyl stretching band in the infrared spectra of carbonyl

compounds100-101 appears at 1850-1650cm-1. This range depends primarily on the force

constant of C=O bond and only to a lesser extent on the mass attached to the carbon atom.

The force constant of C=O is evaluated by the distribution of electrons in and around the

linkage102-103. The influence of small changes in molecular structure on the C=O frequency

is discussed with the following terms.

27

· Mesomeric effect associated with the electron mobility acting along the system of

conjugated bonds.

· Inductive effect determined by nuclear charges acting along the bonds.

· Electrical field effects associated with nuclear charges acting on the C=O bond

across space.

· Steric effect, especially those associated with vander Waals repulsions between

vicinal non-bonded atoms and

· Hydrogen bonding.

Several investigations have shown that the infrared frequency shifts of “mass

insensitive” in vibrations can be correlated with reactivities such as inductive and

mesomeric effects104 and other important physical properties105-107. The influence of

polar effects on infrared frequencies is largely independent of mass or combination

effects. The frequency is affected by inductive and mesomeric effects of substituents. In

addition, there are numerous examples of correlation of carbonyl stretching frequencies

with Hammett substituent constants for series in which there is little change of carbonyl

bond angles or presumably of bond force constants with substituents.

Jones, Forbes and Mueller102 have investigated the spectra of substituted

acetophenones with substituents at ortho-, meta- and para- positions. Carbon

tetrachloride was used as a solvent for recording the position of the absorption maxima,

the integrated absorption intensities and the widths of the C=O stretching bands. In the

para- substituted acetophenones, the lowest frequency was observed for the amino

group and the highest observed for the para-nitro group. These νC=O values were

correlated with Hammett reactivity σm constants.

28

The carbonyl frequencies of several ortho-, meta- and para- substituted

acetophenones were measured in CCl4 solution by Soloway et al.,108 and Kruger109 .

These frequencies were correlated with the electrophilic substituent constants

σ+ through the following expression (3).

νC = O (cm-1) = 11.53σ+ +1691.5 ...(3)

(r = 0.988, s = 1.2, n = 27)

The frequencies of carbonyl stretching bands of o-substituents follow this

correlation, assuming σ0+, σp

+ while those oriented cis to the substituent generally do

not. Deviations of νC=O group from this correlation were interpreted in terms of dipole

interactions, steric hindrance to planarity, intramolecular hydrogen bonding and

non-additivity of σ+ values for some combination of substituents. The carbonyl

frequencies of meta- and para- monosubstituted acetophenones are correlated with the

polar (σI)98 and resonance (σR

+) components of σ+ (σ+ = σI + σR) by the expression (4):

νC=O(cm-1) = 15.66σI+10.99σR + 1689.8 ...(4)

(r = 0.981, s = 0.9, n = 13)

The transmission co-efficients of σI and σR+ indicate that the carbonyl frequency

was more susceptible to the polar effect than that to resonance effect in

acetophenones. In ω-substituted acetophenones no precise correlation with polar

constants were observed.

A statistical evaluation of the empirical linear correlations of infrared group

frequencies and band intensities in aliphatic and benzene derivatives with substituent

constants have been carried out110.

The correlation of frequencies with substituent constants generally gave low

standard deviation and acceptable correlation co-efficients and may thus be employed

for the estimation of substituent constants. The correlations of band intensities with

29

substituent constants show an interesting trend of the sign and magnitude of the slopes

(ρ values) with the electrical property of the bond or group involved in the vibration. The

value decreases with the increasing electron withdrawing power of the group.

Also investigation on the C=O frequencies of acetophenones111 and

ω-naphthacyl benzoates112 were known and there have been no systematic attempt

was made to correlate carbonyl frequencies with substituent constants. However, the

carbonyl stretching frequencies of substituted benzophenones107 were correlated with

the corresponding half wave potentials.

The infrared spectra of several trans-3-phenoxymethylenephthalides (27),

cis-3-phenoxymethylenephthalides (28) and trans-3-phenylthiomethylenephthalide (29)

in the region of the C=O and C=C stretching vibrations were investigated by Perjessy and

Lacova113. The carbonyl stretching frequencies of trans-3-arylmethylenephthalides114 were

shifted to lower values by 6-8 cm-1, when compared with those for (27) and (29). This

shifts indicated a reduction in the C=O bond polarity in compound (27) and (28), relative

to that in 3-phenylmethylenephthalides, which is a consequence of damped

transmission of electronic effects of substituents through the sulphur or oxygen atom.

The carbonyl stretching bond frequencies of cis-3-phenoxymethylenephthalides (28)

were shifted to 5-8 cm-1 lower than that for the corresponding trans isomers. In these

three series of compounds known, the existence of linear relation between C=O

stretching frequency and σ constants of substituents were quite pronounced. It was inferred

that the introduction of oxygen or sulphur bridges into the structure of trans-3-arylmethylen

phthalides reduced the transmission of electronic effects of substituents.

30

C

O

O

C

HO

YX

27

O H

O

O

Y

X

28

C

O

C

HS

XY

O

29

Marcus and co-workers115 have observed better transmission of electronic effects

through oxygen than through sulphur indicating that these atoms in a conjugated

system play predominantly a role of electron donors, oxygen being more efficient than

sulphur.

Carbonyl stretching frequencies in the case of para- and meta- substituted

N,N-dimethylbenzamide (30) and cinnamides (31) were measured in carbon

tetrachloride116. The results were correlated with the substituent constants of Swain and

Lupton117 and with the carbonyl π-bond orders and the oxygen π-electron densities

obtained from H.M.O calculations. In substituted N,N-dimethylbenzamide (30) and

cinnamides (31) there was cross-conjugation of carbonyl and nitrogen (the amide

resonance), which will reduce the substituent effect on the carbonyl stretching vibration

due to the non-planar arrangement of the amide plane and the benzene ring. The

rotational energy barrier (ΔG) of the amide (which will be related to νC-N and νC=O)

was correlated with carbonyl frequency which shows a fair correlation in both

benzamide and cinnamide series.

31

N

O

CH3

CH3

30

H

H

N

O

CH3

CH3

31

Hays and Timmons118, investigated the infrared spectra of a number of styryl

ketones, which could exist in one or more conformations and concentrated by the

measurements in the region of the C=O and C=C fundamentals and first overtone bands.

The conformations could be planar s-trans, planar s-cis or non-planar. In butadiene, two

isomers, s-cis and s-trans were possible, but s-trans isomer was more favorable. Butadiene

derivatives do not exist in s-trans and may be s-cis or non-polar. Aston and his

associates119 evaluated that the energy difference between the two-butadiene isomers

were 2.3 Kcal.mole-1, the s-trans form being more stable and the C-C rotational energy

barrier was 2.6 Kcal mole-1.

Cinnamaldehyde has only one form of s-trans due to the absence of steric

effects. When the aldehydic hydrogen is replaced by a methyl group, the s-trans

conformer predominates together with either s-cis or a non-polar conformer. The s-trans

isomers have higher infrared absorption intensities of the C=O group than s-cis

conformer of same molecule.

When the aldehydic hydrogen was replaced by groups of increased size, the

energy separation was reduced and the proportion of the s-trans conformer becomes

less, so that the s-trans conformer no longer predominates which indicated that the

energy of the conformer was higher than that of the s-cis conformer. In phenyl styryl

ketones, the predominant conformer was probably the s-cis. This may be possible due

to repulsion of the two phenyl groups in s-trans form. In the molecules where both

32

carbonyl conformers were present the electrical unharmonicity of the s-cis is about twice

as that in s-trans due to the increased polarity of the s-cis form.

The intensity associated with the s-cis conformer was much greater than that

associated with the s-trans conformer. In compounds consisting of a mixture of both

conformers, one would expect the two carbonyl absorption bands to be accompanied by

the two C=C bands. Because of the close proximity of the C=C bands and of the much

greater intensity of the s-cis band, one could expect the C=C s-trans band to appear as

an inflexion on the C=C s-cis band at a higher wave number.

There were four possible explanations to account for the attainment of the

various forms

· Low energy required for free rotation about C-C bond

· Small energy difference between the various forms

· Steric hindrance and

· Field effect between the C=O and C=C groups

From the infrared spectra of some Α,β-unsaturated ketones derived from

3-chloro-2-hydroxy, 3-chloro-4-hydroxy and 5-chloro-2-hydroxy acetophenones120 some

interesting generalization on some structure spectra correlation with regard to carbonyl

and ethylenic absorption was well known that whenever there was an increased

opportunity for the contribution of ionic resonance structure (27) to the carbonyl group of

(28) a shift to higher wave length or lower frequency was obtained.

33

C O C O

32 33

Based on the above discussion the band for the unconjugated carbonyl group

appearing at 1718 cm-1 and that for benzylidene acetophenone appearing at 1659 cm-1

can be well understood for the latter was due to conjugation with a phenyl group and an

aliphatic double bond.

Winecoff and Boykin99 studied the influence of conformation on transmission of

electronic effects in α, β-unsaturated ketones. They measured the carbonyl stretching

frequencies of s-cis and s-trans conformers of a series of substituted methyl styryl

ketones in CCl4 solution. The lowest carbonyl frequencies were observed with the

strongest electron withdrawing group. The frequencies for both conformers were

correlated with σ+ constants. A comparison of ρ value for the two conformers exhibits

similar ability to transmit electronic effects in both cases. The carbonyl stretching

frequencies of both conformers correlate with Swain-Lupton117 parameters (F & R) by

multiple correlation method giving good correlation coefficients (s-cis, 0.96 and s-trans,

0.953).

The s-cis carbonyl stretching frequencies of three series of substituted Α,β-

unsaturated ketones (34) have been determined in chloroform by Silver and Boykin100.

34

H

H

O

A B

34

One series contains substituents in ring A, one in ring B, and another

substituents in both ring.

The carbonyl stretching frequencies with substituents in ring A were correlated

with three different σ constants, viz., σ, σ+ and σ0. But the correlation was much

successful with higher degree of correlation through the equation (5) given below.

Ν = 6.24σ+ + 1666.7 …(5)

This implied that there was significant resonance interaction between the

substituents and the carbonyl group even though they were separated by intervening

groups. The ρ value of 6.24 obtained for the α,β-unsaturated ketones should be

compared with the value of 12.3 obtained from a similar study on acetophenones121.

The ratio of values gave a transmission co-efficient of 0.51 for the ethylene group. The

carbonyl frequencies correlated with Swain-Lupton parameters117 failed to produce

good correlation, but they gave better correlation with σ+. The value obtained for the

resonance contribution was 44%, for the styryl substituted series (34). This was similar

to those obtained for the acetophenones and benzophenones. This may possibly

suggest that the double bond transmitted the resonance effect very efficiently.

The existence of s-cis and s-trans conformations in relation to carbonyl group

was also reported in a series of trans-1-phenyl-3-(5-aryl-2-furyl)-propenones (35) and

trans-1-phenyl-3-(5-aryl-2-thienyl) propenones (36)118.

35

OCH

CH

O

35

SCH

CH

O

36

A comparison of the νs-cis (C=O) frequencies of compounds in series (35) with

those of series (36) showed that exchange of the furan ring for the thiophene ring

causes a frequency decrease of 1.5-3.5 cm-1 in CCl4 and CHCl3. The insertion of the

furan or thiophene intervening group in the Α,β-unsaturated ketone (37) produces

significant decrease in both the s-cis and the s-trans frequency.

CH

CH

O

37

In passing from CCl4 to CHCl3, the (C=O) frequencies of compounds (27), (28)

and (29) were decreased by 6.0 - 6.5 cm-1 and in the case of the νs-trans (C=O)

frequencies the similar decrease of 10 cm-1 was observed. This was attributed to the

carbonyl bonds of s-trans conformers having more solvent sensibility, than those of the

corresponding s-cis conformers122.

Statistically significant linear free energy relationship was obtained between

νC=O with σ+ constants, but only poorer correlations were obtained using σ values in all

cases. The data were analyzed employing Swain-Lupton117, F and R constants leading

36

to only poor correlations. The parameters of the linear free energy relationship for series

(35) and (36) were compared with those for (37). With the aid of the slopes of νC=O

versus σ+ constants in series (35-37), the transmission factors for the furan and

thiophene rings were calculated and related to data published earlier, the determined

order of transmission for the intervening groups was furan > thiophene.

1.1.3 NMR Spectral Study

Though 1H and 13C NMR spectral studies have been used in numerous structural

problems123, their use in structure – parameter correlation has become popular only in

recent time. Hamer, Peat and Reynolds124 determined the 1H and 13C chemical shifts

of 4-substituted styrenes, α-methylstyrene and α-t-butylstyrene under conditions

corresponding to infinite dilution in a non-polar medium. Correlation of the internal

chemical shift difference for the vinyl protons, Δδ(B-C) in (38) with electrical field

components estimated by CNDO/2 molecular orbital calculations provided conclusive

evidence for the existence of a through-space field effect. The CNDO/2 calculations

for 4-substituted-1-vinylbicyclo [2.2.2] octanes and ethylenemethyl X pairs indicated that

this through-space effect has a geometric dependence similar to that predicted by the

Buckingham equation.

CC

HB

38

HA

HC

Correlation of vinyl 1H and 13C chemical shifts and charge densities with field (F)

and resonance (R) parameters provided a self-consistent picture of electrical effects in

37

these compounds. The 1H chemical shifts for some derivatives were affected by

magnetic effects but did not obscure the overall pattern of electronic effects. This

pattern of electronic effects could be completely accounted for by a model which

assumes that substituent effects can be transmitted through space (field effects), viz.

conjugation interaction (resonance effect) or by polarization of the styrene π- electron

system by the polar C-X bond (π-polarization effects).

The 1H NMR spectral correlations with F and R parameters were used to

estimate the self-consistent and apparently, reasonable ΔX values for C=N and C=C-H

group and F and R parameters for carbonyl substituents. The halogens also gave the

anomalous results. A comparison of various correlations suggested that these

anomalies were magnetic in origin.

The 1H NMR spectra of trans-3-phenylmethylidenephthalide (39) and

trans-3-phenylthiomethylidenephthalide (40) derivatives were investigated by Vide et.al.,

and Perjessy et.al., 125.

C

O

C

H

O

X

39

C

O

C

H

O

40

S

X

In both the series there was good linear correlation of corrected chemical shifts of

meta protons, ortho protons and methane protons with σ constants. The correlation of

chemical shifts for the anisotropy of substituents and for changes of ring current in the

substituted aromatic ring has been done by the method of Yamada et.al.,126. The

38

influence of bridge hetero atom on the transmission of electronic effects of substituents

through the molecule should be less effective. Such type of influence of the hetero atom

was the obvious limitation of the exchange of energy of the valance electrons between

the substituted phenyl group and the methane proton. In view of this, the value of the

appropriate coupling constants was decreased and the transfer of the secondary steric

effects of the substituents was also considerably lowered.

Dommock, Carter and Ralph127 recorded the 1H NMR spectra of several

substituted 1-phenyl-1-en-3-ones. The olefinic protons (Hα and Hβ) were correlated with

σ and σ+ constants.

Savin and coworkers128 recorded the 1H NMR spectra of α, β-unsaturated

ketones of the type R-C6H4-CH=CH-CO-CH3 and found good correlation of Hα with σ+

constants and Hβ with σ0 constants. The substituents effects were thus understood to

have transmitted predominantly by the resonance mechanism to Hα and by the inductive

mechanism to Hβ.

The 13C NMR spectra of para- and meta- substituted α,β-unsaturated ketones,

3-aryl-1-phenyl-2-propane (41) and 1-aryl-3-phenyl-2-prop-1-en-3-one (42) were

obtained by Solcaniova, Toma and Gronowitz129. The correlation of 13C chemical shifts

with Hammett σ constants showed that in (42) the Cα was more sensitive to the effect of

polar substituents giving an excellent correlation coefficient r = 0.992. A relatively good

correlation was obtained for the Cβ with r = 0.947 and slope of opposite sign.

39

CH

CH

O

X

41

CH

CH

O

42

X

Quite good correlation were also found for ring carbons C-1, C-1' and C-4'. In

(42) the situation was quite opposite than in (41) that the Cβ was more sensitive to the

effect of substituent with a positive slope, while the Cα correlation has a negative slope.

The 13C chemical shifts were correlated well with Swain-Lupton117 parameters. The

chemical shifts of Cα were affected mainly by the resonance effects while inductive

effect contributed significantly to the shielding of Cβ in (40). The situation was opposite

in (42).

Solcaniova and Toma129-130 have studied the effect of substituents on the

1H NMR spectra of α,β-unsaturated ketones of the above two series (40) and (42). They

determined the chemical shifts of ethylenic protons and aromatic protons. The chemical

shifts of Hα are at higher field than that of the Hβ in both the series. The α-protons were

well separated from the signals of the aromatic protons. In the case of para- and meta-

NO2 derivatives of the series (41), however, the signals of the aromatic protons and

those of Hα and Hβ were assigned with the aid of the lanthanide shift reagents,

Eu(Fod)3. The α-proton signal in both series was assigned by INDOR double resonance

technique.

The Hα chemical shifts in series (41) were the most sensitive to the effects of the

substituents. The ethylenic protons were correlated with Hammett σ constants. The

opposite signs of the slope for Hα and Hβ in series (41) and (42) have been attributed to

40

the polarization of the C=C double bond being predominantly caused by the carbonyl

group. In series (41) the electron attracting substituents lower the electron density at the

α-carbon and so they act against the normal polarization with positive slope while in

series (42) they act in agreement with the normal polarization with negative slope. From

the results of the Swain and Lupton117 correlation the resonance effects of the

substituents were dominant for Hα in series (41) while in series (42) both inductive and

resonance effects have similar contribution. The chemical shifts of the β-protons in

series (41) did not correlate with any of the substituent parameters, while in series (42),

there was some correlation with Hammett σ constants.

1.1.4 Structure – Parameter Correlation

The correlation of structure of compounds of the type (43) containing a

substituent (R) and a side chain (Y), with their reactivity was usually a linear relationship

involving logarithms of rate constant (k) or equilibrium constants (K) which has provided

the main basis for quantitative structure-reactivity relationship, viz., the well-known

Hammett equation131-135 which takes the forms (6) and (7).

log (k/k0) = σ ρ …(6)

log (K/K0) = σ ρ …(7)

where k and K are the rate constant and equilibrium constant respectively of the meta-

or para- substituted benzene derivatives.

Y

R

43

41

The k0 and K0 are the corresponding quantities of the unsubstituted compound

(parent compound) of the two empirical constants in the Hammett equation, σ is

substituent constant and ρ is the reaction constant. The substituent constant measures

quantitatively the electron donating or electron accepting power (relative to hydrogen) of

the substituent and is, in principle, independent of the nature of the reaction. The

reaction constant depends on the nature of the reaction (including conditions such as

reagents, solvent, catalyst and temperature) and measures the susceptibility of the

reaction to inductive and resonance effects. The equations (6) and (7) hold good for

meta- or para- substituted benzene derivatives.

From the work of Hammett and that of Taft, have come a variety of substituent

and reaction parameters of great value in summarizing and understanding the influence

of molecular structure on the chemical reactivity. The substituent constants have also

found application in fields very different from those of rates and equilibrium of organic

reactions. They have been applied extensively in optical spectroscopy (infrared, visible

and ultraviolet), nuclear magnetic resonance spectroscopy (1H, 13C, 19F and other

nuclei) and mass spectrometry of organic compounds.

In UV spectra, the absorption maximum (λmax) depends on the π-electrons and

non-bonded electrons on the α,β-unsaturated carbonyl system. In developing

correlation equations for UV absorption maximum it was logical to replace log k or log K

term of linear free energy relationships by the bond absorption for the substituted

member of the series. Thus Hammett equation assumes the form as given in (8).

λ = ρ σ + λ0 …(8)

In IR spectra, the absorption frequency was directly proportional to the strength

of the relevant vibration. In developing correlation equations for infrared frequencies it

42

was logical to replace log k or log K term of linear free energy relationships by ν the

bond frequency for the substituted member of the series. Thus Hammett equation

assumes the form as given in (9).

ν = ρ σ + ν 0 …(9)

In NMR spectra, the proton or the carbon chemical shift (δ) depends on the

electronic environment of the nuclei concerned. These shifts can be correlated with

reactivity parameters. Thus the Hammett equation may be used in the form as in (10).

δ = ρ σ + δ0 …(10)

where δ0 was the chemical shift in the corresponding parent compound

Prediction of the structure, stereochemical and physicochemical properties of

2-thienyl, 4-fluorophenyl and 2-naphthyl Α,β-unsaturated ketones have been studied by

Subramanian et.al.,136. The quantitative structure activity relationship and quantitative

property relationship of the organic substrates of the 6- and 4-substituted naphthyl

α,β-unsaturated ketones have been studied from the spectral data associated with their

molecular equilibration137-140. The vibrational frequencies of carbonyl groups gave two

isomeric molecular structures in unsaturated ketones such as s-cis and s-trans

conformers. The s-cis carbonyl group absorption frequencies are higher than those of

the s-trans carbonyl group. Based on this, the structure of molecular equilibration can

be predicted 59,107,141, in geometrical isomers, keto-enol tautomerism in unsaturated

carbonyl compounds, alkenes, alkynes, styrenes and nitrostyrenes. The correlations of

deformation modes of CHip, CHop, CH=CHop and C=Cop of various α,β-unsaturated

ketones have also been studied142. Nuclear magnetic resonance spectroscopy provides

information about the number of protons present in the molecules and their types (either

E or Z). Based on their coupling constant J in Hz, these types of protons can be

43

identified in the organic molecules. If the molecules possess a substituent in the

aromatic ring, the corresponding absorption frequencies in IR and the chemical shift in

NMR vary from ketone to ketone depending upon the type of the substituents (electron-

donating or electron-withdrawing). From these data, the effect of substituents have been

studied on the particular functional group of the molecules by means of regression

analysis136,143-144. The out-of-plane and in-plane deformation frequencies in the

fingerprint region are also used for QSAR and QPR study145. Vanangamudi et al., have

studied the spectral linearity of some 6-substituted ω-bromo-2-naphthyl ketones and

their esters by IR and NMR spectral data146.

However there is no information available regarding UV, IR, NMR spectral

characterization and assessment of substituent effects in literature for substituted styryl

3,4,5-trimethoxyphenyl ketones, styryl 3-bromophenyl ketones, styryl 3-cyanophenyl

ketones, styryl 2-pyrrolyl ketones and 3-methylphenyl ketones. Hence it is proposed to

synthesize some substituted styryl 3,4,5-trimethoxyphenyl ketones, styryl

3-bromophenyl ketones, styryl 3-cyanophenyl ketones, styryl 2-pyrrolyl ketones and

styryl 3-methylphenyl ketones by adopting various synthetic methods using different

efficient catalysts and to evaluate the assessment of substituent effect as well as their

biological activities.

44

1.2 MATERIALS AND METHODS

The following five ketones namely 3,4,5-trimethoxyacetopheneone,

3-bromoacetophenone, 3-acetylbenzonitrile, 2-acetylpyrrole, 3-methyl acetophenone,

2-acetylpyrrole and 3-methyl acetophenone have been procured from Sigma Aldrich

Chemical Company, Bengaluru-100.

1.2.1 Preparation of compounds

1.2.1.1 Series-A

1.2.1.1.1 Styryl 3,4,5-trimethoxyphenyl ketone

A solution of benzaldehyde (1mmol) and 3,4,5-trimethoxyacetophenone (1mmol),

sodium hydroxide (0.5g) and 10 ml of ethanol were shaken occasionally for 1 hour147 as

shown in Scheme-I. After the completion of the reaction, as monitored by TLC, the

mixture was cooled at room temperature. The resulting precipitate was filtered and

washed with cold water. The product appeared as pale yellow solid. Then this was

recrystallized using ethanol to obtain pale yellow glittering solid melting at 65-66 oC.

CH3O

H3CO

OCH3

OCH3

OO

OCH3

H3CO

H3CO

X

H

NaOH

EtOH,

Scheme-I

45

1.2.1.1.2 3-bromostyryl 3,4,5-trimethoxyphenyl ketone

This compound was prepared by following the above Aldol condensation method

using 3-bromobenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the product

was recrystallized using ethanol to obtain pale yellow glittering solid melting at 56-57oC.

1.2.1.1.3 4-bromostyryl 3,4,5-trimethoxyphenyl ketone


using 4-bromobenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the product

was recrystallised using ethanol to obtain pale yellow glittering solid melting at 82-83oC.

1.2.1.1.4 2-fluorostyryl 3,4,5-trimethoxyphenyl ketone


using 2-fluorobenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the product

was recrystallised using ethanol to obtain pale yellow glittering solid melting at

147-148oC.

1.2.1.1.5 2- methoxystyryl 3,4,5-trimethoxyphenyl ketone


using 2-methoxybenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the

product was recrystallised using ethanol to obtain pale yellow glittering solid melting at

88-89 oC.

1.2.1.1.6 4-methoxystyryl 3,4,5-trimethoxyphenyl ketone


using 4-methoxybenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the

46

product was recrystallised using ethanol to obtain pale yellow glittering solid melting at

130-131 oC.

1.2.1.1.7 2-methylstyryl 3,4,5-trimethoxyphenyl ketone


using 2-methylbenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the product

was recrystallised using ethanol to obtain pale yellow glittering solid melting at 42-43 oC.

1.2.1.1.8 4-methylsytyryl 3,4,5-trimethoxyphenyl ketone


using 4-methylbenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the product

was recrystallised using ethanol to obtain pale yellow glittering solid melting at

186-187 oC.

1.2.1.1.9 4-nitrostyryl 3,4,5-trimethoxyphenyl ketone


using 4-nitrobenzaldehyde and 3,4,5-trimethoxyacetophenone147. Finally the product

was recrystallised using ethanol to obtain pale yellow glittering solid melting at 52-53 oC.

1.2.1.2 Series-B

1.2.1.2.1 Styryl 3-bromophenyl ketone

A solution of benzaldehyde (1mmol) and 3-bromoacetophenone (1mmol), sodium

hydroxide (0.5g) and 10 ml of ethanol were shaken occasionally for 1 hour147 as shown

Scheme-II. After the completion of the reaction, as monitored by TLC, the mixture was

cooled at room temperature. The resulting precipitate was filtered and washed with cold

47

water. The product appeared as pale yellow solid. Then this was recrystallised using

ethanol to obtain pale yellow glittering solid melting at 322-323 oC.

CH3O

Br

OO

BrX

H

NaOH

EtOH,

Scheme-II

1.2.1.2.2 2-bromostyryl 3-bromophenyl ketone


using 2-bromobenzaldehyde and 3-bromoacetophenone147. Finally the product was

recrystallised using ethanol to obtain pale yellow glittering solid melting at 220-221 oC.

1.2.1.2.3 2-chlorostyryl 3-bromophenyl ketone


using 2-chlorobenzaldehyde and 3-bromoacetophenone147. Finally the product was


1.2.1.2.4 4-chlorostyryl 3-bromophenyl ketone


using 4-chlorobenzaldehyde and 3-bromoacetophenone147. Finally the product was


48

1.2.1.2.5 4-fluorostyryl 3-bromophenyl ketone


using 4-fluorobenzaldehyde and 3-bromoacetophenone147. Finally the product was


1.2.1.2.6 4-methoxystyryl 3-bromophenyl ketone


using 4-methoxybenzaldehyde and 3-bromoacetophenone147. Finally the product was


1.2.1.2.7 4-methylstyryl 3-bromophenyl ketone


using 4-methylbenzaldehyde and 3-bromoacetophenone147. Finally the product was


1.2.1.2.8 3-nitrostyryl 3-bromophenyl ketone


using 3-nitrobenzaldehyde and 3-bromoacetophenone147. Finally the product was


1.2.1.2.9 4-nitrostyryl 3-bromophenyl ketone


using 4-nitrobenzaldehyde and 3-bromoacetophenone147. Finally the product was


49

1.2.1.3 Series-C

1.2.1.3.1 Styryl 3-cyanophenyl ketone

A solution of benzaldehyde (1mmol) and 3-cyanoacetophenone (1mmol), sodium

hydroxide (0.5g) and 10 ml of ethanol were shaken occasionally for 1 hour147 as shown

in Scheme-III. After the completion of the reaction, as monitored by TLC, the mixture

was cooled at room temperature. The resulting precipitate was filtered and washed with

cold water. The product appeared as pale yellow solid. Then this was recrystallised

using ethanol to obtain pale yellow glittering solid melting at 209-210 oC.

CH3O

CN

OO

CNX

H

NaOH

EtOH,

Scheme-III

1.2.1.3.2 3-bromostyryl 3-cyanophenyl ketone


using 3-bromobenzaldehyde and 3-cyanoacetophenone147. Finally the product was

recrystallised using ethanol to obtain pale yellow glittering solid melting at 166-167oC.

1.2.1.3.3 4-bromostyryl 3-cyanophenyl ketone

This compound was prepared by following the above Aldol condensation

method using 4-bromobenzaldehyde and 3-cyanoacetophenone147. Finally the product

50

was recrystallised using ethanol to obtain pale yellow glittering solid melting at 160-

161oC.

1.2.1.3.4 2-chlorostyryl 3-cyanophenyl ketone


using 2-chlorobenzaldehyde and 3-cyanoacetophenone147. Finally the product was


1.2.1.3.5 3-chlorostyryl 3-cyanophenyl ketone


using 3-chlorobenzaldehyde and 3-cyanoacetophenone147. Finally the product was


1.2.1.3.6 2-methoxystyryl 3-cyanophenyl ketone


using 2-methoxybenzaldehyde and 3-cyanoacetophenone147. Finally the product was










51

1.2.1.3.9 4-methylstyryl 3-cyanophenyl ketone


using 4-methylbenzaldehyde and 3-cyanoacetophenone147. Finally the product was


1.2.1.3.10 3-nitrostyryl 3-cyanophenyl ketone


using 3-nitrobenzaldehyde and 3-cyanoacetophenone147. Finally the product was


1.2.1.4 Series-D

1.2.1.4.1 Styryl 2-pyrrolyl ketone

An appropriate equi-molar quantities of pyrrole-2-methyl ketone (2 mmol),

benzaldehyde (2 mmol) and Fly ash: H2SO4 (0.5 g) were taken in Borosil tube and

tightly capped. The mixture was subjected to microwave heated for 5-6 minutes in a

microwave oven148 as shown in Scheme-IV (LG Grill, Intellowave, Microwave Oven,

160-800W) and then cooled to room temperature. The organic layer was separated with

dichloromethane and the solid product was obtained on evaporation. The solid, on

recrystallization with benzene-hexane mixture gave glittering pale yellow solid melting at

135-136oC. The insoluble catalyst was recycled by washing the solid reagent remained

on the filter by ethyl acetate (8 mL) followed by drying in an oven at 100°C for 1hr and it

was made reusable for further reactions.

52

NH

O CH3 OO

X

H

NH

Fly-ash:H2SO4

MW, 460 W

Scheme-IV

1.2.1.4.2 2-chlorostyryl 2-pyrrolyl ketone

This compound was prepared by following the microwave irradiation technique

using 2-chlorobenzaldehyde and 2-acetylpyrrole148. Finally the product was

recrystallised using benzene-hexane mixture gave pale yellow glittering solid melting at

122-123 oC.


This compound was prepared by following the above microwave irradiation

technique using 3-chlorobenzaldehyde and 2-acetylpyrrole148. Finally the product was

recrystallised using benzene-hexane mixture gave pale yellow glittering solid sublimes

at 360 oC.



technique using 4-chlorobenzaldehyde and 2-acetylpyrrole148. Finally the product was


156-157 oC.

53

1.2.1.4.5 3-fluorostyryl 2-pyrrolyl ketone


technique using 3-fluorobenzaldehyde and 2-acetylpyrrole148. Finally the product was


at 360 oC.

1.2.1.4.6 4-fluorostyryl 2-pyrrolyl ketone


technique using 4-fluorobenzaldehyde and 2-acetylpyrrole148. Finally the product was


86-87 oC.

1.2.1.4.7 2-methoxystyryl 2-pyrrolyl ketone


technique using 2-methoxybenzaldehyde and 2-acetylpyrrole148. Finally the product was


at 360 oC.



technique using 3-methoxybenzaldehyde and 2-acetylpyrrole148. Finally the product

was recrystallised using benzene-hexane mixture gave pale yellow glittering solid

melting at 110-111 oC.

54



technique using 4-methoxybenzaldehyde and 2-acetylpyrrole148. Finally the product was


134-135 oC.

1.2.1.4.10 4-methylstyryl 2-pyrrolyl ketone


technique using 4-methylbenzaldehyde and 2-acetylpyrrole148. Finally the product was


148-149 oC.

1.2.1.4.11 3-nitrostyryl 2-pyrrolyl ketone


technique using 3-nitrobenzaldehyde and 2- acetylpyrrole148. Finally the product was


128-129oC.

1.2.1.4.12 4-nitrostyryl 2-pyrrolyl ketone


technique using 4-nitrobenzaldehyde and 2-acetylpyrrole148. Finally the product was


201-202 oC.

55

1.2.1.5 Series-E

1.2.1.5.1 Styryl 3-methylphenyl ketone


technique using 3-methylacetophenone and benzaldehyde148 as shown in Scheme-V.

Finally the product was recrystallised using benzene-hexane mixture gave pale yellow

glittering solid melting at 58-59 oC.

CH3O

CH3

OO

CH3X

H

Fly-ash:H2SO4

MW, 460 W

Scheme-V

1.2.1.5.2 3-bromostyryl 3-methylphenyl ketone


technique using 3-bromobenzaldehyde and 3-methylacetophenone148. Finally the

product was recrystallised using benzene-hexane mixture gave pale yellow glittering

solid melting at 58-59 oC.

1.2.1.5.3 4-bromostyryl 3-methylphenyl ketone


technique using 4-bromobenzaldehyde and 3-methylacetophenone148. Finally the

56



1.2.1.5.4 3-chlorostyryl 3-methylphenyl ketone


technique using 3-chlorobenzaldehyde and 3-methylacetophenone148. Finally the



1.2.1.5.5 4-chlorostyryl 3-methylphenyl ketone


technique using 4-chlorobenzaldehyde and 3-methylacetophenone148. Finally the



1.2.1.5.6 4-fluorostyryl 3-methylphenyl ketone


technique using 4-fluorobenzaldehyde and 3-methylacetophenone148. Finally the



1.2.1.5.7 4-methylstyryl 3-methylphenyl ketone


technique using 4-methylbenzaldehyde and 3-methylacetophenone148. Finally the



57

1.2.1.5.8 3-nitrostyryl 3-methylphenyl ketone


technique using 3-nitrobenzaldehyde and 3-methylacetophenone148. Finally the product


sublimes at 360 oC.

1.2.1.2.9 4-nitrostyryl 3-methylphenyl ketone


technique using 4-nitrobenzaldehyde and 3-methylacetophenone148. Finally the product


melting at 70-71 oC.

58

1.2.2 Spectrophotometers

1.2.2.1 Instrumentation for UV Spectra

The UV spectra were recorded on SHIMADZU-1650 SPECTROMETER in

spectral grade methanol at the Department of chemistry, Annamalai University,

Annamalainagar

1.2.2.2 Instrumentation for IR Spectra

IR spectra of all ketones were recorded on AVATAR – NICOLET 330

FT-IR spectrophotometer. The sample was mixed with KBr and pellet technique was

adopted to record the spectra.

1.2.2.3 Instrumentation for 1H and 13C NMR Spectra

The 1H and 13C NMR Spectra of all α,β-unsaturated ketones were recorded using

the following NMR spectrometers:

(i) BRUKER, 400MHz model Spectrometer at IISC, Bengaluru.

(ii) BRUKER AVIII 5000, 500MHz for 1H NMR spectra and 125.46 MHz for 13C NMR

spectra model Spectrometer at IIT, Chennai.

(iii) BRUKER, 400MHz model Spectrometer at Annamalai University, Annamalai

nagar.

59

1.3 RESULTS AND DISCUSSION

1.3.1 Correlation analysis of UV spectral data of α,β-unsaturated ketones

The effect of substituents on ultraviolet absorption maximum λmaxCO(nm) of

α,β-unsaturated ketones has been correlated successfully with Hammett constants and

F and R parameters for substituted 2-pyrrolyl-α,β-unsaturated ketones62, 5-chloro-2-

thienyl-α,β-unsaturated ketones63 and 4-nitrophenyl-α,β-unsaturated ketones64. While

seeking Hammett correlation involving absorption maximum, the form of Hammett

equation employed is shown in equation (8).

λ = ρ σ + λ0 …(8)

where λ0 was the absorption maximum (λmax) of the corresponding parent compound.

The series of ketones chosen in the present study possess the α, β- unsaturated

system and have 3,4,5-trimethoxyphenyl, 3-bromophenyl, 3-cyanophenyl, 2-pyrrolyl and

3-methylphenyl as the R groups in (44).

The UV spectra recorded for the parent compounds in the present investigation

are shown in Figures: (1) – (5).

In the present investigation the effect substituents effects on the UV absorption

maximum (λmax) of these α,β-unsaturated ketones (Series A to E) has been studied. The

measured carbonyl absorption maximum (nm) values (λmax) of the α,β-unsaturated

ketones in the present study are given in Table – 1.

60

R

O

X

R X

OCH3

H3CO

H3CO

Br

CN

A

B

H, 3-Br, 4-Br, 2-F, 2-OCH3, 4-OCH3, 2-CH3, 4-CH3, 4-NO2

H, 2-Br, 2-Cl, 4-Cl, 4-F, 4-OCH3, 4-CH3, 3-NO2, 4-NO2

H, 2-Br, 4-Br, 2-Cl, 3-Cl, 2-OCH3, 3-OCH3, 4-OCH3, 4-CH3, 3-NO2

NH

CH3

D

E

H, 2-Cl, 3-Cl, 4-Cl, 3-F, 4-F, 2-OCH3, 3-OCH3, 4-OCH3, 4-CH3, 3-NO2, 4-NO2

H, 3-Br, 4-Br, 3-Cl, 4-Cl, 4-F, 4-CH3, 3-NO2, 4-NO2

C

44

Series

61

Figure - 1: UV Spectrum of styryl 3,4,5-trimethoxyphenyl ketone (Series-A)

Figure - 2: UV Spectrum of styryl 3-bromophenyl ketone (Series-B)

O

Br

O

OCH3

H3CO

H3CO

62

Figure - 3: UV Spectrum of styryl 3-cyanophenyl ketone (Series-C)

Figure - 4: UV Spectrum of styryl 2-pyrrolyl ketone (Series-D)

O

NH

O

CN

63

Figure - 5: UV Spectrum of styryl 3-methylphenyl ketone (Series-E)

O

CH3

64

Table-1

The UV absorption mximum λmax CO (nm) values of substituted styryl

3,4,5-trimethoxyphenyl (Series-A), 3-bromophenyl (Series-B), 3-cyanophenyl

(Series-C), 2-pyrrolyl (Series-D) and 3-methylphenyl ketones (Series-E)

Table continued...

Series-A: Substituted 3,4,5-trimethoxyphenyl ketones

S. No Substituent CO (λmax) nm

1 H 316.01

2 3-Br 305.54

3 4-Br 283.42

4 2-F 285.50

5 2-OCH3 346.51

6 4-OCH3 344.03

7 2-CH3 325.52

8 4-CH3 325.54

9 4-NO2 280.52

Series-B: Substituted styryl 3-bromophenyl ketones


1 H 310.50

2 2-Br 297.01

3 2-Cl 289.02

4 4-Cl 291.35

5 4-F 312.02

6 4-CH3 299.53

7 4-OCH3 289.52

8 3-NO2 302.03

9 4-NO2 307.01

65

Series-C: Substituted styryl 3-cyanophenyl ketones


1 H 314.02

2 3-Br 316.21

3 4-Br 306.11

4 2-Cl 245.03

5 3-Cl 316.02

6 2-OCH3 337.31

7 3-OCH3 339.20

8 4-OCH3 260.02

9 4-CH3 326.11

10 3-NO2 299.00

Series-D: Substituted styryl 2-pyrrolyl ketones


1 H 338.04

2 2-Cl 341.21

3 3-Cl 339.10

4 4-Cl 342.03

5 3-F 341.22

6 4-F 337.21

7 2-OCH3 354.52

8 3-OCH3 340.54

9 4-OCH3 354.52

10 4-CH3 342.57

11 3-NO2 339.31

12 4-NO2 354.02

Table continued...

66

1.3.1.1 Correlation analysis of UV spectral data of α,β-unsaturated ketones

in Series-A

All the observed absorption maximum λmaxCO (nm) values of all the

Series (A to E) of α,β-unsaturated ketones have been correlated with different

substituent constants and F and R parameters according to John shorter135. The

observed Carbonyl λmax (nm) values of all the substituted styryl 3,4,5-trimethoxyphenyl

ketones in Series-A are presented in Table-1. The results of statistical analysis are

presented in Table-2.

Series-E: Substituted styryl 3-methylphenyl ketones


1 H 308.82

2 3-Br 299.45

3 4-Br 317.01

4 3-Cl 302.22

5 4-Cl 312.04

6 4-F 307.62

7 4-CH3 321.26

8 3-NO2 290.21

9 4-NO2 273.82

67

Ta

ble

– 2

The

re

su

lts o

f sta

tistical a

na

lysis

of

UV

ab

so

rptio

n m

axim

um

λm

ax (

CO

) va

lue

s (

nm

) of

su

bstitu

ted

sty

ryl 3

,4,5

-trim

eth

oxyp

he

nyl

ke

tone

s (

Se

rie

s-A

) w

ith

H

am

me

tt c

on

sta

nts

σ,

σ+, σ

I &

σR a

nd

F a

nd

R p

ara

me

ters

Ab

so

rptio

n

ma

xim

um

co

nsta

nts

r

I ρ

s

n

co

rre

late

d d

eriva

tive

s

λm

ax (

CO

) n

m

σ

0.7

71

31

8.9

7

-55

.62

17

.26

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.9

07

31

9.5

8

-40

.17

6.3

3

8

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.866

33

1.3

6

-65

.88

20

.26

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.8

47

30

1.7

4

-50

.88

23

.82

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.767

33

2.3

2

-61

.57

20

.06

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.740

30

1.9

1

-40

.06

24

.78

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

r=

co

rre

latio

n c

oeff

icie

nt;

ρ=

slo

pe

; I=

inte

rcep

t; s

=sta

nd

ard

de

via

tio

n;

n

=n

um

be

r of

su

bstitu

en

ts

68

From Table-2, all the substituents except 4-OCH3 have shown satisfactory

correlation (r = 0.907) with Hammett substituent constant σ+. If the substituent

4-OCH3 is included in the regression this reduces the correlation considerably.

However the remaining Hammett substituent constants namely σ, σI & σR and F

and R parameters have shown poor correlations (r < 0.900) for λmax(nm) values. This is

due to the weak inductive, field and resonance effect of the substituents for predicting

the reactivity on the absorption through resonance as per the conjugative structure (45).

O

OCH3

H3CO

H3CO

O

CH3

45

H

H

All the substituents have shown negative ρ values with Hammett constants and F

and R parameters. This indicates that all the substituents reverse their effects for

absorption maximum (nm) in all α,β-unsaturated ketones belonging to Series-A. Some

of the single regression linear plots are shown in Figures: (6) & (7).

69

Figure - 6:

Plot of λmaxCO (nm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs σ+

Figure - 7:

Plot of λmaxCO (nm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs R

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

70

Since most of the single regression analyses, have shown poor correlations with

few Hammett constants and F and R parameters, it is decided to go for multi regression

analysis. The multi regression analysis of the absorption maximum of all

α,β-unsaturated ketones with inductive, resonance and Swain – Lupton’s117 parameters

produce satisfactory correlations as shown in equations (11) and (12).

λmaxCO (nm) = 320.541(±10.002) - 66.445(±22.935)σI - 51.722(±18.642)σR …(11)

(R = 0.982, n=9, P>95%)

λmaxCO (nm) = 320.864(±8.534) - 72.392(±18.523)F - 56.201(±19.947)R …(12)

(R = 0.987, n=9, P>95%)


in Series-B

The observed λmaxCO(nm) values of all the substituted styryl

3-bromophenyl ketones in series-B are presented in Table-1. These absorption

maximum values (nm) are correlated with different substituent constants and F and R

parameters according to John shorter135. The results of statistical analysis are


71

T

ab

le –

3

T

he

re

su

lts o

f sta

tistical a

na

lysis

of

UV

ab

so

rptio

n m

axim

um

λm

ax (

CO

) va

lue

s (

nm

) of

su

bstitu

ted

sty

ryl 3

-bro

moph

en

yl ke

tone

s

(Se

rie

s-B

) w

ith

Ha

mm

ett

con

sta

nts

σ,

σ+,

σI,

σR a

nd

F a

nd R

pa

ram

ete

rs

Ab

so

rptio

n

ma

xim

um

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

λm

ax (

CO

) n

m

σ

0.8

01

25

0.1

6

2.8

4

11

.52

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3,

4-O

CH

3,

3-N

O2,

4-N

O2

σ

+

0.7

81

25

0.4

3

2.2

0

11

.49

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3,

4-O

CH

3,

3-N

O2,

4-N

O2

σ

I 0

.847

24

7.1

8

9.2

8

11

.31

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3,

4-O

CH

3,

3-N

O2,

4-N

O2

σ

R

0.7

14

24

9.3

6

-6.4

1

11

.47

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3,

4-O

CH

3,

3-N

O2,

4-N

O2

F

0

.933

24

5.1

2

13

.77

2.9

0

8

H,

2-B

r, 2

-Cl, 4

-F, 4

-CH

3,

4-O

CH

3,

3-N

O2,

4-N

O2

R

0

.809

24

9.7

2

-3.3

0

11

.54

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3,

4-O

CH

3,

3-N

O2,

4-N

O2

r

= c

orr

ela

tio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

inte

rce

pt;

s =

sta

nd

ard

de

via

tio

n; n

= n

um

be

r of

su

bstitu

en

ts.

72

From Table-3, all the substituents except 4-Cl with F parameter has shown

satisfactory correlation (r = 0.933) for λmax CO (nm). If the substituent 4-Cl is included in

the regression this reduces the correlation considerably.

The Hammett substituent constants such as σ, σ+, σI & σR and R parameter have

shown poor correlations (r < 0.900) for λmax CO (nm) values. This is due to the weak

polar, inductive and resonance effects of these substituents for predicting their reactivity

on the absorption through resonance as per the conjugated structure (46).

O

Br

H

H

O CH3

46

All the substituents have shown positive ρ values with all Hammett constants

except σR and R parameter. This evidences the operation of normal substituent effect

for absorption maximum (nm) in all α,β-unsaturated ketones belonging to Series-B.

Some of the single regression linear plots are shown in Figures: (8) & (9).

73

Figure -8: Plot of λmaxCO (nm) of substituted styryl 3-bromophenyl ketones Vs F

Figure -9: Plot of λmaxCO (nm) of substituted styryl 3-bromophenyl ketones Vs σR

1. H 2. 2-Br 3. 2-Cl 4. 4-Cl 5. 4-F 6. 4-CH3 7. 4-OCH3 8. 3-NO2

9. 4-NO2


9. 4-NO2

74


few Hammett constants and R parameter, it is decided to go for multi regression

analysis. The multi regression analysis of the absorption maximum of all



λmax CO(nm) = 245.28(± 8.303) + 10.45 (±3.764) σI – 8.074(± 1.534) σR …(13)

(R = 0.928, n=9, P>90%)

λmax CO(nm) = 244.28 (±7.993) + 13.84(±5.483)F – 3.50(±1.273) R …(14)

(R = 0.953, n=9, P>90%)


in Series-C

The observed λmaxCO(nm) values of all the substituted styryl

3-cyanophenyl ketones in series-C are presented in Table-1. These absorption

maximum values (nm) are correlated with different substituent constants and F and R

parameters according to John shorter135. The results of statistical analysis are


75

T

ab

le –

4

The

re

su

lts o

f sta

tistical a

na

lysis

of

UV

ab

so

rptio

n m

axim

um

λm

ax (

CO

) va

lue

s (

nm

) of

su

bstitu

ted

sty

ryl 3

-cya

no

ph

en

yl ke

tone

s

(Se

rie

s-C

) w

ith

Ha

mm

ett

con

sta

nts

σ,

σ+,

σI &

σR a

nd

F a

nd R

pa

ram

ete

rs

Ab

so

rptio

n

ma

xim

um

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

λm

ax (

CO

) n

m

σ

0.9

00

30

4.7

7

-7.0

8

2.5

2

8

H,

3-B

r, 4

-Br,

3-C

l, 2

-OC

H3,

3-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.9

00

30

2.7

3

1.7

7

2.6

5

8

H,

3-B

r, 4

-Br,

3-C

l, 2

-OC

H3,

3-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.826

31

7.5

8

-37

.28

28

.32

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.7

85

30

1.4

3

-11

.04

29

.54

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.865

31

5.9

4

-33

.37

28

.73

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.752

30

0.8

9

-11

.54

29

.51

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

r

= c

orr

ela

tio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

inte

rce

pt;

s =

sta

nd

ard

de

via

tio

n;

n =

num

be

r of

su

bstitu

en

ts.

76

From Table-4, the Hammett constants namely σ and σ+ with absorption

maximum λmax CO(nm) values have shown satisfactory correlations (r = 0.900) for all

substituents except 2-Cl and 4-OCH3 substituents. If these two substituents namely

2-Cl and 4-OCH3 are included in the regression they reduce the correlations

considerably.

However the remaining Hammett substituent constants namely σI & σR and F and

R parameters have shown poor correlations (r < 0.900) with λmax CO (nm) values. This

is due to the weak inductive and resonance effects of these substituents for predicting

the reactivity on the absorption through resonance as per the conjugated structure (47).

O

CN

H

H

O CH3

47


and R parameters except σ+ constant. This indicates the operation of reverse

substituent effects for absorption maximum (nm) in all α,β-unsaturated ketones

belonging to Series-C. Some of the single regression linear plots are shown in

Figures: (10) & (11).

77

Figure - 10: Plot of λmaxCO (nm) of substituted styryl 3-cyanophenyl ketones Vs σ

Figure - 11: Plot of λmaxCO (nm) of substituted styryl 3-cyanophenyl ketones Vs σ+

1. H 2. 2-Br 3. 4-Br 4. 2-Cl 5. 3-Cl 6. 2-OCH3 7. 3-OCH3

8. 4-OCH3 9. 4-CH3

10. 3-NO2


8. 4-OCH3 9. 4-CH3

10. 3-NO2

78

. Since most of the single regression analyses, have shown poor correlations with

few Hammett constants and R parameter, it is decided to go for multi regression

analysis. The multi regression analysis of the absorption maximum of all α,β-

unsaturated ketones with inductive, resonance and Swain–Lupton’s117 parameters


λmaxCO (nm) = 319.142(±21.192) – 39.351(±13.527)σI + 4.893(±1.590)σR …(15)

(R = 0.929, n=10, P>90%)

λmaxCO (nm) = 316.276(±23.343) – 33.812(±12.582)F + 0.852(± 0.455) R …(16)

(R = 0.924, n=10, P>90%)


in Series-D

The observed λmax CO (nm) values of all the substituted styryl 2-pyrrolyl ketones

in series-D are presented in Table-1. These absorption maximum values (nm) are

correlated with different substituent constants and F and R parameters according to

John shorter135. The results of statistical analysis are presented in Table-5.

79

Ta

ble

- 5

The

re

su

lts o

f sta

tistical a

na

lysis

of

UV

ab

so

rptio

n m

axim

um

λm

ax (

CO

) va

lue

s (

nm

) of

su

bstitu

ted

sty

ryl 2

-pyrr

oly

l ke

tone

s (

Se

rie

s-D

)

with

Ha

mm

ett

con

sta

nts

σ,

σ+,

σI &

σR a

nd F

an

d R

pa

ram

ete

rs

Ab

so

rptio

n

ma

xim

um

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

λm

ax (

CO

) n

m

σ

0.6

24

34

4.3

5

-4.4

34

6.7

7

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

+

0.6

43

34

4.3

3

-5.2

09

6.4

6

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

I 0

.802

34

3.3

5

-0.6

89

6.9

8

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

R

0.8

17

34

2.7

2

-3.8

26

6.9

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.806

34

4.3

3

-1.7

32

6.9

6

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

R

0

.811

34

2.8

6

-2.6

42

6.9

4

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

r

= c

orr

ela

tio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

inte

rce

pt;

s =

sta

nd

ard

de

via

tio

n;

n =

num

be

r of

su

bstitu

en

ts.

80

From the Table-5, The Hammett constants namely σ, σ+, σI & σR and F and R

parameters have shown poor correlations (r < 0.900) with absorption maximum

λmax CO (nm) values for all the substituents.

This is due to weak polar, inductive, field and resonance effects of substituents

for predicting the reactivity on the absorption maximum through resonance as per the

conjugative structure (48).

N

O

O CH3

H

48

All the substituents have shown negative ρ values with Hammett

constants and F and R parameters. This indicates the operation of reverse substituent

effects for absorption maximum (nm) in all α,β-unsaturated ketones belonging to

Series-D.

.

81

Since all the single regression analyses, have shown poor correlations with

Hammett constants and F and R parameters, it is decided to go for multi regression


unsaturated ketones with inductive, resonance and Swain – Lupton’s117 parameters


λmaxCO (nm) = 342.241(±4.858) +1.175(±0.962)σI –3.949(±0.822) σR ...(17)

(R =0.914, n = 12, P > 90%)

λmaxCO (nm) = 343.655(±4.509) –2.035(±0.855)F -2.823(±0.771)R ...(18)

(R = 0.913, n = 12, P > 90%)


in Series-E

The observed λmaxCO (nm) values of all the substituted styryl 3-methylphenyl

ketones in series-E are presented in Table-1. These absorption maximum values (nm)

are correlated with different substituent constants and F and R parameters according

to John shorter135. The results of statistical analysis are presented in Table-6.

82

T

ab

le –

6

The

re

su

lts o

f sta

tistical a

na

lysis

of

UV

ab

so

rptio

n m

axim

um

λm

ax (

CO

) va

lue

s (

nm

) of

su

bstitu

ted

sty

ryl 3

-me

thylp

he

nyl ke

tone

s

(Se

rie

s-E

) w

ith

Ha

mm

ett

con

sta

nts

σ,

σ+,

σI &

σR a

nd

F a

nd R

pa

ram

ete

rs

Ab

so

rptio

n

ma

xim

um

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

λm

ax (

CO

) n

m

σ

0.9

87

31

5.3

4

-41

.36

2.4

5

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.9

75

31

2.1

8

-32

.25

2.4

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.964

31

8.5

8

-36

.90

2.8

8

8

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

4-N

O2

σ

R

0.8

58

29

8.9

5

-43

.75

12

.65

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.858

31

7.0

8

-32

.06

12

.64

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.756

29

8.0

9

-36

.81

12

.83

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

r

= c

orr

ela

tio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

inte

rce

pt;

s =

sta

nd

ard

de

via

tio

n;

n =

num

be

r of

su

bstitu

en

ts.

83

From Table-6, the Hammett substituent constants namely σ (r = 0.987),

σ+ (r = 0.975) and σI (r = 0.964) have shown satisfactory correlations. All the

substituents have shown satisfactory correlations with Hammett σ and σ+ constants.

But, the Hammett constant σI has also shown satisfactory correlation for all substituents

except 3-NO2 substituent. If the substituent 3-NO2 is included in the regression this

reduces the correlations considerably.

However the remaining Hammett substituent constant σR and F and R

parameters have shown poor correlations (r < 0.900) for λmax (nm) values. This is due to

the incapability of resonance and field effect of the substituents for predicting the

reactivity on absorption through resonance as per the conjugative structure (49).

O

CH3

H

H

CH2

H

49


and R parameters. This indicates the operation of reverse substituent effects for

absorption maximum (nm) in all α,β-unsaturated ketones belonging to Series-E. Some

of the single regression linear plots are shown in Figures: (12)-(15).

84

Figure-12: Plot of λmaxCO (nm) of substituted styryl 3-methylphenyl ketones Vs σ

Figure-13: Plot of λmaxCO (nm) of substituted styryl 3-methylphenyl ketones Vs σ+

1. H 2. 3-Br 3. 4-Br 4. 3-Cl 5. 4-Cl 6. 4-F 7. 4-CH3 8. 3-NO2 9. 4-NO2


85

Figure-14: Plot of λmaxCO (nm) of substituted styryl 3-methylphenyl ketones Vs σI

Figure-15:

Plot of λmaxCO (nm) of substituted styryl 3-methylphenyl ketones Vs R



86




unsaturated ketones with inductive, resonance and Swain – Lupton’s117 parameters


λmaxCO (nm) = 313.516(±6.213) – 35.350(±11.502)σI – 41.379(±12.464)σR …(19)

(R = 0.984, n=9, P>95%)

λmaxCO (nm) = 312.922(±5.423) – 37.56 (±10.946)F – 43.473(±12.948)R …(20)

(R = 0.987, n=9, P>95%)

87

1.3.2 CORRELATION ANALYSIS OF IR SPECTRAL DATA OF

α, β-UNSATURATED KETONES:

The substituent effects on the infrared stretching and bending mode frequencies

have been reported 99-103,149-151. The CO stretching, carbon-carbon group stretching and

bending frequencies can be assumed to be "mass insensitive". The CO, carbon-carbon

and carbon-hydrogen group frequencies have been successfully correlated with

Hammett σ constants in acetophenones102,152, benzophenones107, benzoyl chlorides105,

biphenyls, 9H-Fluorenyls153, substituted naphthyls141, thiophenes154, 2-pyrrolyl-

α,β-unsaturated ketones62, 5-chloro-2-thienyl-α,β-unsaturated ketones63 and

4-nitrophenyl-α,β-unsaturated ketones64. While seeking Hammett correlation involving

group frequencies, the form of the Hammett equation employed is shown in equation

(9).

ν = ρ σ + ν0 …(9)

where νо is the frequency for the parent member of the series.

In the present study, the synthesized α,β-unsaturated ketones are expected to

exist as s-cis and s-trans conformations with the incorporation of the R groups like

3,4,5-trimethoxyphenyl, 3-bromophenyl, 3-cyanophenyl, 2-pyrrolyl and 3-methylphenyl

in (44). The conformations expected are represented in (50). Literature survey

shows the existence of similar conformers in phenyl styryl ketones99, 155, styryl naphthyl

ketones156, styryl flurenyl ketones153 and in 3,4-dichlorophenyl ketones57.

88

R

O

X

R X

OCH3

H3CO

H3CO

Br

CN

A

B




NH

CH3

D

E


H, 3-Br, 4-Br, 3-Cl, 4-Cl, 4-F, 4-CH3, 3-NO2,

4-NO2

C

44

Series

89

Hayes and Timmons118 had assigned stretching frequencies for s-cis and s-trans

conformations as 1665 cm-1 and 1639 cm-1 respectively. Perjessy157 has made a

thorough investigation of substituent effect on the infrared stretching frequencies of

α,β-unsaturated ketones and has concluded that s-trans conformers transmit more

effectively than the s-cis conformers.

s-cis s-trans

50

CC R

OH

HX

CC O

RH

HX

The infrared spectra recorded in the present investigation without substituents in

phenyl rings are shown in Figures: (16) – (20).

90

F

igu

re-1

6:

IR

Sp

ectr

um

of

sty

ryl 3

,4,5

-trim

eth

oxyp

he

nyl k

eto

ne

(S

erie

s-A

)

O

OC

H3

H3C

O

H3C

O

91

F

igu

re-1

7:

IR S

pe

ctr

um

of

sty

ryl 3

-bro

mop

hen

yl ke

ton

e (

Se

rie

s-B

)

O

Br

92

F

igu

re-1

8:

IR S

pe

ctr

um

of

sty

ryl 3

-cya

no

ph

en

yl ke

ton

e (

Se

rie

s-C

)

O

CN

93

F

igu

re-1

9:

IR

Sp

ectr

um

of

sty

ryl 2

-pyrr

oly

l ke

ton

e (

Se

ries-D

)

O

N H

94

Fig

ure

-20

: IR

Sp

ectr

um

of

sty

ryl 3

-me

thylp

hen

yl ke

ton

e (

Se

rie

s-E

)

O

CH

3

95

From these figures, it is evident that all the compounds investigated in the

present study exist as an equilibrium mixture of two expected conformers. The larger

values of the stretching frequency for the s-cis conformation is due to the low mobility of

the p-electrons between the C C

CH

3

H CH

3

H

and C O

CH

3

H

framework.

Winecoff and Boykin99 have examined a similar system in which the R group was

replaced by H, CH3, n-Bu and C6H5. Perjessy157 has made a thorough investigation of

substituent effects on the infrared stretching frequencies of α,β-unsaturated ketones

and has concluded that s-trans conformers transmit more effectively than the s-cis

conformers. This has also been studied by Winecoff and Boykin 99. A similar trend in

transmission is observed in the present investigation too. In their investigation, Winecoff

and Boykin substituted R with n-butyl and phenyl groups which have rather larger steric

requirements. The difference in the transmission between the s-cis and s-trans isomer

was attributed to the difference in co-planarity in the two isomers. In the case of the

s-cis isomers, the R group and the a-hydrogen are in close proximity and their

interaction would affect the co-planarity of the carbonyl group and the styryl group.

Under such circumstances it would be expected that two isomers exist and the s-cis

isomer absorbs at a greater frequency. In the present investigation the R groups are


and hence there would be a larger steric requirement in the s-cis form which would result in

larger nC=O for it. Indeed, such an increase in nC=O values is observed in the study.

The observed νCOs-cis, νCOs-trans, νCHip, νCHop, νCH=CHop and νC=Cop

frequencies (cm-1) of all the series of the α,β-unsaturated ketones (A to E) of the present

study are given in Table-7.

96

Table-7

Infrared stretching frequencies ν(cm-1) of COs-cis, COs-trans , CHip, CHop, CH=CHop

and C=Cop modes of substituted styryl 3,4,5-trimethoxyphenyl (Series-A),

3-bromophenyl (Series-B), 3-cyanophenyl (Series-C), 2-pyrrolyl (Series-D) and

3-methylphenyl ketones (Series-E)

Table continued…

Series-A: IR frequencies of substituted styryl 3,4,5-trimethoxyphenyl ketones

Sl.No. Substituent ν(cm-1) CO s-cis

ν(cm-1) CO s-trans

ν(cm-1) CHip

ν(cm-1) CHop

ν(cm-1) CH=CHop

ν(cm-1) C=Cop

1 H 1659.95 1600.22 1164.57 757.69 986.15 563.12

2 3-Br 1664.24 1604.20 1166.02 782.34 980.67 572.02

3 4-Br 1664.08 1605.62 1163.61 793.54 979.88 487.45

4 2-F 1668.90 1597.75 1165.51 793.16 980.94 491.44

5 2-OCH3 1658.90 1593.80 1167.98 790.16 1026.26 521.04

6 4-OCH3 1664.51 1590.76 1161.82 796.08 981.93 505.76

7 2-CH3 1665.31 1602.67 1166.95 785.12 981.34 441.60

8 4-CH3 1659.72 1596.67 1165.57 789.94 984.39 498.63

9 4-NO2 1669.88 1603.04 1181.20 846.90 1020.16 600.06


1 H 1664.23 1605.56 1164.20 759.11 979.83 487.94

2 2-Br 1672.28 1562.34 1207.44 754.17 1020.34 449.41

3 2-Cl 1670.35 1600.92 1205.51 754.17 1039.63 549.71

4 4-Cl 1660.71 1583.56 1197.79 815.89 1031.92 551.64

5 4-F 1662.64 1595.13 1215.15 829.39 985.62 513.07

6 4-CH3 1662.64 1602.85 1207.44 800.46 985.62 491.85

7 4-OCH3 1678.07 1568.13 1209.37 783.10 1062.78 570.93

8 3-NO2 1660.71 1581.63 1187.36 779.24 1028.06 547.78

9 4-NO2 1681.93 1568.13 1205.51 785.03 1072.42 557.43

97



ν(cm-1) CO s-trans

ν(cm-1) CHip

ν(cm-1) CHop

ν(cm-1) CH=CHop

ν(cm-1) C=Cop

1 H 1659.11 1598.91 1163.46 786.49 1054.77 561.22

2 3-Br 1664.10 1610.02 1079.00 820.03 1018.02 466.12

3 4-Br 1670.11 1616.12 1172.12 818.06 1009.18 536.16

4 2-Cl 1683.02 1671.23 1111.13 848.11 1034.31 601.32

5 3-Cl 1610.00 1559.02 1069.03 848.04 1023.26 605.07

6 2-OCH3 1604.01 1550.10 1123.02 824.02 1028.22 549.30

7 3-OCH3 1665.20 1595.11 1105.10 824.31 1019.51 465.11

8 4-OCH3 1686.31 1595.02 1102.02 864.21 1031.23 602.03

9 4-CH3 1654.22 1603.13 1111.10 865.20 1022.16 603.38

10 3-NO2 1643.21 1614.02 1183.11 848.02 1035.07 600.45


1 H 1659.04 1596.71 1091.65 830.27 1017.75 547.95

2 2-Cl 1647.18 1627.81 1116.78 866.13 1068.57 563.22

3 3-Cl 1647.11 1593.18 1112.98 866.22 1056.90 580.52

4 4-Cl 1647.31 1624.11 1112.91 867.90 1086.22 561.24

5 3-F 1647.39 1627.84 1112.92 866.31 1018.33 563.21

6 4-F 1645.41 1587.38 1109.77 866.39 1058.81 599.80

7 2-OCH3 1679.92 1647.15 1020.32 866.21 1098.38 563.27

8 3-OCH3 1645.22 1585.42 1134.15 844.85 1051.13 596.09

9 4-OCH3 1645.37 1569.97 1170.77 823.52 1058.88 557.41

10 4-CH3 1643.28 1583.41 1132.19 866.58 1056.93 545.82

11 3-NO2 1652.85 1598.90 1114.81 858.30 1058.82 592.16

12 4-NO2 1643.27 1589.25 1109.07 844.81 1064.68 545.88

Table continued…

98



ν(cm-1) CO s-trans

ν(cm-1) CHip

ν(cm-1) CHop

ν(cm-1) CH=CHop

ν(cm-1) C=Cop

1 H 1665.31 1604.82 1166.61 7843.92 980.99 577.43

2 3-Br 1664.80 1605.10 1166.10 686.94 980.12 570.27

3 4-Br 1664.30 1605.60 1164.20 759.11 979.83 487.94

4 3-Cl 1665.30 1604.80 1166.60 722.84 980.99 577.43

5 4-Cl 1672.40 1598.20 1166.70 792.27 1013.00 550.07

6 4-F 1664.50 1592.10 1162.00 797.23 989.04 504.72

7 4-CH3 1692.20 1594.80 1186.70 848.77 1025.20 600.62

8 3-NO2 1659.10 1598.90 1163.50 983.96 1054.80 561.22

9 4-NO2 1673.30 1598.10 1181.50 855.15 1008.80 543.93

The study of substituent effects on the deformation modes of nCO modes of

s-trans and s-cis conformers, vinyl parts deformation modes such as CHop/ip, CH=CHop

and C=Cop have been done based on the work of Vanangamudi et. al.,62. The larger

deformation frequency for the present investigation is due to the low mobility

of electrons between the >C = C< and the -CH=CH- frame work. The lowest carbonyl

frequencies are expected in both the isomers with strongest electron donating groups

while highest frequencies are expected for strongest electron attracting groups.

99

1.3.2.1 Correlation analysis of IR spectral data of α,β-unsaturated ketones in

Series-A

The observed COs-cis, COs-trans, -CHout of plane, -CHin-plane, -CH = CH- out of plane and

>C = C< out of plane frequencies (νcm-1) of substituted styryl 3,4,5-trimethoxyphenyl ketones

in series-A are shown in Table-7. The corresponding s-trans and s-cis conformers of

substituted 3,4,5-trimethoxyphenyl α,β-unsaturated ketones are shown in (51).

O

OCH3

H

H

X

O

OCH3

H

H

X

s-cis s-trans

H3CO

H3CO

H3CO

H3CO

(51)

These frequencies are correlated with different substituent constants and F and

R parameters according to the approach of Jaffe133,152. The results of the statistical

analysis158 are presented in Table-8.

10

0

Ta

ble

- 8

The

re

su

lts o

f sta

tistical a

na

lysis

of

infr

are

d f

requ

en

cie

s ν

(cm

-1)

of

CO

s-c

is, C

Os-t

rans ,

CH

ip,

CH

op,

CH

=C

Hop a

nd

C=

Cop m

ode

s o

f

su

bstitu

ted s

tyry

l 3

,4,5

-trim

eth

oxyp

he

nyl ke

ton

es (

Se

rie

s-A

) w

ith

Ham

me

tt c

on

sta

nts

σ,

σ+,

σI &

σR a

nd

F a

nd

R p

ara

me

ters

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Os-c

is(c

m-1

) σ

0

.977

16

62

.95

8.6

2

1.6

1

7

H,

3-B

r, 4

-Br,

2-O

CH

3, 4

-OC

H3, 4

-CH

3, 4

-NO

2

σ

+

0.9

80

16

62

.69

07

.10

1.4

5

8

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 4

-CH

3, 4

-NO

2

σ

I 0

.966

16

61

.05

10

.12

1.1

1

7

H,

3-B

r, 4

-Br,

2-F

, 4

-OC

H3, 4

-CH

3, 4

-NO

2

σ

R

0.8

19

16

64

.61

3.1

4

4.0

8

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.974

16

60

.61

10

.39

0.8

0

7

H,

3-B

r, 4

-Br,

2-F

, 4

-OC

H3,

4-C

H3, 4

-NO

2

R

0

.809

16

64

.31

01

.36

4.1

5

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

νC

Os-t

rans(c

m-1

) σ

0

.648

15

98

.62

06

.89

4.7

1

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.7

23

15

98

.85

03

.21

5.1

6

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.749

15

97

.73

05

.89

5.1

3

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.7

66

16

02

.41

14

.12

3.9

9

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.817

15

98

.40

03

.15

5.2

9

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.867

16

02

.89

13

.08

3.9

9

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

T

ab

le c

on

tinu

ed..

.

10

1

F

requ

en

cy

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Hip

(cm

-1)

σ

0.7

56

11

66

.00

8.9

9

4.9

5

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.9

33

11

66

.3

3.9

2

1.7

1

8

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3

σ

I 0

.748

11

64

.00

10

.52

5.2

6

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.7

49

11

69

.50

11

.68

5.2

1

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.738

11

64

.50

7.8

9

5.2

3

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.855

11

70

.21

12

.02

5.0

1

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

νC

Hop(c

m-1

) σ

0

.764

78

7.8

5

42

.52

19

.13

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.7

35

78

7.7

9

28

.4

20

.99

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.764

77

5.9

2

59

.06

18

.98

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.8

24

79

7.9

3

24

.33

24

.16

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.876

77

6.4

8

50

.73

19

.89

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.821

79

7.9

8

19

.63

24

.35

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

Tab

le c

on

tinu

ed..

.

10

2

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

H=

CH

op(c

m-1

) σ

0

.703

99

1.1

1

1.6

5

19

.51

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.7

12

99

2.2

0

-5.1

3

19

.37

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.831

98

4.8

2

22

.70

18

.50

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.8

04

99

0.4

9

-3.7

9

19

.49

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.820

98

6.9

1

13

.67

19

.09

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.809

99

3.0

7

6.6

5

19

.43

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

νC

=C

op(c

m-1

) σ

0

.862

51

0.3

3

84

.69

42

.34

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.8

42

51

1.8

2

47

.43

47

.99

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.844

49

5.5

0

86

.22

47

.44

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.8

45

54

0.3

3

95

.21

47

.11

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.831

50

2.1

4

56

.02

50

.32

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.847

54

4.5

8

92

.10

46

.53

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

inte

rce

pt;

s =

sta

nd

ard

de

via

tio

n;

n =

num

be

r of su

bstitu

en

ts.

103

From Table-8, the νCOs-cis frequencies with Hammett constants namely

σ (r = 0.977), σ+ (r = 0.980) & σI (r = 0.966) and F (r = 0.974) parameter have shown

satisfactory correlations. All the substituents except 2-F and 2-CH3 have shown

satisfactory correlations with Hammett σ & σI constants and F parameter. In case of

Hammett σ+ constant, all the substituents except 2-CH3 have also shown satisfactory

correlations. These two substituents namely 2-F and 2-CH3 are reduce the correlations

considerably when they are included in regression.

The remaining Hammett constant σR and R parameter have shown poor

correlations (r < 0.900) for all the substituents. This is due weak resonsnce effect of the

substituents for predicting the reactivity on carbonyl groups through resonance as per

the conjugative structure (45).

O

OCH3

H3CO

H3CO

O

CH3

45

H

H

But in case of νCOs-trans stretching frequencies, all the Hammett constants

namely σ, σ+, σI & σR and F and R parameters have shown poor correlations (r < 0.900)

for all the substituents. This is due to weak polar, inductive, resonance and field effects

of substituents for predicting the reactivity on the carbonyl groups through resonance as

per the conjugative structure (45). Both the νCOs-cis and νCOs-trans stretching frequencies

have shown positive ρ values with Hammett substituent constants and F and R

parameters. This implies the operation of normal substituent effect for carbonyl

frequencies (cm-1) in all α,β-unsaturated ketones belonging to Series-A. Some of the

single regression linear plots are shown in Figures: (21) - (24).

104

Figure – 21:

Plot of νCOs-cis(cm-1) of substituted styryl 3,4,5-trimethoxylphenylphenyl ketones Vs σ

Figure – 22:

Plot of νCOs-cis(cm-1) of substituted styryl 3,4,5-trimethoxylphenylphenyl ketones Vs σ+

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

105

Figure -23:

Plot of νCOs-cis(cm-1) of substituted styryl 3,4,5-trimethoxylphenylphenyl ketones Vs σI

Figure -24:

Plot of νCOs-cis(cm-1) of substituted styryl 3,4,5-trimethoxylphenylphenyl ketones Vs F

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

106

From Table-8, the νCHip deformation modes with Hammett σ+ constant has

shown satisfactory correlation (r = 0.930) for all substituents except 4-NO2. If the

substituent 4-NO2 is included in regression this reduces the correlations considerably.

The remaining Hammett substituent constants namely σ, σ+ & σR and F and R

parameters have shown poor correlations (r < 0.900) for all substituents. This is due to

weak inductive, resonance and field effects of the substituents to transmit their

electronic effects from phenyl rings to vinyl CHip deformation modes through resonance

as per the conjugative structure shown in (45).

All the Hammett substituent constants and F and R parameters have shown poor

correlations (r < 0.900) with νCHop deformation modes for all substituents. This is due to

weak polar, inductive, resonance and field effects of the substituents to transmit their

electronic effects from phenyl rings to vinyl νCHop deformation modes through

resonance as per the conjugative structure shown in (45).

The correlations of both νCHip and νCHop deformation modes have shown

positive ρ values with Hammett constants and F and R parameters. It indicates the

operation of normal substituent effect for νCHip and νCHop deformation modes in all

α,β-unsaturated ketones belonging to Series-A. Some of the single regression linear

plots are shown in Figures: (25) & (26).

107

Figure – 25:

Plot of νCHip(cm-1) of substituted styryl 3,4,5-trimethoxylphenylphenyl ketones Vs σ+

Figure – 26:

Plot of νCHop(cm-1) of substituted styryl 3,4,5-trimethoxylphenylphenyl ketones Vs σ+

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

108

From Table-8, the deformation modes of νCH=CHop and νC=Cop frequencies of

substituted styryl 3,4,5-trimethoxyphenyl ketones with all Hammett substituent constants


for all the substituents.

This is due to weak polar, inductive, resonance and field effects of the

substituents to transmit their electronic effects from phenyl rings to vinyl νCH=CHop and

νC=Cop deformation modes through resonance as per the conjugative structure shown in

(45).

All the correlations for νCH=CHop deformation modes have shown positive

ρ values with Hammett constants and F and R parameters except σ+ and σR constants.

The correlations of νCH=CHip deformation modes with Hammett constants and F and R

parameters have also shown positive ρ values. This reveals the operation of normal

substituent effect for νCH=CHop and νC=Cop deformation modes in all α,β-unsaturated

ketones belonging to Series-A.

109


few Hammett constants and F and R parameters, it is decided to go for multi regression

analysis. The multi regression analysis of the stretching frequencies of all


produce satisfactory correlations as shown in equations (21)-(32).

νCOs-cis(cm-1) =1661.714(±1.953) + 10.165(±3.465)σI + 3.276 (±1.794) σR …(21)

(R = 0.969, n=9, P>95%)

νCOs-cis(cm-1) =1661.393(±1.692) + 11.136(±3.666) F + 3.852(±1.946) R …(22)

(R = 0.978, n=9, P>95%)

νCOs-trans(cm-1)=1600.702(±2.373) + 6.043(±2.425) σI + 14.195(±3.835) σR …(23)

(R = 0.973, n=9, P>95%)

ν COs-trans(cm-1)=1601.341(± 2.374) + 5.915(±2.078) F + 14.417(±4.465) R …(24)

(R = 0.974, n=9, P>95%)

νCHip (cm-1) =1166.499(±2.815) + 10.6541(±3.432)σI + 11.813(±3.913) σR…(25)

(R = 0.969, n=9, P>95%)

νCHip (cm-1) =1167.434(±2.556) + 10.662(±3.547) F + 14.395(±3.964)R …(26)

(R = 0.975, n=9, P>95%)

νCHop (cm-1) =781.152(±11.635) + 59.337(±16.653)σI + 25.089(±8.648)σR …(27)

(R = 0.969, n=9, P>95%)

νCHop (cm-1) =783.07 (±11.594) + 56.95 (±15.173) F + 32.33(±11.094) R …(28)

(R = 0.932, n=9, P>90%)

νCH=CHop (cm-1)=984.081(±12.024) + 22.664(±8.553)σI – 3.508(± 1.604)σR …(29)

(R = 0.969, n=9, P>95%)

νCH=CHop (cm-1)=988.986(± 12.258) + 15.622(±5.593)F + 10.134(±2.634)R …(30)

(R = 0.925, n=9, P>90%)

νC=Cop (cm-1) =515.642(±26.414) + 87.269(±25.528)σI + 96.302(±31.034)σR…(31)

(R = 0.964, n=9, P>95%)

νC=Cop (cm-1) =524.407(±26.463) + 77.054(±27.427)F + 109.290(±31.828)R…(32)

(R = 0.963, n=9, P>95%)

110


Series-B

The assigned νCO stretching frequencies of s-trans and s-cis conformers of all

substituted styryl 3-bromophenyl ketones in series-B are presented in Table-7 and the

respective conformers are shown in (52).

O

Br

H

H

X

O

Br

H

H

X

s-cis s-trans

(52)

The observed frequencies are correlated with different substituent constants and

F and R parameters according to the approach of Jaffe133,152. The results of the

statistical analysis158 are presented in Table- 9.

11

1

Ta

ble

- 9

The

re

su

lts o

f sta

tistical a

na

lysis

of

infr

are

d f

requ

en

cie

s ν

(cm

-1) o

f C

Os-c

is,

CO

s-t

rans ,

CH

ip,

CH

op,

CH

=C

Hop a

nd

C=

Cop m

od

es o

f

su

bstitu

ted s

tyry

l 3

-bro

mo

ph

en

yl ke

ton

es (

Serie

s-B

) w

ith

H

am

me

tt c

on

sta

nts

σ,

σ+,

σI &

σR

and

F a

nd

R p

ara

me

ters

Fre

qu

en

cy

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Os-c

is(c

m-1

) σ

0

.957

16

65

.50

18

.69

12

.74

8

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 3

-NO

2,

4-N

O2

σ

+

0.8

85

16

67

.40

11

.26

3.9

8

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.736

16

59

.61

23

.10

5.8

0

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.7

16

16

72

.27

23

.53

5.9

8

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.685

16

60

.98

17

.73

6.9

3

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.741

16

72

.69

19

.13

5.7

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

νC

Os-t

rans(c

m-1

) σ

0

.845

15

86

.65

-20

.34

13

.52

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.8

45

15

84

.49

-10

.26

14

.60

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.851

15

96

.15

-33

.67

13

.28

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.7

33

15

80

.24

-20

.46

15

.25

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.743

15

94

.74

-27

.33

14

.15

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.831

15

80

.26

-15

.05

13

.36

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

Tab

le c

on

tinu

ed..

.

11

2

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Hip

(cm

-1)

σ

0.8

50

12

03

.07

9.7

5

7.2

7

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.8

27

12

03

.97

7.7

0

6.6

2

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.832

12

00

.72

10

.04

7.9

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.8

22

12

06

.02

9.0

9

8.0

7

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.741

11

99

.66

11

.93

7.7

0

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.824

12

06

.56

8.9

0

7.8

8

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

νC

Hop(c

m-1

) σ

0

.724

78

7.6

0

-17

.99

26

.84

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.8

48

78

6.2

3

-20

.10

24

.44

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.800

78

5.1

9

0.1

4

27

.96

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.8

31

77

8.1

2

-38

.84

26

.04

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.822

77

6.5

6

22

.06

27

.23

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.855

77

4.5

3

-43

.21

23

.95

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

Tab

le c

on

tinu

ed..

.

11

3

Fre

qu

en

cy

Co

nsta

nt

s

r I

ρ

s

n

Co

rre

late

d d

eri

va

tive

s

νC

H=

CH

op(c

m-1

) σ

0

.956

10

17

.68

51

.21

5.5

6

6

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-CH

3, 4

-NO

2

σ

+

0.8

46

10

23

.26

23

.44

30

.02

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.900

99

3.3

7

85

.94

4.4

7

7

H,

2-B

r, 2

-Cl, 4

-F, 4

-CH

3, 3

-NO

2,

4-N

O2

σ

R

0.9

04

10

35

.19

58

.80

3.2

6

7

H,

2-B

r, 2

-Cl, 4

-F, 4

-CH

3, 3

-NO

2,

4-N

O2

F

0

.905

10

00

.26

61

.40

2.0

6

7

H,

2-B

r, 2

-Cl, 4

-F, 4

-CH

3, 3

-NO

2,

4-N

O2

R

0

.835

10

34

.46

40

.57

31

.14

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

νC

=C

op(c

m-1

) σ

0

.822

52

9.6

9

21

.89

41

.61

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.8

02

53

2.6

4

-1.5

6

42

.67

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.805

52

3.6

7

24

.61

42

.15

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.7

30

54

2.1

3

52

.17

40

.44

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.807

52

7.9

3

11

.78

42

.55

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.817

53

8.8

4

25

.34

41

.84

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lope

; I =

in

terc

ep

t;

s =

sta

nd

ard

devia

tio

n;

n

= n

um

be

r of

su

bstitu

ents

.

114

From Table-9, the νCOs-cis stretching frequencies with Hammett constant σ

has shown satisfactory correlation (r = 0.957) for all the substituents except 4-OCH3. If

the substituent 4-OCH3 is included in the regression this reduces the correlation

considerably. The remaining Hammett constants namely σ+, σI & σR and F and R

parameters have shown poor correlations (r < 0.900) for all substituents. This is due to

weak polar, inductive and resonance effects of the substituents transmit the electronic

effects from phenyl rings to carbonyl groups through resonance as per the conjugative

structure (46).

O

Br

H

H

O

(46)

CH3

All the correlations for νCOs-cis have shown positive ρ values with Hammett

constants and F and R parameters. This indicates the operation of normal substituent

effect for νCOs-cis frequencies in all α,β-unsaturated ketones belonging to Series-B.

The νCOs-trans stretching frequencies (cm-1) with all the Hammett substituent

constants namely σ, σ+, σI & σR and F and R parameters have shown poor correlations

(r < 0.900) for all the substituents. This is due to weak polar, inductive, resonance and

field effects of the substituents to transmit their electronic effects from phenyl rings to

carbonyl groups in all α,β-unsaturated ketones through resonance as per the

conjugative structure shown in (46). All the correlations for νCOs-trans(cm-1)

have shown

negative ρ values with Hammett substituent constants and F and R parameters. This

indicates the operation of reverse substituent effect for νCOs-cis frequencies in

115

all α,β-unsaturated ketones belonging to Series-B. Some of the single regression linear

plots are shown in Figures: (27) & (28).

Figure – 27:

Plot of νCOs-cis(cm-1) of substituted styryl 3-bromophenylphenyl ketones Vs σ

Figure – 28: Plot of νCOs-trans(cm-1) of substituted styryl 3-bromophenylphenyl ketones Vs σR


9. 4-NO2


9. 4-NO2

116

From Table-9, the regression analysis of νCHip and νCHop deformation modes

with Hammett σ, σ+, σI and σR constants and F and R parameters have shown poor

correlations (r < 0.900) for all the substituents. This is due to weak polar, inductive,

resonance and field effects of the substituents to transmit their electronic effects from

phenyl rings to vinyl νCHip and νCHop deformation modes through resonance as per the

conjugative structure shown in (46).

All the correlations have shown positive ρ value for νCHip deformation modes

with Hammett substituent constants and F and R parameters. This indicates the

operation of normal substituent effect for vinyl νCHip deformation modes in all

α,β-unsaturated ketones belonging to Series-B.

However the, correlations of νCHop deformation modes have shown negative

ρ values with Hammett constants and R parameters except σI and F parameter. This

indicates the operation of reverse substituent effect for νCHop deformation modes in all

α,β-unsaturated ketones belonging to Series-B.

From Table-9, the νCH=CHop deformation modes with Hammett substituent

constants namely σ (r = 0.956), σI (r = 0.900) & σR (r = 0.904) and F (r = 0.905)

parameter have shown satisfactory correlations. All the substituents except 4-F,

4-OCH3 and 3-NO2 have shown satisfactory correlations with Hammett constant σ. The

correlations with Hammett constant σI & σR and F parameter have also shown

satisfactory correlations for all substituents except 4-Cl and 4-OCH3 substituents.

These substituents namely 4-Cl, 4-F, 4-OCH3 and 3-NO2 reduce the correlations

considerably when they are included in regression analysis.

The remaining Hammett substituent constant σ+ and R parameter have shown

poor correlations (r < 0.900) for all substituents. This is due to the incapability of the

polar and resonance effects of the substituents to transmit their electronic effects from

117

phenyl rings to vinyl νCH=CHop deformation modes across four or five carbon atoms

through resonance as per the conjugative structure shown in (46).

All the correlations for νCH=CHop deformation modes have shown positive ρ

values with Hammett constants and F and R parameters. This indicates the operation of

normal substituent effects in all α,β-unsaturated ketones belonging to Series-B.

The regression analysis of νC=Cop deformation modes with all Hammett

substituent constants such as σ, σ+, σI & σR and F and R parameters have shown poor

correlations (r < 0.900) for all substituents. This is due to weak polar, inductive,

resonance and field effects of the substituents for predicting the reactivity on vinyl

νC=Cop deformation modes for all α,β-unsaturated ketones through resonance as per

the conjugative structure shown in (46).

. The correlations of νC=Cop deformation modes have shown positive ρ values

constant with all the Hammett constants and F and R parameters except σ+. This

indicates the operation of normal substituent effects for νC=Cop deformation modes in all

α,β-unsaturated ketones belonging to series-B. Some of the single regression linear

plots are shown in Figures: (29)-(32).

118

Figure – 29: Plot of νCH=CHop (cm-1) of substituted styryl 3-bromophenylphenyl ketones Vs σ

Figure – 30: Plot of νCH=CHop(cm-1) of substituted styryl 3-bromophenylphenyl ketones Vs σI


9. 4-NO2


9. 4-NO2

119

Figure – 31: Plot of νCH=CHop (cm-1) of substituted styryl 3-bromophenylphenyl ketones Vs σR

Figure – 32: Plot of νCH=CHop (cm-1) of substituted styryl 3-bromophenylphenyl ketones Vs F


9. 4-NO2


9. 4-NO2

120


few Hammett constants and F and R parameters. It is decided to go for multi regression

analysis. The multi regression analysis of stretching frequencies of all α,β-unsaturated

ketones with inductive, resonance and Swain-Lupton’s117 F and R parameters produce

satisfactory correlations as shown in equations (33)-(44).

νCOs-cis(cm-1) =1664.401(± 1.844) + 20.157(±3.714)σI + 20.33 3(±3.887)σR …(33)

(R = 0.958, n=9, P>90%)

νCOs-cis(cm-1) =1665.811(±2.142) + 17.357(±4.147) F +18.884(±3.554)R …(34)

(R = 0.941, n=9, P>90%)

νCOs-trans(cm-1) =1592.507(±9.455) – 31.421(±10.091)σI – 15.478(±5.977)σR …(35)

(R = 0.962, n=9, P>95%)

νCOs-trans(cm-1) =1590.993(± 9.792) – 27.047(±8.960)F – 14.654(± 5.265)R …(36)

(R = 0.957, n=9, P>90%)

νCHip (cm-1) =1202.531(±5.758) + 8.930(±3.624)σI + 7.676(±2.153)σR …(37)

(R = 0.942, n=9, P>90%)

νCHip (cm-1) = 1201.89 (±5.296) + 11.76 (±3.172) F + 8.73(±3.725) R …(38)

(R = 0.953, n=9, P>90%)

νCHop (cm-1) = 775.804(± 19.417) + 5.933(±3.233)σI - 39.788(± 11.004)σR …(39)

(R = 0.931, n=9, P>90%)

νCHop (cm-1) = 765.436(±16.981) + 22.938(±7.914)F - 43.544(±13.215)R …(40)

(R = 0.956, n=9, P>90%)

νCH=CHop (cm-1) = 1004.27(±15.944) + 17.22(±6.205)σI +33.68(±11.008) σR …(41)

(R = 0.977, n=9, P>95%)

νCH=CHop (cm-1) = 1010.401(±19.062) + 60.617(±21.955)F + 39.692(±13.672)R …(42)

(R = 0.964, n=9, P>90%)

νC=Cop (cm-1) = 535.337(± 30.013) + 17.433(±6.587)σI + 49.404(± 13.357)σR …(43)

(R = 0.933, n=9, P>90%)

νC=Cop (cm-1) = 534.365(±30.746) + 11.281(±3.576)F + 25.173(±8.073)R …(44)

(R = 0.922, n=9, P>90%)

121


Series-C

The assigned νCO modes of s-cis and s-trans conformers, CHip, CHop, CH=CHop

and C=Cop deformation modes with all the substituted styryl 3-cyanophenyl ketones in

series-C are presented in Table-7 and the respective conformers are shown in (36).

O

CN

H

H

X

O

CN

H

H

X

s-cis s-trans

(53)

The observed frequencies are correlated with different substituent constants

according to the approach of Jaffe133,152. The results of the statistical analysis158 are

shown in Table-10.

12

2

Ta

ble

- 1

0

The

re

su

lts o

f sta

tistical a

na

lysis

of

infr

are

d f

requ

en

cie

s ν

(cm

-1)

of

CO

s-c

is,

CO

s-t

rans ,

CH

ip, C

Hop,

CH

=C

Hop a

nd

C=

Cop m

od

es o

f

su

bstitu

ted s

tyry

l 3

-cya

no

he

nyl ke

tone

s (

Se

ries-C

) w

ith

H

am

me

tt c

on

sta

nts

σ, σ

+, σ

I & σ

R a

nd

F a

nd

R p

ara

me

ters

Fre

qu

en

cy

Co

nsta

nt

s

r I

ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Os-c

is(c

m-1

) σ

0

.915

16

54

.84

-5

.61

5.6

3

7

H,

3-B

r, 4

-Br,

2-C

l, 2

-OC

H3,

3-O

CH

3,

4-C

H3

σ

+

0.9

06

16

54

.33

-3

.48

5.6

7

7

H,

3-B

r, 4

-Br,

2-C

l, 2

-OC

H3,

3-O

CH

3,

4-C

H3

σ

I 0

.784

16

59

.74

-1

6.0

1

25

.45

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.6

54

16

53

.69

0

.97

25

.73

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.824

16

59

.79

-1

6.3

1

25

.48

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.810

16

51

.63

-9

.84

25

.60

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

νC

Os-t

rans(c

m-1

) σ

0

.820

15

97

.04

1

5.4

3

29

.31

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.9

32

15

96

.56

1

7.8

9

8.5

2

7

H,

3-B

r, 4

-Br,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.812

15

94

.60

1

5.7

6

29

.74

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.9

16

16

05

.60

3

2.4

0

8.9

2

7

H,

3-B

r, 4

-Br,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.813

15

95

.25

1

3.9

8

29

.81

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.824

16

05

.94

2

7.4

8

29

.09

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

Tab

le c

on

tinu

ed..

......

.

12

3

Tab

le c

on

tinu

ed..

.

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Hip

(cm

-1)

σ

0.8

04

11

15

.31

3

.54

35

.73

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.9

01

11

14

.56

6

.91

35

.58

6

H,

4-B

r, 2

-OC

H3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.801

11

17

.05

-2

.31

35

.76

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.8

26

11

22

.11

3

8.9

1

34

.49

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.818

11

16

.14

-0.0

3

35

.76

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.826

11

23

.19

3

6.4

5

34

.46

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

νC

Hop(c

m-1

) σ

0

.811

83

3.2

2

8.6

8

29

.13

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.8

03

83

5.7

1

-2.1

1

29

.32

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.831

82

0.1

3

38

.95

27

.85

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.8

01

83

4.9

4

-1.9

3

29

.34

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.831

81

7.6

8

45

.73

27

.54

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.805

83

4.0

8

-5.9

5

29

.30

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

12

4

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

H=

CH

op(c

m-1

) σ

0

.921

10

27

.09

-6

.61

2.0

3

7

3-B

r, 4

-Br,

3-C

l, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3, 4

-CH

3

σ

+

0.9

02

10

26

.83

-5

.61

1.9

9

7

3-B

r, 4

-Br,

3-C

l, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3, 4

-CH

3

σ

I 0

.839

03

3.4

3

-20

.31

11

.35

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.7

08

10

26

.27

4

.65

12

.28

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.864

10

34

.44

-2

3.1

4

11

.21

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.815

10

26

.95

7

.22

12

.18

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

νC

=C

op(c

m-1

) σ

0

.816

56

3.6

4

-21

.56

51

.64

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.8

32

56

6.0

8

-32

.83

49

.58

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.807

56

5.1

4

-16

.76

52

.22

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.8

08

56

1.6

0

19

.24

52

.17

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.812

57

0.1

1

-29

.88

51

.96

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.815

56

4.8

3

31

.89

51

.70

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

r

= c

orr

ela

tio

n c

oeff

icie

nt;

ρ

= s

lope

; I =

in

terc

ep

t;

s =

sta

nd

ard

devia

tio

n;

n

= n

um

be

r of

su

bstitu

en

ts.

125

From Table-10, the nCOs-cis frequencies (cm-1) with Hammett constants namely

σ (r = 0.915) and σ+(r = 0.906) have sown satisfactory correlations for all the

substituents except 3-Cl, 4-OCH3 and 3-NO2.

These three substituents namely 3-Cl, 4-OCH3 and 3-NO2 are reduce the

correlations considerably when these are included in regression.

The remaining Hammett constants namely σI & σR and F and R parameters have

shown poor correlations (r < 0.900) for all the substituents. This is due to the weak

inductive, resonance and field effects of the substituents for predicting the reactivity on

the carbonyl frequencies in all α,β-unsaturated ketones through resonance as per the

conjugative structure (47).

O

CN

H

H

O CH3

(47)

All the correlations have shown negative ρ values with Hammett constants and F

and R parameters except σR. This implies the operation of reverse substituent effects

for nCOs-cis frequencies (cm-1) in all α,β-unsaturated ketones belonging to Series-C.

The correlations of nCOs-trans frequencies (cm-1) with Hammett substituent

constants namely σ+ (r = 0.932) and σR (r = 0.906) have shown satisfactory correlations

for all substituents except 2-Cl, 3-Cl and 2-OCH3 substituents. These three substituents

126

namely 2-Cl, 3-Cl and 2-OCH3 reduce the correlations considerably when these are

included in regression.

The remaining Hammett σ and σI constants and F and R parameters have shown

poor correlations (r < 0.900) for all the substituents. This is due to the incapability of

polar, inductive, field and resonance effects of the substituents to transmit their

electronic effects on COs-trans conformers through resonance as per the conjugative

structure shown in (47).

All the correlations for νCOs-trans frequencies (cm-1) have shown positive ρ values

with Hammett constants and F and R parameters. This indicates the operation of

normal substituent effects in all α,β-unsaturated ketone belonging to series-C. Some of

the single regression linear plots are shown in Figures: (33)-(36).

127

Figure – 33: Plot of νCOs-cis(cm-1) of substituted styryl 3-cyanophenylphenyl ketones Vs σ

Figure – 34: Plot of νCOs-cis(cm-1) of substituted styryl 3-cyanophenylphenyl ketones Vs σ+


8. 4-OCH3 9. 4-CH3

10. 3-NO2


8. 4-OCH3 9. 4-CH3

10. 3-NO2

128

Figure – 35: Plot of νCOs-trans(cm-1) of substituted styryl 3-cyanophenylphenyl ketones Vs σ+

Figure - 36:

Plot of νCOs-trans(cm-1)of substituted styryl 3-cyanophenylphenyl ketones Vs σR


8. 4-OCH3 9. 4-CH3

10. 3-NO2


8. 4-OCH3 9. 4-CH3

10. 3-NO2

129

From Table-10, the νCHip deformation modes with Hammett constant σ+ has

shown satisfactory correlation (r = 0.901) for all substituents except 3-Br, 2-Cl, 3-Cl and

3-OCH3 substituents. These four substituents namely 3-Br, 2-Cl, 3-Cl and 3-OCH3

reduce the correlations considerably when these are included in regression. The

remaining Hammett constants namely σ, σI & σR and F and R parameters have shown

poor correlations (r < 0.900) for all substituents. This is due to weak inductive,

resonance and field effects of the substituents for predicting the reactivity on vinyl νCHip

deformation modes through resonance as per the conjugative structure shown in (47).

The correlations with νCHip deformation modes have shown positive ρ values

with Hammett constants and R parameter except σI and F parameter. This indicates

the operation normal substituent effect forl νCHip deformation modes in all

α,β-unsaturated ketones belonging to Series-C.

The Hammett constants namely σ, σ+, σI & σR and F and R parameters have

shown poor correlations (r < 0.900) with νCHop deformation modes for all substituents.

This is due to weak polar, inductive, resonance and field effects of the substituents for

predicting the reactivity on vinyl νCHop deformation modes through resonance as per


The correlations with νCHop deformation modes have shown positive ρ values for

Hammett constants such as σ & σI and F parameter. This indicates the operation

normal substituent effect for vinyl νCHop deformation modes in all α,β-unsaturated

ketones belonging to Series-C. Some of the single regression linear plots are shown in

Figures: (37)&(38).

130

Figure -37: Plot of νCHip(cm-1) of substituted styryl 3-cyanophenylphenyl ketones Vs σ+

Figure -38: Plot of νCHop(cm-1) of substituted styryl 3-cyanophenylphenyl ketones Vs σR


8. 4-OCH3 9. 4-CH3

10. 3-NO2


8. 4-OCH3 9. 4-CH3

10. 3-NO2

131


constants viz., σ (r = 0.921) and σ+ (r = 0.902) have shown satisfactory correlations for

all substituents except for parent member of this Series-C, 2-Cl and 3-NO2 substituents.

The parent compound of this series, 2-Cl and 3-NO2 substituents are reduce the


The remaining Hammett constants namely σI & σR and F and R parameters have

shown poor correlations (r < 0.900) with all the substituents. This is due to weak

inductive, resonance and field effects of the substituents to transmit their electronic

effects from phenyl rings to νCH=CHop deformation modes through resonance as per


The correlations of νC=Cop deformation modes with Hammett constants and

F and R parameters have shown poor correlations (r < 0.900) for all the substituents.

along with negative ρ values. This is due to weak polar, inductive, resonance and field

effects of the substituents to transmit their electronic effects on vinyl C=Cop deformation

modes in all α,β-unsaturated ketones through resonance as per the conjugative

structure shown in (47).

All the correlations for νCH=CHop and νC=Cop deformation modes have shown

negative ρ values with Hammett constants and F parameter except σR and R parameter.

This indicates the operation of reverse substituent effects in all α,β-unsaturated ketones

belonging to Series-C. Some of the single regression linear plots are shown in Figures:

(39)-(40).

132

Figure – 39: Plot of νCH=CHop

(cm-1) of substituted styryl 3-cyanophenylphenyl ketones Vs σ

Figure – 40: Plot of νCH=CHop

(cm-1) of substituted styryl 3-cyanophenylphenyl ketones Vs σ+


8. 4-OCH3 9. 4-CH3

10. 3-NO2


8. 4-OCH3 9. 4-CH3

10. 3-NO2

133


few Hammett constants and F and R parameters, it is decided to go for multi

regression analysis. The multi regression analysis of the stretching frequencies of all

α,β-unsaturated ketones with inductive, resonance and Swain – Lupton’s117

parameters produce satisfactory correlations as shown in equations (45)-(56):

νCOs-cis(cm-1) =1662.601(± 9.015) – 19.823(± 7.233)σI + 8.995(± 2.404) σR …(45)

(R = 0.916, n=10, P>90%)

νCOs-cis(cm-1) =1657.936(± 2.684) – 13.864(± 4.394)F – 4.766(± 1.063)R …(46)

(R = 0.914, n=10, P>90%)

νCOs-trans(cm-1) =1604.491(± 21.663) + 2.464(± 0.432)σI + 31.405( ± 11.483)σR …(47)

(R = 0.956, n=10, P>90%)

νCOs-trans(cm-1) =1606.058(± 23.634) – 0.232(± 0.158)F + 27.564(± 8.934)R …(48)

(R = 0.942, n=9, P>90%)

νCHip (cm-1) =1132.356(± 25.573) - 22.767(± 6.094)σI + 48.133(± 15.984) σR …(49)

(R = 0.929, n=10, P> %)

νCHip (cm-1)=1133.743(± 27.745) - 23.198(± 4.183)F + 44.951(± 12.692)R …(50)

(R = 0.929, n=10, P> %)

νCHop (cm-1=813.354(±20.568) + 47.969(± 15.283)σI - 21.366(±6.386) σR …(51)

(R = 0.935, n=10, P> %)

νCHop (cm-1) =806.713(±21.722) + 60.168(±21.427)F - 27.991(±8.764)R …(52)

(R = 0.941, n=10, P> %)

νCH=CHop (cm-1) = 1038.373(±8.115) – 26.884(±8.883) σI + 15.538(± 4.538) σR …(53)

(R = 0.947, n=10, P> %)

νCH=CHop (cm-1)=1042.021(±8.326) - 33.126(±11.258)F + 19.369(± 6.702)R …(54)

(R = 0.955, n=10, P> %)

νC=Cop(cm-1) = 557.941(±13.431) +18.798 (± 2.661) σI –34.713 (± 2.417) σR ...(55)

(R =0.945, n = 12, P > 90%)

νC=Cop(cm-1) = 560.223(±12.750) +14.012 (±3.421)F –25.157 (±7.205)R ...(56)

(R = 0.940, n = 12, P> 90%)

134


Series-D

The s-cis and s-trans conformers of substituted styryl 2-pyrrolyl ketones in

Series-D are shown in (54) and the corresponding stretching frequencies are presented

in Table-7.

(54)

NH

O

NH

O

X

X

These frequencies are correlated with different substituent constants and F and

R parameters according to the approach of Jaffe133,152. The results of the statistical

analysis158 are presented in Table-11.

13

5

Ta

ble

- 1

1

The

re

su

lts o

f sta

tistical a

na

lysis

of

infr

are

d f

requ

en

cie

s ν(c

m-1

) of

CO

s-c

is,

CO

s-t

rans ,

CH

ip, C

Hop,

CH

=C

Hop a

nd

C=

Cop m

od

es o

f su

bstitu

ted

sty

ryl 2

-pyrr

oly

l ke

ton

es (

Se

rie

s-D

) w

ith

H

am

me

tt c

on

sta

nts

σ, σ

+, σ

I &

σR

an

d F

and

R p

ara

me

ters

Tab

le c

on

tinu

ed..

.

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Os-c

is(c

m-1

) σ

0

.943

16

45

.91

3.3

73

0.6

0

11

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 3

-OC

H3,

4-O

CH

3,

4-C

H3,

3

-NO

2, 4

-NO

2,

σ

+

0.8

17

16

46

.15

2.2

31

2.6

6

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

I 0

.713

16

45

.03

3.7

95

2.7

4

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

R

0.8

35

16

47

.39

3.9

41

2.7

0

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.827

16

45

.24

2.9

53

2.7

8

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

R

0

.834

16

47

.42

3.3

85

2.7

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

νC

Os-t

rans(c

m-1

) σ

0

.730

15

97

.31

18

.85

1

22

.22

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

+

0.7

34

15

98

.24

15

.97

1

21

.09

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

I 0

.830

15

82

.03

19

.58

3

48

.80

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

R

0.8

13

15

97

.71

-6.7

06

23

.15

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.858

15

79

.19

51

.44

8

18

.75

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

R

0

.811

15

97

.81

-9.0

11

23

.20

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

13

6

T

ab

le c

on

tinu

ed

...

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Hip

(cm

-1)

σ

0.8

62

11

33

.00

-36

.031

16

.97

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

+

0.8

71

11

31

.28

-30

.670

15

.24

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

I 0

.712

11

33

.72

-17

.739

27

.39

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

R

0.8

59

11

15

.39

-49

.652

17

.50

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.806

11

29

.04

-4.8

75

21

.77

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

R

0

.806

11

13

.33

-48

.880

16

.27

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

νC

Hop(c

m-1

) σ

0

.728

85

3.1

0

11

.87

2

15

.11

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

+

0.8

35

85

3.5

9

10

.89

4

14

.76

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

I 0

.833

84

6.8

0

21

.90

4

14

.86

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

R

0.8

01

85

5.0

6

0.0

41

1

15

.77

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.838

84

5.6

8

22

.70

4

14

.52

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

R

0

.803

85

5.5

7

1.7

61

15

.76

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

13

7

r =

co

rre

latio

n

co

eff

icie

nt;

ρ

=

slo

pe

; I

=

Inte

rce

pt;

s

=

sta

nd

ard

d

evia

tio

n;

n

=

n

um

be

r of

su

bstitu

en

ts.

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

H=

CH

op(c

m-1

) σ

0

.704

10

58

.00

2.4

55

18

.96

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

+

0.7

25

10

85

.56

1.0

98

18

.97

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

I 0

.822

10

51

.76

17

.60

8

18

.50

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

R

0.8

16

10

61

.95

11

.70

0

18

.73

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

F

0

.810

10

56

.66

5.6

81

18

.92

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

R

0

.817

10

61

.68

11

.49

2

18

.67

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

νC

=C

op(c

m-1

) σ

0

.711

54

7.2

2

6.3

81

21

.77

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

+

0.6

13

57

2.9

8

1.3

01

21

.40

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

I 0

.816

56

7.6

9

14

.50

1

21

.12

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

R

0.9

40

56

5.4

9

32

.75

0

5.6

1

8

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

2-O

CH

3,

4-O

CH

3,

3-N

O2

F

0

.821

56

6.4

9

16

.71

1

20

.93

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

R

0

.836

56

5.6

6

26

.40

0

19

.99

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

138

From Table-11, the stretching frequencies νCOs-cis (cm-1) with Hammett constant

σ has shown satisfactory correlation (r = 0.943) for all the substituents except 2-OCH3. If

the substituent 2-OCH3 is included in regression this reduces the correlations

considerably. The remaining Hammett constants namely σ+, σI & σR and F and R

parameters have shown poor correlation (r < 0.900) for νCOs-cis stretching frequencies

(cm-1) for all the substituents.

This is due to the weak polar, inductive and resonance effects of the substituents

for predicting the reactivity on carbonyl frequencies of all α,β-unsaturated ketones


NH

O

O

CH3

(48)

H

H

However the νCOs-trans frequencies (cm-1) with Hammett constants and F and R

parameters have shown poor correlations (r < 0.900) for all the substituents. This is due

to the weak polar, inductive and resonance effects of the substituents for predicting the

reactivity on carbonyl frequencies of all α,β-unsaturated ketones through resonance as

per the conjugative structure shown in (48).

The correlations of both the νCOs-cis and νCOs-trans frequencies (cm-1) have shown

positive ρ values with Hammett constants and F and R parameters. This indicates the

operation of normal substituent effects in all α,β-unsaturated ketones belonging to

Series-D. Some of the single linear plots are shown in Figures: (41) & (42).

139

Figure – 41:

Plot of νCOs-cis(cm-1) of substituted styryl 2-pyrrolylphenyl ketones Vs σ

Figure – 42:

Plot of νCOs-trans(cm-1) of substituted styryl 2-pyrrolylphenyl ketones Vs σ

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

140

From Table-11, the νCHip and νCHop deformation modes of 2-pyrroly

α,β-unsaturated ketones with Hammett substituent constants namely σ, σ+, σI & σR and

F and R parameters have shown poor correlation (r < 0.900) for all the substituents.

This is due to the weak polar, inductive, resonance and field effect of the

substituents for predicting the reactivity on vinyl νCHip and νCHop deformation modes


The correlations of νCHip deformation modes have shown negative ρ values with

Hammett constants and F and R parameters. This indicates the operation of reverse

substituent effects in all α,β-unsaturated ketones.

But the correlations of νCHop deformation modes have shown positive ρ values

with Hammett substituent constants and F and R parameters. It indicates the operation

of normal substituent effect in all α,β-unsaturated ketones belonging to series-D.

From Table-11, the νCH=CHop deformation modes with Hammett constants


for all the substituents. This is due to the incapability of polar, inductive, resonance and

filed effects of the substituents to transmit their electronic effects to vinyl carbons


The correlations of νCH=CHop deformation modes have shown positive ρ values

with Hammett constants and F and R parameters except σ+ constant. It implies the

operation of normal substituent effects for νCH=CHop deformation modes in all

α,β-unsaturated ketones belonging to Series-D.

141

In case of νC=Cop deformation modes, the Hammett substituent constant σR has

shown satisfactory correlation (r = 0.940) for all the substituents except 4-F, 3-OCH3,

4-CH3 and 4-NO2 substituents. These four substituents namely 4-F, 3-OCH3, 4-CH3 and

4-NO2 substituents reduce the correlations considerably when these are included in

regression analysis.

The remaining Hammett constants namely σ, σ+ & σI and F and R parameters

have shown poor correlations (r < 0.900) for all substituents.

This is due to weak polar, inductive and field effect of the substituents for

predicting the reactivity on νC=Cop deformation modes in all α,β-unsaturated ketones


All the correlations have shown positive ρ values with Hammett constants and

F and R parameters except σ & σI and F parameter. It indicates the operation of normal

substituent effect in all α,β-unsaturated ketones belonging to Series-D. Some of the

single regression linear plots are shown in Figures: (43) & (44).

142

Figure – 43: Plot of νC = Cop (cm-1) of substituted styryl 2-pyrrolylphenyl ketones Vs σR

Figure - 44: Plot of νC = Cop (cm-1) of substituted styryl 2-pyrrolylphenyl ketones Vs σ

1. H2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

143





parameters produce satisfactory correlations as shown in equations (57)-(68).

νCOs-cis(cm-1) = 1646.04(±1.815) + 3.351(±0.359) σI + 3.594(±0.330) σR ...(57)

(R = 0.945, n = 12, P > 90%)

νCOs-cis(cm-1) = 1646.13(±1.668) +3.348(±0.316)F +3.683(±0.278)R ...(58)

(R = 0.942, n = 12, P > 90%)

νCOs-trans(cm-1) =1577.25(±13.851)+50.906(±17.444)σI - 17.000(±2.518) σR ...(59)

(R = 0.953, n = 12, P > 95%)

νCOs-trans(cm-1) = 1578.12(±12.189)+50.968(±16.147)F –4.467(±2.108)R ...(60)

(R = 0.959, n = 12, P > 95%)

νCHip(cm-1) = 1120.12(±12.152) -11.750(±2.401) σI-48.428(±2.281) σR ...(61)

(R =0.961, n = 12, P > 95%)

νCHip(cm-1) = 1117.10(±10.455) -10.228(±3.851)F -49.799(±1.801)R ...(62)

(R = 0.967, n = 12, P> 95%)

νCHop(cm-1) = 846.142(±10.441) + 22.196(±2.269) σI-2.361(±0.187) σR ...(63)

(R = 0.933, n = 12, P > 90%)

νCHop(cm-1) = 846.60(±9.431) + 23.117(±8.921)F + 3.822(±1.673)R ...(64)

(R =0.939, n = 12, P > 90%)

νCH=CHop(cm-1) = 1054.57(±12.881) +16.372(±2.558) σI+10.000(±2.314)σR...(65)

(R = 0.926, n = 12, P > 90%)

νCH=CHop(cm-1) = 1058.97(±12.110) + 6.986(±2.229)F +12.115(±2.094)R ...(66)

(R = 0.920, n = 12, P> 90%)

νC=Cop(cm-1) = 557.941(±13.431) +18.798(±2.661) σI-34.713(±2.417) σR ...(67)

(R =0.945, n = 12, P > 90%)

νC=Cop(cm-1) = 560.22(±12.750) +14.012(±2.421)F –25.157(±2.205)R ...(68)

(R = 0.940, n = 12, P> 90%)

144


Series-E

The assigned νCOs-trans and νCOs-cis conformers and the deformation modes of

νCHip, νCHop, νCH=CHop and νC=Cop in all the substituted styryl 3-methylphenyl ketones

in series-E are presented in Table-7 and the corresponding conformers are shown in

(55).

O

CH3

H

H

X

O

CH3

H

H

Xs-cis s-trans

(55)

The observed frequencies are correlated with different substituent constants and

F and R parameters according to the approach of Jaffe133,152. The results of the

statistical analysis158 are presented in Table-12.

14

5

Ta

ble

- 1

2

The

re

su

lts o

f sta

tistical a

na

lysis

of

infr

are

d f

requ

en

cie

s ν

(cm

-1)

of

CO

s-c

is, C

Os-t

rans ,

CH

ip,

CH

op,

CH

=C

Hop a

nd

C=

Cop m

ode

s o

f

su

bstitu

ted s

tyry

l 3

-meth

ylp

he

nyl ke

tone

s (

Serie

s-E

) w

ith

H

am

me

tt c

on

sta

nts

σ,

σ+,

σI &

σR

and

F a

nd

R p

ara

me

ters

Tab

le c

on

tinu

ed..

.

Fre

qu

en

cy

Co

nsta

nt

s

r I

ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Os-c

is(c

m-1

) σ

0

.753

16

74

.17

-16

.72

8.6

6

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.7

60

16

73

.74

-16

.24

8.1

7

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.765

16

79

.59

-24

.98

7.7

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.7

03

16

69

.61

1.9

0

10

.26

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.761

16

78

.87

-22

.47

8.0

8

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.702

16

69

.55

0.9

7

10

.26

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

νC

Os-t

rans(c

m-1

) σ

0

.905

15

61

.35

83

.25

3.9

2

6

H,

4-C

l,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.9

06

15

63

.68

80

.09

3.4

9

6

H,

4-C

l,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.806

15

37

.34

11

7.2

8

36

.53

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.9

02

15

85

.70

6.2

4

4.4

2

6

H,

4-C

l,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.802

15

99

.33

0.3

75

15

.07

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.910

16

00

.12

4.2

3

4.9

7

6

H,

4-C

l,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

14

6

Tab

le c

on

tinu

ed..

.

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

Hip

(cm

-1)

σ

0.8

11

11

70

.12

-3

.23

9.2

1

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.7

18

11

70

.42

-4

.57

9.1

0

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.836

11

74

.27

-1

2.4

7

8.6

3

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.8

34

11

70

.84

1

5.5

6

8.6

9

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.836

11

74

.22

-1

1.9

2

8.6

4

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.835

11

74

.22

-1

1.9

2

8.6

4

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

νC

Hop(c

m-1

) σ

0

.911

77

7.8

1

23

.35

8.9

9

7

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3

σ

+

0.9

22

79

0.0

8

13

.60

9.9

6

7

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-NO

2

σ

I 0

.714

78

5.0

0

17

.65

31

.37

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.8

55

83

0.8

0

20

.37

36

.52

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.817

77

9.8

3

28

.29

39

.81

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.951

83

4.4

2

11

.76

8.8

3

8

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

4-N

O2

14

7

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

νC

H=

CH

op(c

m-1

) σ

0

.710

10

17

.19

-12

.87

4.5

3

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.8

14

10

17

.56

-15

.11

4.3

4

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.747

10

42

.55

-21

.36

3.8

7

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.9

05

10

24

.89

17

.63

1.2

0

8

3-B

r, 4

-Br,

3-C

l, 4

-Cl, 4

-F,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.847

10

42

.68

-29

.23

3.8

0

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.905

10

27

.98

17

.02

1.6

0

8

3-B

r, 4

-Br,

3-C

l, 4

-Cl, 4

-F,

4-C

H3,

3-N

O2, 4

-NO

2

νC

=C

op(c

m-1

) σ

0

.803

55

0.6

3

-3.6

0

37

.37

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.8

13

55

3.1

8

-13

.40

37

.04

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.840

57

2.2

6

-35

.71

34

.30

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.7

33

55

5.9

6

20

.21

35

.27

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.748

57

6.5

0

-33

.88

32

.78

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.735

55

7.9

4

36

.02

34

.94

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s =

sta

nd

ard

de

via

tio

n; n

= n

um

be

r of

su

bstitu

en

ts.

148

From Table-12, the νCOs-cis frequencies (cm-1) with Hammett substituent


(r < 0.900) for all the substituents. This is due to the incapablility of polar, inductive,

resonance and field effects of the substituents to transmit their electronic effect from

phenyl rings to carbonyl groups through resonance as per the conjugative

structure (49).

O

CH3

H

H

CH2

H

(49)


parameter except σR and R parameter. This indicates the operation of reverse

substituent effects on COs-cis conformers in all α,β-unsaturated ketones belonging to

Series-E.

The νCOs-trans frequencies (cm-1) with Hammett constants namely σ (r < 0.905),

σ+ (r < 0.906) & σR (r < 0.902) and R (r < 0.910) parameter have shown satisfactory

correlations for all the substituents except 3-Br, 4-Br and 3-Cl substituents. These three

substituents namely 3-Br, 4-Br and 3-Cl reduce the correlations considerably when

these are included in regression analysis.

The remaining Hammett constant σI and F parameter have shown poor

correlations (r < 0.900) for all the substituents. This is due the capability of inductive and

field effects of the substituents to transmit their electronic effect from phenyl rings to

carbonyl groups through resonance as per the conjugative structure (49). All of the

149

correlations have shown positive ρ values with Hammett constants and F and R

parameters. This indicates the operation of normal substituent effect in all

α,β-unsaturated ketones belonging to Series-E. Some of the single regression linear

plots are shown in Figures: (45) - (48).

Figure – 45: Plot of νCOs-trans(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs σ

Figure – 46:

Plot of νCO s-trans(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs σ+



150

Figure – 47: Plot of νCOs-trans(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs σR

Figure – 48:

Plot of νCO s-trans(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs R



151

From Table-12, the νCHip deformation modes with Hammett constants namely σ,

σ+, σI & σR and F and R parameters have shown poor correlations (r < 0.900) for all the

substituents. This is due the weak polar, inductive, resonance and field effects of

substituents for predicting the reactivity on vinyl deformation modes through resonance

as per the conjugative structure shown in (49).

All the correlastions of νCHip deformation modes have shown negative ρ values

with Hammett constants and F and R parameters except σR constant. This indicates

the operation of reverse substituent effects in all α,β-unsaturated ketones belonging to

Series-E.

However the νCHop deformation modes with Hammett constants namely

σ (r = 0.911) & σ+ (r = 0.922) and R (r = 0.951) parameter have shown satisfactory

correlations. All the substituents except 3-NO2 and 4-NO2 have shown satisfactory

correlations with Hammett constants namely σ and σ+. The R parameter has also

shown satisfactory correlation with νCHop deformation modes for all the substituents

except 3-NO2. These two substituents namely 3-NO2 and 4-NO2 reduce the


The remaining Hammett constants namely σI & σR and F parameter have shown

poor correlations (r = 0.900) for all the substituents.This is due to the weak inductive,

resonance and polar effects of the substituents for predicting the reactivity on vinyl

νCHop deformation modes through resonance as the conjugative structure shown in

(49).

The correlations of νCHop deformation modes have shown positive ρ values with

Hammett constants and F and R parameters. This reveals the operation of normal

substituent effects in all α,β-unsaturated ketones belonging to Series-E. Some of the

single regression linear plots are shown in Figures: (49)-(52).

152

Figure - 49: Plot of νCHop(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs σ

Figure – 50: Plot of νCHop(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs σ+



153

Figure - 51:

Plot of νCHop(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs R

Figure – 52:

Plot of νCHop(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs σI



154


constant σR (r = 0.905) and R (r = 0.905) parameter have shown satisfactory

correlations for all the substituents except parent compound (H) of this Series-E. This

parent compound (H) reduces the correlations considerably when this is included in

regression.

The remaining Hammett constants namely σ, σ+ & σI and F parameter have

shown poor correlations (r < 0.900) for all the substituents. This is due to the incapability

of polar, inductive and field effect of the substituents to transmit their electronic effects

from phenyl rings to vinyl νCH=CHop deformation modes through resonance as per the

conjugative structure shown in (49).

The νC=Cop deformation modes with Hammett constants namely σ, σ+, σI & σR

and F and R parameters have shown poor correlations (r < 0.900) for all the

substituents. This is due to weak polar, inductive, resonance and field effects of the

substituents for predicting the reactivity on vinyl νC=Cop deformation modes through


All the correlations for both νCH=CHop and νC=Cop deformation modes have

shown negative ρ values with Hammett constants and F parameter except σR and R

parameter. This indicates the operation of reverse substituent effects for both the

νCH=CHop and νC=Cop deformation modes in all α,β-unsaturated ketones belonging to

Series-E. Some of the single regression linear plots are shown in Figures: (53)-(54).

155

Figure – 53: Plot of νCH=CHop(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs σR

Figure – 54: Plot of νCH=CHop(cm-1) of substituted styryl 3-methylphenylphenyl ketones Vs R



156





parameters produce satisfactory correlations as shown in equations (69)-(80).

νCOs-cis (cm-1) = 1680.010(±5.75) – 25.125(±6.57)σI + 3.559(±1.24)σR …(69)

(R = 0.966, n=9, P>95%)

νCOs-cis (cm-1) = 1678.575(±5.86) – 22.856(±5.82) F – 3.072(±1.99)R …(70)

(R = 0.961, n=9, P>95%)

νCOs-trans(cm-1)= 1537.154 (±27.39) + 117.355 (±24.07) σI –1.626 (±0.50)σR …(71)

(R = 0.965, n=9, P>95%)

νCOs-trans(cm-1)= 1547.396 (±28.64) + 100.840 (±22.70) F + 32.371(±8.31) R …(72)

(R = 0.958, n=9, P>90%)

νCHip (cm-1)=1176.263(±5.958) – 13.105(±2.971) σI + 16.646 (±5.763) σR …(73)

(R = 0.951, n=9, P>90%)

νCHip (cm-1) =1175.936(±6.054) – 10.654(±2.191)F + 10.105(±3.438)R …(74)

(R = 0.944, n=9, P>90%)

νCHop (cm-1) =815.062(±56.863) +38.065(±11.296)σI +247.825(±95.479)σR …(75)

(R = 0.956, n=9, P>90%)

νCHop (cm-1) =800.583(±54.729) + 85.735(±11.237)F + 216.560(±94.498)R …(76)

(R = 0.958, n=9, P>90%)

νCH=CHop (cm-1)=1053.227(±25.282)+ 59.913(±15.238)σI –136.876(±47.015)σR …(77)

(R = 0.959, n=9, P>90%)

νCH=CHop (cm-1)=1050.987(±21.445) – 58.271 (±13.187)F +86.690(±27.113)R …(78)

(R = 0.969, n=9, P>95%)

νC = Cop (cm-1)=580.052(±23.675) – 58.203(±17.517)σI +64.126(±23.633)σR …(79)

(R = 0.953, n=9, P>90%)

νC = Cop (cm-1)=580.883(±22.565) – 58.105(±15.447)F + 45.739(±14.796)R …(80)

(R = 0.956, n=9, P>90%)

157

1.3.3 CORRELATION ANALYSIS OF NMR SPECTRAL DATA OF

α, β - UNSATURATED KETONES

1.3.3.1 CORRELATION ANALYSIS OF 1H NMR SPECTRAL DATA OF

α, β - UNSATURATED KETONES

The 1H NMR spectra of synthesized α,β-unsaturated ketones in the present

investigation are recorded in CDCl3 using tetramethylsilane (TMS) as internal standard.

The signals of the ethylenic protons have been assigned. They are calculated as AB or

AA' BB' systems respectively. The chemical shifts of Hα are at higher field than those of

Hβ in the series (A to E) are investigated (44).

158

R

O

X

R X

OCH3

H3CO

H3CO

Br

CN

A

B




NH

CH3

D

E


H, 3-Br, 4-Br, 3-Cl, 4-Cl, 4-F, 4-CH3, 3-NO2, 4-NO2

C

44

Series

The ethylenic protons gives an AB pattern and the β proton doublet in most

cases is well separated from aromatic protons.

159

HA

Y HB

HC

(56)

The system investigated is comparable to the one handled by Charton159 which is

shown as in (56).

In the present investigation, Y-is replaced by 3,4,5-trimethoxyphenyl,

3-bromophenyl, 3-cyanophenyl, 2-pyrrolyl and 3-methylphenyl keto group and one of the

β protons is replaced by a substituted phenyl group to get (44).

Charton159 employed the technique of single and multiple correlations for simple vinyl

derivatives and indicated that there was no useful correlation for Hα, but only a moderately

good correlation for the trans-vicinal Hβ proton. Solcaniova and Toma129,130 investigated the

effect of substituents on 1H NMR spectra of α,β-unsaturated ketones.

In their investigations, the Hα chemical shifts are most sensitive to the substituent

effects. Further Solcaniova and Toma129,130 observed opposite sign of the slopes for Hα

and Hβ in their correlations of chemical shifts with substituent constants. That was

attributed by them to the polarization of the C=O double bond being predominantly

caused by the carbonyl group.

The general structure of all the synthesized α,β-unsaturated ketones are

shown in (44) with the incorporation of 3,4,5-trimethoxyphenyl, 3-bromophenyl,

3-cyanophenyl, 2-pyrrolyl and 3-methylphenyl groups in the place of R in (44). The

recorded 1H NMR spectra of all α,β-unsaturated ketones of all the series (A to E)

without substituents are shown in Figures: (55)-(59).

16

0

Fig

ure

-55

: 1

H N

MR

Sp

ectr

um

of

sty

ryl-3

,4,5

-trim

eth

oxyp

he

nyl k

eto

ne

(S

erie

s-A

)

O

OC

H3

H3C

O

H3C

O

16

1

Fig

ure

-56

: 1

H N

MR

Sp

ectr

um

of

sty

ryl-3

-bro

mo

ph

en

yl ke

ton

E (

Se

rie

s-B

)

O

Br

16

2

Fig

ure

-57

: 1

H N

MR

Sp

ectr

um

of

sty

ryl-3

-cya

no

ph

en

yl ke

ton

e (

Se

rie

s-C

)

O

CN

16

3

Fig

ure

-58

: 1

H N

MR

Sp

ectr

um

of

sty

ryl-2

-pyrr

oly

l ke

ton

e (

Se

rie

s-D

)

O

N H

16

4

Fig

ure

-59

: 1

H N

MR

Sp

ectr

um

of

sty

ryl-3

-me

thylp

he

nyl ke

ton

e (

Se

rie

s-E

)

O

CH

3

165

The assigned 1H NMR spectral data of δHα and δHβ of the substituted styryl


ketones are presented in Table-13.

Table-13

The 1H NMR spectral chemical shifts δ(ppm) of Hα and Hβ protons of the substituted

styryl 3,4,5-trimethoxyphenyl (Series-A), 3-bromophenyl (Series-B),

3-cyanophenyl(Series-C), 2-pyrrolyl (Series-D) and 3-methylphenyl ketones (Series-E)

Table continued...

Series-A: Substituted styryl 3,4,5-trimethoxyphenyl ketones

Sl.No. Substituent δHα (ppm) δHβ (ppm)

1 H 7.33 7.75

2 3-Br 7.42 7.74

3 4-Br 6.94 7.68

4 2-F 6.94 7.64

5 2-OCH3 6.95 7.60

6 4-OCH3 7.35 7.78

7 2-CH3 7.32 8.08

8 4-CH3 7.42 7.73

9 4-NO2 7.52 7.76


1 H 7.38 7.94

2 2-Br 7.35 7.90

3 2-Cl 7.39 7.89

4 4-Cl 7.70 7.93

5 4-F 7.72 7.94

6 4-CH3 7.70 7.94

7 2-OCH3 7.55 8.11

8 4-OCH3 7.62 7.93

9 3-NO2 7.87 8.08

166

Table continued...



1 H 7.49 7.88

2 3-Br 7.15 7.69

3 4-Br 7.28 7.78

4 2-Cl 7.37 7.83

5 3-Cl 7.43 7.89

6 2-OCH3 7.47 7.86

7 3-OCH3 7.52 8.16

8 4-OCH3 7.47 8.06

9 4-CH3 7.45 7.67

10 3-NO2 7.61 7.98


1 H 7.1 7.84

2 2-Cl 7.16 7.69

3 3-Cl 7.11 7.74

4 4-Cl 7.09 7.76

5 3-F 7.08 7.86

6 4-F 7.29 7.85

7 2-OCH3 7.25 7.79

8 3-OCH3 7.27 7.82

9 4-OCH3 7.27 7.83

10 4-CH3 7.31 7.8

11 3-NO2 7.44 7.84

12 4-NO2 7.38 7.79

167

1.3.3.1.1 Correlation analysis of 1H NMR spectral data of α,β-unsaturated

ketones in Series-A

The observed 1HNMR chemical shifts (ppm) of δHα and δHβ of substituted styryl

3,4,5-trimethoxyphenyl ketones in series-A are presented in Table-13. These chemical

shift δ(ppm) values are correlated with Hammett substituent constants and F and R

parameters160,161. The results of statistical analysis158 are shown in Table-14.



1 H 7.56 7.84

2 3-Br 7.32 7.74

3 4-Br 7.33 7.74

4 3-Cl 7.25 7.75

5 4-Cl 7.24 7.74

6 4-F 7.43 7.79

7 4-CH3 7.51 7.78

8 3-NO2 7.34 7.85

9 4-NO2 7.51 8.16

16

8

Ta

ble

- 1

4

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

1H

NM

R o

f δ

Hα a

nd

δH

β (

pp

m)

of

su

bstitu

ted

sty

ryl 3

,4,5

-th

rim

eth

oxyp

he

nyl

ke

tone

s (

Se

rie

s-A

) w

ith

Ha

mm

ett

co

nsta

nts

σ,

σ+, σ

I & σ

R a

nd

F a

nd

R p

ara

mete

rs

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n;

n=

num

be

r of

sub

stitu

en

ts.

Ch

em

ica

l S

hifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δHα(p

pm

) σ

0

.934

7.2

21

0.2

31

0.1

31

6

H,

3-B

r, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.9

14

7.2

30

0.0

81

0.1

50

6

H,

3-B

r, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.810

7.2

91

0.1

90

0.2

41

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.9

06

7.3

84

0.6

65

0.1

84

6

H,

3-B

r, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.823

7.3

23

0.2

55

0.2

43

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4-C

H3, 4

-NO

2

R

0

.963

7.3

98

0.5

77

0.1

98

6

H,

3-B

r, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

δHβ(p

pm

) σ

0

.807

7.7

56

-0.0

22

0.1

46

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.8

15

7.7

61

-0.0

51

0.1

42

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.646

7.8

25

-0.2

51

0.1

33

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.7

35

7.7

93

-0.2

71

0.1

42

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.748

7.8

31

-0.2

48

0.1

32

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.735

7.8

00

-0.1

99

0.1

41

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

169

From Table-14, the δHα chemical shifts (ppm) with Hammett σ (r = 0.934),

σ+ (r = 0.914) and σR (r = 0.906) constants and R (r = 0.963) parameter have shown

satisfactory correlations for all the substituents except 4-Br, 2-F and 2-OCH3

substituents. These three substituents namely 4-Br, 2-F and 2-OCH3 reduce the



correlations (r < 0.900) for all the substituents. This is due to the weak inductive and

field effects of the substituents for predicting the reactivity on the vinyl Hα proton

chemical shifts through resonance as per conjugative structure (45).

O

OCH3

H3CO

H3CO

O

CH3

(45)

H

H

All the correlations for δHα (ppm) chemical shifts have shown positive ρ values

with Hammett constants and F and R parameters. It indicates the operation of normal

substituent effects on δHα (ppm) chemical shifts in all α,β-unsaturated ketones

belonging to series-A.

But in case of δHβ chemical shifts, the Hammett constants namely σ, σ+, σI & σR

and F and R parameters have shown poor correlations (r < 0.900) for all the


substituents for predicting the reactivity on vinyl Hα proton chemical shifts through


The correlations of δHβ chemical shifts have shown negative ρ values with

Hammett constants and F and R parameters. This indicates the operation of reverse

170

substituent effects in all α,β-unsaturated ketones belonging to Series-A. Some of the

single regression linear plots are shown in Figures: (60) - (63).

Figure – 60:

Plot of δHα(ppm) of substituted styryl 3,4,5-trimethoxyphenylphenyl ketones Vs σ

Figure – 61:

Plot of δHα(ppm) of substituted styryl 3,4,5-trimethoxyphenylphenyl ketones Vs σ+

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

171

Figure – 62: Plot of δHα(ppm) of substituted styryl 3,4,5-trimethoxyphenylphenyl ketones Vs σR

Figure – 63: Plot of δHα(ppm) of substituted styryl 3,4,5-trimethoxyphenylphenyl ketones Vs R

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

172

Since most of the single regression analyses have shown poor correlations with


regression analysis of chemical shifts of δHα and δHβ (ppm) of all α,β-unsaturated

ketones with inductive, resonance and with Swain-Lupton’s117 parameters have shown


δHα(ppm) = 7.442(±0.116) – 0.196(±0.264) σI + 0.665(±0.282) σR …(81)

(R = 0.971, n=9, P>95%)

δ Hα (ppm) = 7.433(±0.121) – 0.145(±0.262) F + 0.541(±0.287) R …(82)

(R = 0.965, n=9, P>95%)

δHβ(ppm) = 7.865(±0.084) – 0.242(±0.186) σI + 0.205(±0.198) σR …(83)

(R = 0.958, n=9, P>90%)

δHβ(ppm) = 7.864(±0.087) – 0.215(±0.175) F + 0.147(±0.184) R …(84)

(R = 0.954, n=9, P>90%)


ketones in Series-B

The assigned 1H NMR chemical shifts (ppm) of Hα and Hβ of substituted styryl

3-bromophenyl ketones in series-B are presented in Table-13. These chemical shifts

are correlated with Hammett substituent constants and F and R parameters160,161. The

results of statistical analysis158 with these chemical shifts (ppm) are shown in

Table-15.

17

3

Ta

ble

- 1

5

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

1H

NM

R o

f δ

Hα a

nd

δH

β (

pp

m)

of

su

bstitu

ted s

tyry

l 3

-bro

mo

ph

en

yl ke

ton

es (

Serie

s-B

) w

ith

Ha

mm

ett c

on

sta

nts

σ,

σ+, σ

I & σ

R, F

and

R

pa

ram

ete

rs

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δHα(p

pm

) σ

0

.923

7.5

80

0.0

76

0.0

92

6

4-C

l, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.9

13

7.5

85

-0.0

62

0.0

91

6

4-C

l, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.824

7.5

21

0.1

93

0.1

88

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.9

09

7.6

03

0.0

62

0.0

93

6

4-C

l, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.831

7.4

92

0.2

61

0.1

80

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.932

7.5

65

-0.0

66

0.0

94

6

4-C

l, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

δHβ(p

pm

) σ

0

.811

7.9

61

0.0

23

0.1

81

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.9

03

7.9

62

0.0

04

0.0

80

7

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 3

-NO

2

σ

I 0

.824

7.9

38

0.0

73

0.1

83

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.8

03

7.9

69

0.0

13

0.1

87

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.815

7.9

42

0.0

48

0.1

82

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.711

7.9

73

0.0

31

0.2

88

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n; n

= n

um

be

r of

su

bstitu

ents

.

174

From Table-15, the Hammett constants namely σ (r = 0.923), σ+ (r = 0.913), σR

(r = 0.909) and R (r = 0.932) parameter have shown satisfactory correlations with

δHα chemical shifts (ppm) for all the substituents except parent compound (H) of this

series-B, 2-Br and 2-Cl substituents. The parent compound and the substituents

namely 2-Br and 2-Cl reduce the correlations considerably when these are included in

regression.


correlations (r < 0.900) for all the substituents. This is due to the incapablility of

inductive and field effects of the substituents for predicting the reactivity on vinyl

protons through resonance as per the conjugative structure (46).

O

Br

H

H

O

(46)

CH3

All the correlations have shown positive ρ values with Hammett constants and F

parameter except σ+ and R parameter. It indicates the operation of normal substituent

effects on δHα chemical shifts (ppm) in all α,β-unsaturated ketones belonging to

Series-B.

The δHβ chemical shifts (ppm) with Hammett constant σ+ has also shown

satisfactory correlation (r = 0.903) for all the substituents except 4-OCH3 and 4-NO2.

These two substituents namely 4-OCH3 and 4-NO2 reduce the correlations

considerably when these are included in regression.

175

The remaining Hammett constants namely σ, σI & σR and F and R parameters

have shown poor correlations (r < 0.900) for all the substituents. This is due the weak

inductive, resonance and field effects of the substituents for predicting the reactivity on

vinyl δHα proton chemical shifts (ppm) through resonance as per the conjugative

structure (46).

The correlations with Hammett constants and F and R parameters have also

shown positive ρ values. It indicates the operation of normal substituent effects on

vinyl δHα proton chemical shifts (ppm in all α,β-unsaturated ketones belonging to

series-B. Some of the single regression linear plots are shown in Figures: (64) - (69).

176

Figure - 64:

Plot of δHα(ppm) of substituted styryl 3-bromophenylphenyl ketones Vs σ

Figure – 65:

Plot of δHα(ppm) of substituted styryl 3-bromophenylphenyl ketones Vs σ+


9. 4-NO2


9. 4-NO2

177

Figure – 66: Plot of δHα(ppm) of substituted styryl 3-bromophenylphenyl ketones Vs σR

Figure – 67: Plot of δHα(ppm) of substituted styryl 3-bromophenylphenyl ketones Vs R


9. 4-NO2


9. 4-NO2

178

Figure – 68: Plot of δHβ (ppm) of substituted styryl 3-bromophenylphenyl ketones Vs σ+

Figure – 69: Plot of δHβ (ppm) of substituted styryl 3-bromophenylphenyl ketones Vs R


9. 4-NO2


9. 4-NO2

179

Since most of the single regression analyses have shown poor correlations with


regression analysis of chemical shifts of δHα and δHβ (ppm) of all α,β-unsaturated

ketones with inductive, resonance and with Swain-Lupton’s117 parameters have shown


δHα(ppm) = 7.542(± 0.143) + 0.198(±0.302) σI + 0.074(± 0.293) σR …(85)

(R = 0.925, n=9, P>90%)

δ Hα (ppm) = 7.486(±0.134) + 0.251(±0.274) F – 0.038(±0.234) R …(86)

(R = 0.935, n=9, P>90%)

δHβ(ppm) = 7.943(± 0.065) + 0.077(±0.132) σI + 0.019(± 0.129)σR …(87)

(R = 0.927, n=9, P>90%)

δHβ(ppm) = 7.957(±0.054) + 0.054(±0.124) F + 0.038(±0.102) R …(88)

(R = 0.926, n=9, P>90%)


ketones in Series-C

The 1HNMR δHα and δHβ chemical shifts (ppm) of substituted styryl

3-cyanophenyl ketones in series-C are presented in Table-13. These values are

correlated with Hammett substituent constants and F and R parameters160,161. The

results of statistical analysis158 are shown in Table-16.

18

0

Ta

ble

- 1

6

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

1H

NM

R o

f δ

Hα a

nd

δH

β (

pp

m)

of

su

bstitu

ted s

tyry

l 3

-cya

no

ph

en

yl ke

ton

es (

Se

rie

s-C

) w

ith

Ha

mm

ett c

on

sta

nts

σ, σ

+, σ

I &

σR, F

an

d R

pa

ram

ete

rs

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δHα(p

pm

) σ

0

.809

7.4

3

-0.0

4

0.1

4

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.8

13

7.4

3

-0.0

3

0.1

3

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.819

7.4

6

-0.1

2

0.1

4

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.7

85

7.4

3

0.0

3

0.1

4

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.882

7.4

5

-0.0

9

0.1

4

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.860

7.4

3

0.0

3

0.1

4

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

δHβ(p

pm

) σ

0

.800

7.8

8

-0.0

1

0.1

6

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.7

84

7.8

8

-0.0

1

0.1

6

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.822

7.8

6

-0.0

5

0.1

6

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.8

95

7.8

4

0.2

1

0.1

6

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.854

7.8

4

-0.1

2

0.1

6

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.834

7.8

17

0.2

4

0.1

5

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n;

n =

nu

mb

er

of

sub

stitu

en

ts

181

From Table-16, the δHα chemical shifts (ppm) with Hammett constants namely

σ, σ+, σI & σR and F and R parameters have shown poor correlations (r < 0.900) for all

the substituents. This is due to the incapability of polar, inductive, resonance and field

effect of the substituents to transmit their electronic effects from phenyl rings to vinyl Hα

protons chemical shifts through resonance as per the conjugative structure (47).

O

CN

H

H

O CH3

(47)

The δHβ chemical shifts with Hammett constants namely σ, σ+, σI & σR and F and

R parameters have also shown poor correlations (r < 0.900) for all the substituents.

This is due to the incapability of polar, inductive, resonance and field effect of the

substituents to transmit their electronic effects from phenyl rings to vinyl Hβ protons


The correlations of both δHα and δHβ chemical shifts (ppm) have shown negative

ρ values with Hammett constants and F and parameter except σR and R parameter. It

indicates the operation reverse substituent effects on both the δHα and δHβ chemical

shifts 9ppm) in all α,β-unsaturated ketones belonging to Series-C.

182

Since all the single regression analyses have shown poor correlations with


analysis of chemical shifts of δHα and δHβ (ppm) of all α,β-unsaturated ketones with

inductive, resonance and with Swain-Lupton’s117 parameters have shown satisfactory

correlations as shown in equations (89)-(92).

δHα(ppm) = 7.486(±0.107) – 0.123(±0.051) σI + 0.055(±0.220) σR …(89)

(R = 0.921, n=10, P> %)

δHα (ppm) = 7.479(± 0.111) – 0.103(± 0.242)F + 0.057(± 0.211) R …(90)

(R = 0.917, n=10, P> %)

δHβ(ppm) = 7.805(± 0.128) + 0.098(± 0.258) σI – 0.222(± 0.261) σR …(91)

(R = 0.962, n=10, P>95%)

δHβ(ppm) = 7.758(±0.124) + 0.177(±0.268) F – 0.269(± 0.224) R …(92)

(R = 0.948, n=10, P>90%)


ketones in Series-D

The assigned 1H NMR δHα and δHβ chemical shifts (ppm) of all the substituted

styryl 2-pyrrolyl ketones in series-D are presented in Table-13. These chemical shifts

are correlated with Hammett constants and F and R parameters160,161. The results of

statistical analysis158 with these chemical shifts (ppm) are shown in Table-17.

18

3

Ta

ble

-17

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

1H

NM

R o

f δ

Hα a

nd

δH

β (

pp

m)

of

su

bstitu

ted

sty

ryl 2

-pyrr

oly

l ke

ton

es (

Se

rie

s-D

) w

ith

Ha

mm

ett s

ub

stitu

en

t co

nsta

nts

σ,

σ+, σ

I & σ

R a

nd

F a

nd

R p

ara

mete

rs

Fre

qu

en

cy

Co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δH

α(p

pm

) σ

0

728

7.2

21

0.0

08

0.1

1

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

+

0.7

16

7.2

31

0.0

33

0.1

1

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

I 0

.827

7.1

84

0.1

33

0.1

1

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

R

0.8

25

7.2

64

0.1

11

0.1

1

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.831

7.1

83

0.1

32

0.1

1

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

R

0

.816

7.2

51

0.1

65

0.1

1

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

δH

β(p

pm

) σ

0

.821

7.8

00

-0.0

15

0.0

5

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

+

0.8

14

7.8

01

-0.0

21

0.0

4

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

I 0

.814

7.8

09

-0.0

30

0.0

4

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

σ

R

0.7

06

7.9

19

-0.0

11

0.0

5

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

F

0

.845

7.7

91

-0.0

51

0.0

5

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

R

0

.818

7.7

81

-0.0

34

0.0

4

12

H,

2-C

l, 3

-Cl, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2, 4

-NO

2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= c

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n;

n=

num

be

r of

sub

stitu

en

ts.

184

From Table-17, the δHα chemical shifts (ppm) with Hammett substituent


(r < 0.900) for all substituents. This is due to the incapability of polar, inductive,

resonance and field effect of the substituents to transmit their electronic effects from

phenyl rings to vinyl Hα protons through resonance as per the conjugative structure

(48).

NH

O

O

CH3

(48)

H

H

All the correlations of δHα chemical shifts (ppm) with Hammett substituent

constants and F and R parameters have shown positive ρ values. It indicates the

operation of normal substituent effects for δHα chemical shifts (ppm) operates in all

α,β-unsaturated ketones belonging to Series-D.

The δHβ chemical shifts (ppm) have also shown poor correlations (r < 0.900) with

Hammett constants namely σ, σ+, σI & σR and F and R parameters for all the

substituents. This is due to the incapability of polar, inductive, resonance and field effect

of the substituents to transmit their electronic effects from phenyl rings to vinyl δHβ

protons through resonance as per the conjugative structure (48).

The correlations for δHβ chemical shifts have shown negative ρ values with

Hammett constants and F and R parameters. It indicates the operation of reverse

185

substituent effects for δHβ chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to Series-D.






δHα(ppm) = 7.217(±0.076) + 0.121(±0.015) σI + 0.100(±0.013) σR ...(93)

(R = 0.935, n = 12, P > 90%)

δHα (ppm) = 7.202(±0.070) + 0.140(±0.013)F + 0.078(±0.010)R ...(94)

(R = 0.936, n = 12, P > 90%)

δHβ(ppm) = 7.807(±0.035) -0.029(±0.003) σI-0.088(±0.061) σR ...(95)

(R =0.915, n = 12, P > 90%)

δHβ(ppm) = 7.784(±0.032) + 0.012(±0.006)F +-0.033(±0.005)R ...(96)

(R = 0.919, n = 12, P> 90%)


ketones in Series-E

The 1H NMR chemical shifts (ppm) of Hα and Hβ of substituted styryl

3-methylphenyl ketones in series-E are presented in Table-13. These values are

correlated with Hammett constants and F and R parameters160,161. The results of

statistical analysis158 are shown in Table- 18.

18

6

Ta

ble

- 1

8

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

1H

NM

R o

f δ

Hα a

nd

δH

β (

pp

m)

of

su

bstitu

ted s

tyry

l 3

-meth

ylp

he

nyl ke

tone

s (

Serie

s-E

) w

ith

Ha

mm

ett c

on

sta

nts

σ,

σ+, σ

I &

σR a

nd

F a

nd

R p

ara

me

ters

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δHα(p

pm

) σ

0

.729

7.4

2

-0.1

1

0.1

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.7

32

7.4

1

-0.1

0

0.1

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.751

7.4

8

-0.2

4

0.1

0

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.7

26

7.4

0

0.1

6

0.1

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.838

7.4

6

-0.1

7

0.1

1

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.720

7.4

0

0.1

1

0.1

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

δHβ(p

pm

) σ

0

.754

7.7

5

0.2

3

0.1

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.7

46

7.7

7

0.1

7

0.1

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.728

7.7

5

0.1

5

0.1

3

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.7

67

7.8

6

0.4

2

0.1

1

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.727

7.7

6

0.1

4

0.1

3

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.758

7.8

7

0.3

4

0.1

1

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n;

n=

num

be

r of

sub

stitu

en

ts.

187

From Table-18, the δHα chemical shifts (ppm) with Hammett substituent


(r < 0.900) for all substituents. This is due to the incapability of polar, inductive,


phenyl rings to vinyl Hα protons through resonance as per the conjugative structure

(49).

O

CH3

H

H

CH2

49

H

All the correlations have shown negative ρ values with Hammett constants and

F parameter except σR and R parameter. This indicates the operation of reverse

substituent effects on δHα chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to series-E.

The δHβ chemical shifts (ppm) have also shown poor correlations (r < 0.900) with

Hammett substituent constants namely σ, σ+, σI & σR and F and R parameters for all the

substituents. This is due to the weak polar, inductive, resonance and field effect of the

substituents for predicting the reactivity on vinyl Hβ protons through resonance as per

the conjugative structure (49).

The correlations of δHβ chemical shifts (ppm) have shown positive ρ values with

Hammett constants and F and R parameters. It indicates the operation of normal

substituent effects on δHβ chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to Series-E.

188






δ Hα(ppm) = 7.518(±0.075) – 0.251(±0.158) σI +0.182 (±0.201) σR …(97)

(R = 0.959, n=9, P>90%)

δ Hα(ppm) = 7.477(±0.082) – 0.166(±0.177)F + 0.084(±0.208) R …(98)

(R = 0.941, n=9, P>90%)

δ Hβ(ppm) = 7.812(±0.085) + 0.137(±0.164)σI +0.083(±0.216)σR …(99)

(R = 0.966, n=9, P>95%)

δHβ(ppm) = 7.796(±0.083) + 0.193(±0.159) F + 0.386(±0.188) R …(100)

(R = 0.968, n=9, P>95%)

189

1.3.3.2 CORRELATION ANALYSIS OF 13C NMR SPECTRAL DATA OF

α,β-UNSATURATED KETONES

The 13C NMR spectra of a large number of different acetophenones and styrenes

were studied extensively by Dhami and Stothers162-163. They found a linear correlation of

the chemical shifts of the Carbonyl carbons with Hammett σ constants in styrene. An

attempt to correlate the CO chemical shifts with any kind of σ constants was satisfactory

and good in their system.

The general structure of all the synthesized α,β-unsaturated ketones are

shown in (44) with the incorporation of 3,4,5-trimethoxyphenyl, 3-bromophenyl,

3-cyanophenyl, 2-pyrrolyl and 3-methylphenyl groups in the place of R in (44).

The recorded 13C NMR spectra of the present investigation without substituents

in phenyl rings are shown in Figures: (70)-(74).

19

0

Fig

ure

-70

: 1

3C

NM

R s

pe

ctr

um

of

sty

ryl 3

,4,5

-trim

eth

oxyp

he

nyl ke

ton

e (

Se

rie

s-A

)

O

OC

H3

H3C

O

H3C

O

19

1

Fig

ure

-71

: 1

3C

NM

R s

pe

ctr

um

of

sty

ryl 3

-bro

mo

yp

hen

yl ke

ton

e (

Serie

s-B

)

O

Br

19

2

Fig

ure

-72

: 1

3C

NM

R s

pe

ctr

um

of

sty

ryl 3

-cya

no

yp

he

nyl ke

ton

e (

Se

rie

s-C

)

O

CN

19

3

Fig

ure

-73

: 1

3C

NM

R s

pe

ctr

um

of

sty

ryl 2

-pyrr

oly

l ke

ton

e (

Se

rie

s-D

)

O

N H

19

4

Fig

ure

-74

: 1

3C

NM

R s

pe

ctr

um

of

sty

ryl 3

-me

thylp

he

nyl ke

ton

e (

Se

rie

s-E

)

O

CH

3

195

The assignment of chemical shifts for the ethylenic carbons is based on the

following consideration. In monosubstituted styrenes, the α carbon (nearer to phenyl

ring falls in a quite well-defined region, 133-138 ppm. In substituted styryl


ketones, the carbon atom considered as Cβ whose chemical shifts fall in the region

134-146 ppm. The low field absorption is caused by the electron withdrawing aryl group

attached to neighboring carbon. The other carbon atom of ethylenic bond Cα, lies

relatively at higher field (119-129 ppm) than the corresponding carbon in styrenes.

Based on this hypothesis, it is attempted in the present investigation, to determine to

what extent 13C chemical shifts reflect the electronic influence of substituents, and also

to interpret the transmission of substituent effects on CO, Cα and Cβ carbons in

substituted styryl 3,4,5-trimethoxyphenyl, 3-bromophenyl, 3-cyanophenyl, 2-pyrrolyl

and 3-methylphenyl ketones.

The observed carbonyl carbon, Cα and Cβ chemical shifts (δppm) of all the

synthesized α,β-unsaturated ketones of series (A to E) are presented in Table-19.

196

Table-19

The 13C NMR chemical shifts (ppm) of CO, Cα and Cβ carbons in substituted styryl

3,4,5-trimethoxyphenyl (Series-A), 3-bromophenyl (Series-B),

3-cyanophenyl (Series-C), 2-pyrrolyl (Series-D) and 3-methylphenyl ketones (Series-E)

Series-A: Substituted 3,4,5-trimethoxyphenyl ketones

S. No Substituent δCO(ppm) δCα(ppm) δCβ(ppm)

1 H 188.59 123.03 143.95

2 3-Br 188.92 123.08 143.07

3 4-Br 188.3 122.16 142.57

4 2-F 188.64 124.52 149.29

5 2-OCH3 189.35 119.48 144.74

6 4-OCH3 189.44 119.57 144.78

7 2-CH3 190.25 125.76 142.76

8 4-CH3 188.77 122.98 144.13

9 4-NO2 187.70 122.86 141.32


1 H 189.10 121.43 145.78

2 2-Br 189.44 121.90 144.02

3 2-Cl 189.25 121.81 143.95

4 4-Cl 188.60 121.09 144.43

5 4-F 189.13 119.08 145.64

6 4-CH3 189.17 120.41 145.88

7 4-OCH3 190.41 120.81 141.09

8 3-NO2 189.09 122.94 140.37

9 4-NO2 196.15 123.15 138.15

Table continued...

197



1 H 188.33 120.80 146.60

2 3-Br 177.43 129.71 140.83

3 4-Br 191.13 129.45 139.86

4 2-Cl 187.98 126.42 140.42

5 3-Cl 179.98 126.35 141.31

6 2-OCH3 190.25 125.32 142.76

7 3-OCH3 179.87 120.98 142.22

8 4-OCH3 179.81 121.45 141.72

9 4-CH3 188.40 129.22 141.89

10 3-NO2 187.57 123.34 143.33


1 H 178.93 122.04 142.25

2 2-Cl 177.98 126.42 140.42

3 3-Cl 177.42 125.81 140.83

4 4-Cl 178.31 126.92 141.24

5 3-F 179.48 126.35 141.31

6 4-F 178.65 125.17 141.01

7 2-OCH3 178.82 121.45 141.72

8 3-OCH3 178.86 120.97 142.22

9 4-OCH3 179.08 119.71 142.08

10 4-CH3 178.99 125.04 142.35

11 3-NO2 177.84 122.26 139.26

12 4-NO2 177.82 122.38 140.24

Table continued...

198



1 H 190.76 125.72 145.66

2 3-Br 190.21 125.80 142.80

3 4-Br 189.71 125.61 142.81

4 3-Cl 198.43 125.82 142.90

5 4-Cl 196.82 125.81 142.92

6 4-F 190.50 122.01 138.51

7 4-CH3 198.91 125.70 144.83

8 3-NO2 197.71 124.83 141.40

9 4-NO2 197.82 123.82 134.81

1.3.3.2.1 Correlation analysis of 13C NMR spectral data of α,β-unsaturated

ketones in Series-A

The assigned chemical shifts (ppm) of CO, Cα and Cβ carbons, in substituted

styryl 3,4,5-trimethoxyphenyl ketones in series-A are presented in Table-19. These

chemical shifts are correlated with Hammett constants and F and R parameters160,161.

The results of statistical analysis158 are shown in Table-20.

19

9

Ta

ble

- 2

0

The

re

su

lts o

f sta

tistical a

na

lysis

of

13C

NM

R o

f δ

CO

, δ

Cα a

nd

δCβ ch

em

ica

l sh

ifts

(ppm

) of

sub

stitu

ted

sty

ryl 3

,4,5

-trim

eth

oxyp

he

nyl

ke

tone

s (

Se

rie

s-A

) w

ith

Ha

mm

ett

co

nsta

nts

σ,

σ+, σ

I &

σR

an

d F

and

R p

ara

mete

rs

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

O(p

pm

) σ

0

.907

18

9.1

4

-1.5

40

0.5

3

7

H,

3-B

r, 4

-Br,

2-F

, 4

-OC

H3, 2

-CH

3, 4

-NO

2

σ

+

0.9

74

18

9.1

5

-1.0

71

0.6

0

7

H,

3-B

r, 4

-Br,

2-F

, 4

-OC

H3, 2

-CH

3, 4

-NO

2

σ

I 0

.907

18

9.5

6

-2.0

91

0.5

3

8

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-NO

2

σ

R

0.8

38

18

8.7

1

-1.1

88

0.7

3

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.868

18

9.5

5

-1.8

72

0.5

7

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.832

18

8.7

2

-0.9

22

0.7

4

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

δC

α(p

pm

) σ

0

.719

12

2.3

3

1.1

50

2.1

5

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4-C

H3, 4

-NO

2

σ

+

0.9

08

12

2.3

9

0.3

91

2.1

9

6

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3,

4-N

O2

σ

I 0

.804

12

2.5

7

0.3

63

2.1

9

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.8

36

12

3.1

3

3.1

32

2.0

4

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.705

12

2.3

4

0.3

93

2.1

9

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.732

12

3.1

5

2.5

71

2.0

8

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 4

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

Tab

le c

on

tinu

ed..

..

20

0

.

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n; n

= n

um

be

r of

su

bstitu

ents

.

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

β(p

pm

) σ

0

.726

14

4.3

6

-1.7

31

2.3

4

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 3

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

+

0.7

02

14

4.1

8

-0.1

20

2.4

2

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 3

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

I 0

.704

14

4.2

8

-0.4

12

2.4

2

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 3

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

σ

R

0.6

59

14

2.8

3

-6.2

84

1.8

2

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 3

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

F

0

.721

14

3.6

1

1.7

43

2.3

7

9

H,

3-B

r, 4

-Br,

2-F

, 2

-OC

H3, 3

-OC

H3, 2

-CH

3, 4

-CH

3, 4

-NO

2

R

0

.906

14

2.5

3

-6.1

41

1.7

4

7

H,

3-B

r, 4

-Br,

2-F

, 2

-CH

3,

4-C

H3,

4-N

O2

201

From the Table-20, the carbonyl carbon chemical shifts δCO(ppm) with

Hammett substituent constants namely σ (r = 0.907), σ+ (r = 0.974) and σI (r = 0.907)

have shown satisfactory correlations. All the substituents except 2-OCH3 and

4-CH3 have shown satisfactory correlations with Hammett t constants namely σ and σ+.

The Hammett constant σI has also also shown satisfactory correlations for all

substituents except 4-CH3 substituent. These two substituents namely 2-OCH3 and

4-CH3 reduce the correlations considerably when these are included in regression.

The remaining Hammett constant σR and F and R parameters have shown poor

correlations (r < 0.900) for all the substituents. This is due to the incapability of

resonsnce andfield effects of the substituents for predicting the reactivity on δCO

chemical shifts (ppm) through resonance as per the conjucative stucture (45).

O

OCH3

H3CO

H3CO

O

CH3

(45)

All the correlations have shown negative ρ values with Hammett consatnts and

F and R parameters. This indicates the operation reverse substituent effects on δCO

chemical shifts(ppm) in all α,β-unsaturated ketones belonging to Series-A.

The chemical shifts(ppm) of δCα vinyl carbons with Hammett constant

σ+ (r = 0.908) has shown satisfactory correlation for all the substituents except

4-OCH3, 2-CH3 and 4-CH3. These three substituents namely 4-OCH3, 2-CH3 and

4-CH3 reduce the correlations considerably when these are included in regression.

202

The remaining Hammett constants namely σ, σI & σR and F and R parameters

have shown poor correlations (r < 0.900) for all the substituents. This is due to weak

inductive, resonance and field effect of the substituents to transmit their electronic

effects from phenyl rings to vinyl δCα chemical shifts (ppm) through resonance as per

the conjucative structure (45).

All the correlations with δCα chemical shifts (ppm) have shown positive

ρ values with Hammett constants and F and R parameters. It indicates the operation of

normal substituent effects on δCα chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to Series-A.

The Cβ chemical shifts (ppm) with R parameter has also shown satisfactory

correlation (r = 0.906) for all the substituents except 2-OCH3 and 3-OCH3. These two

substituents namely 2-OCH3 and 3-OCH3 reduce the correlations when these are


The Hammett constants namely σ, σ+, σI & σR and F parameter have shown

poor correlations (r < 0.900) for all the substituents. This is due to weak polar,

inductive and field effect of the substituents to transmit their electronic effects from

phenyl rings to vinyl δCα chemical shifts (ppm) through resonance as per the

conjucative structure (45).

All the correlations of δCβ chemical shifts (ppm) have shown negative ρ values

with Hammett constants and R parameter except F parameter. It indicates the

operation of reverse substituent effects in all α,β-unsaturated ketones except

belonging to Series-A. Some of the single regression linear plots are shown in

Figures:(75) - (80).

203

Figure – 75: Plot of δCO(ppm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs σ

Figure – 76:

Plot of δCO(ppm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs σ+

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

204

Figure – 77: Plot of δCO(ppm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs σI

Figure – 78:

Plot of δCα(ppm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs σ+

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

205

Figure – 79:

Plot of δCβ(ppm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs R

Figure – 80:

Plot of δCβ(ppm) of substituted styryl 3,4,5-trimethoxyphenyl ketones Vs σ+

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

1. H 2. 3-Br 3. 4-Br 4. 2-F 5. 2-OCH3 6. 4-OCH3 7. 2-CH3

8. 4-CH3 9. 4-NO2

206

Since most of the single regression linear analyses have shown poor

correlations with few Hammett constants and F and R parameters, it is decided to go

for multi regression analysis. The multi regression analysis of chemical shifts (ppm) of

CO, Cα and Cβ carbons of all α,β-unsaturated ketones with inductive, resonance and

Swain-Lupton’s117 parameters produce satisfactory correlations as shown in equations

(101)-(106).

δCO(ppm) = 189.312(±0.293) - 2.117(±0.662) σI - 6.028(±0.718) σR …(101)

(R = 0.982, n=9, P>95%)

δCO (ppm) = 189.276(±0.281) - 2.091(±0.615)F - 1.398(±0.653)R …(102)

(R = 0.983, n=9, P>95%)

δCα (ppm) = 123.233(±0.1.334) - 0.034(±0.043)σI + 3.131(±1.275)σR …(103)

(R = 0.936, n=9, P>90%)

δCα (ppm) = 122.918(±1.340) + 0.934(±0.894) F + 2.779(±1.127) R …(104)

(R = 0.934, n=9, P>90%)

δCβ(ppm) = 142.978(±1.182) - 0.421(±0.701) σI - 6.284(±2.913) σR …(105)

(R = 0.966, n=9, P>95%)

δCβ (ppm)= 142.384(±1.127) + 0.582(±0.433) F - 6.027(±2.628) R …(106)

(R = 0.970, n=9, P>95%)


ketones in Series-B

The assigned chemical shifts (ppm) of CO, Cα and Cβ carbons, in substituted

styryl 3-bromophenyl ketones in series-B are correlated with Hammett sigma constants

and F and R parameters160,161. The results of statistical analysis158 shown in

Table-21.

20

7

Ta

ble

- 2

1

The

re

su

lts o

f sta

tistical a

na

lysis

of

13C

NM

R o

f δ

CO

, δ

Cα a

nd

δCβ ch

em

ica

l sh

ifts

(ppm

) of

sub

stitu

ted

sty

ryl 3

-bro

mo

phe

nyl ke

tone

s

with

Ha

mm

ett

con

sta

nts

σ,

σ+, σ

I &

σR

an

d F

an

d R

pa

ram

ete

rs

Ch

em

ica

l sh

ifts

C

on

sta

nt

s

r I

ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

O(p

pm

) σ

0

.705

19

0.0

3

4.6

5

1.7

7

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.8

50

19

0.2

2

2.0

3

2.1

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.850

18

0.3

8

5.1

2

2.1

6

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.8

57

19

1.5

1

5.5

6

2.0

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.785

19

1.5

1

5.5

6

2.0

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.854

19

1.5

1

4.5

5

2.0

7

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

δC

α(p

pm

) σ

0

.813

12

2.1

1

0.4

1

0.9

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.7

11

12

2.0

9

-0.1

7

0.9

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.805

12

2.1

9

-0.2

3

0.9

6

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.8

04

12

2.5

3

1.5

7

0.8

7

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.809

12

2.2

3

-0.3

4

0.9

6

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.819

12

2.3

1

0.5

9

0.9

4

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

Tab

le c

on

tinu

ed..

.

20

8

r

= c

orr

ela

tio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n;

n

= n

um

be

r of

su

bstitu

en

ts.

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

β(p

pm

) σ

0

.809

14

1.6

8

-0.6

3

2.5

7

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

+

0.8

22

14

1.7

6

-0.8

7

2.5

2

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

I 0

.900

14

3.2

1

-4.7

3

2.2

9

6

4-C

l, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

σ

R

0.8

41

14

2.0

5

1.4

0

2.5

5

9

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

F

0

.905

14

3.8

0

-5.1

5

2.1

8

6

4-C

l, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2,

4-N

O2

R

0

.925

14

2.4

4

2.3

2

2.4

7

8

H,

2-B

r, 2

-Cl, 4

-Cl, 4

-F,

4-C

H3, 4

-OC

H3,

3-N

O2

209

From the Table-21, the chemical shifts (ppm) of CO carbon with Hammett

substituent constants namely σ, σ+, σI & σR and F and R parameters have shown poor


resonance and field effects of the substituents to predict their reactivity for all δCO

chemical shifts (ppm) through resonance as per the conjugative structure (46).

O

Br

H

H

O

(46)

CH3

All the correlations for δCO chemical shifts (ppm) have shown positive ρ values

with Hammett constants and F and R parameters. It indicates the operation normal

substituent effects on δCO chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to Series-B.

The δCα chemical shifts (ppm) have also shown poor correlations (r < 0.900)

with Hammett constants namely σ, σ+, σI & σR and F and R parameters for all


substituents to transmit their electronic effects from phenyl rings to vinyl Cα carbon

atoms through resonance as per the conjugative structure shown in (46).


parameter except σ & σR constants and R parameter. It indicates the operation of

reverse substituent effects in all α,β-unsaturated ketones belonging to Series-B.

.

210

However, the Cβ chemical shifts (ppm) with Hammett constant σI (r = 0.900) and

F (r = 0.905) and R (r = 0.925) parameters have shown satisfactory correlations for all

the substituents.

All the substituents except parent compound (H) of this series - B, 2-Br and

2-Cl substituentshave shown satisfactory correlation with Hammett σI constant and F

parameter. The R parameter has also shown satisfactory correlation with all the

substituents except 4-NO2 substituent. The parent compound (H) of this series - B,

2-Br, 2-Cl and 4-NO2 substituents reduce the correlations considerably when these are


The remaining Hammet constants namely σ, σ+ and σR have shown poor

correlations (r < 0.900) for all the substituents. This is due to weak polar and

resonance effects of the substituents to transmit their electronic effects from phenyl

rings to vinyl Cβ carbons through resonance as per the conjucative structure shown in

(46).

All the correlations have shown negative ρ values with Hammett constants and

F parameter except σR and R parameter. It indicates the operation of reverse

substituent effects in all α,β-unsaturated ketones belonging to Series-B. Some of the

single regression linear plots are shown in Figures: (81)-(84).

211

Figure – 81:

Plot of δCβ(ppm) of substituted styryl 3-bromophenyl ketones Vs σI

Figure – 82:

Plot of δCβ(ppm) of substituted styryl 3-bromophenyl ketones Vs F


9. 4-NO2


9. 4-NO2

212

Figure - 83:

Plot of δCβ(ppm) of substituted styryl 3-bromophenyl ketones Vs R

Figure - 84:

Plot of δCβ(ppm) of substituted styryl 3-bromophenyl ketones Vs σ+


9. 4-NO2


9. 4-NO2

213






(107)-(112).

δCO(ppm) = 189.832(± 1.153) + 5.447(±2.533) σI + 5.834(± 2.418) σR …(107)

(R = 0.978, n=9, P>95%)

δCO (ppm) = 190.106(±1.248) + 4.471(± 1.602) F + 5.087(± 2.236) R …(108)

(R = 0.973, n=9, P>95%)

δCα (ppm) = 122.584(± 0.654) – 0.156(±0.435) σI + 1.564(± 0.374) σR …(109)

(R = 0.942, n=9, P>90%)

δCα (ppm) = 122.386(±0.693) – 0.243(±0.454) F + 0.566(±0.257)R …(110)

(R = 0.926, n=9, P>90%)

δCβ (ppm) = 143.504(± 1.704) – 4.675(±1.754) σI + 1.172(± 0.584) σR …(111)

(R = 0.987, n=9, P>95%)

δCβ (ppm) = 143.972(±1.564) – 4.876(±1.258) F + 1.744(±0.793) R …(112)

(R = 0.957, n=9, P>90%)


ketones in Series-C

The assigned chemical shifts (ppm) of CO, Cα and Cβ carbons of substituted

styryl 3-cyanophenyl ketones in Series-C are presented in Table-19. These chemical

shifts (ppm) are correlated with Hammett constants and F and R parameters160,161.

The results of statistical analysis158 are shown in Table-22.

21

4

Ta

ble

- 2

2

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

13C

NM

R o

f δ

CO

, δ

Cα a

nd

δC

β (

ppm

) of

su

bstitu

ted s

tyry

l 3

-cya

no

ph

en

yl ke

ton

es (

Se

rie

s-C

) w

ith

Ha

mm

ett c

on

sta

nts

σ, σ

+, σ

I & σ

R a

nd

F a

nd

R p

ara

mete

rs

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

O(p

pm

) σ

0

.717

18

5.3

9

-2.6

9

5.3

8

10

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.8

05

18

5.1

2

-0.6

2

5.4

5

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.712

18

6.0

4

-2.9

5

5.4

2

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.7

17

18

5.9

6

4.1

7

5.3

8

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.751

18

6.4

3

-4.1

4

5.3

9

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.808

18

6.7

8

6.6

0

5.2

1

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

δC

α(p

pm

) σ

0

.813

12

5.1

0

1.6

6

3.6

9

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.7

19

12

5.1

4

1.2

3

3.6

8

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.722

12

4.1

3

3.5

6

3.6

5

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

R

0.8

42

12

5.7

8

2.2

5

3.7

1

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.812

12

4.2

6

3.1

7

3.6

8

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

R

0

.817

12

5.9

6

2.5

3

3.6

9

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

T

ab

le c

on

tinu

ed..

......

.

21

5

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

β(p

pm

) σ

0

.714

14

2.1

9

-0.8

0

1.9

9

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

+

0.7

54

14

2.1

8

-0.6

7

1.9

8

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

σ

I 0

.909

14

3.4

8

-4.2

3

1.7

6

8

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3

σ

R

0.8

26

14

2.5

9

-2.3

6

1.9

4

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

F

0

.916

14

3.6

1

-4.6

3

1.7

6

8

H,

3-B

r, 4

-Br,

2-C

l, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3

R

0

.824

14

2.7

4

-2.5

1

1.9

1

10

H

, 3

-Br,

4-B

r, 2

-Cl, 3

-Cl, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n; n

= n

um

be

r of

sub

stitu

en

ts

216

From the Table-22, chemical shifts (ppm) of CO carbon with Hammett

constants namely σ, σ+, σI & σR and F and R parameters have shown poor


resonance and field effects of the substituents for predicting the reactivity on all the

δCO chemical shifts (ppm) through resonance as per the conjugative structure (47).

O

CN

H

H

O CH3

(47)

All the correlations for δCO chemical shifts (ppm) with Hammett constants and

F parameter have shown negative ρ values except σR constant and R parameter. This

indicates the operation of reverse substituent effects for δCO chemical shifts (ppm) in

all α,β-unsaturated ketones belonging to Series-C.

The observed chemical shifts (ppm) of vinyl Cα carbons have also shown poor

correlations (r < 0.900) with Hammett substituent constants namely σ, σ+, σI & σR and

F and R parameters. This is due to the incapability of polar, inductive, resonance and

field effect of the substituents to transmit their electronic effects from phenyl rings to

vinyl δCα chemical shifts (ppm) through resonance as per the conjugative structure

shown in (47).

All the correlations of δCα chemical shifts (ppm) with Hammett constants and F

and R parametrs have shown positive ρ values. This indicates the operation of normal

substituent effects on δCα chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to Series-C.

217

However, the chemical shifts (ppm) of the Cβ carbons with Hammett constant

σI (r = 0.909) and F (r = 0.916) parameter have shown satisfactory correlations for all

the substituents except 4-CH3 and 3-NO2. These two substituents namely 4-CH3 and

3-NO2 are reduce the correlations considerably when these are included in regression.

The remaining Hammet constants namely σ, σ+ and σR and R parameter have

shown poor correlations (r < 0.900) for all the substituents. This is due to weak polar

and resonance effects of the substituents to transmit their electronic effects from

phenyl rings to vinyl δCβ chemical shifts(ppm) through resonance as per the

conjucative structure (47).

The correlations of δCβ chemical shifts(ppm) with Hammett constants and F and

R parameters have shown negative ρ values. It indicates the operation of reverse

substituent effects on δCβ chemical shifts(ppm) in all α,β-unsaturated ketones belonging

to Series-C. Some of the single regression linear plots are shown in Figures:(85)-(86).

218

Figure - 85:

Plot of δCβ(ppm) of substituted styryl 3-cyanophenyl ketones Vs σI

Figure - 86:

Plot of δCβ (ppm) of substituted styryl 3-cyanophenyl ketones Vs F


8. 4-OCH3 9. 4-CH3

10. 3-NO2


8. 4-OCH3 9. 4-CH3

10. 3-NO2

219






(113)-(118).

δCO(ppm) = 187.303(± 4.062) – 3.704(± 1.688)σI + 4.775(± 1.814)σR …(113)

(R = 0.923, n=10, P>90%)

δCO (ppm) = 188.784(± 4.219) – 5.525(±1.113)F + 7.347(± 2.731)R …(114)

(R = 0.937, n=10, P>90%)

δCα (ppm) = 124.567(± 2.783) + 3.292(± 1.939) σI + 1.714(± 0.023) σR …(115)

(R = 0.924, n=10, P>90%)

δCα (ppm) = 124.961(± 3.023) + 2.772(± 0.547) F + 2.164(± 0.555) R …(116)

(R = 0.923, n=10, P>90%)

δCβ(ppm) = 144.308(± 1.235) – 4.722(±1.637) σI + 3.124(± 1.669) σR …(117)

(R = 0.926, n=10, P>90%)

δCβ (ppm) = 144.642(±1.307) – 5.243(±1.817) F + 3.212(±1.344) R …(118)

(R = 0.946, n=10, P>90%)


ketones in Series-D

The assigned chemical shifts (ppm) of CO, Cα and Cβ carbons carbons of

substituted styryl 2-pyrrolyl ketones in series-D are presented in Table-19. These

chemical shifts are correlated with Hammett constants and F and R parameters. The

statistical analysis158 of substituent effects on the CO, Cα and Cβ carbons with various

Hammett substituent constants and F & R parameters160,161 are presented in Table-23.

22

0

Ta

ble

- 2

3

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

13C

NM

R o

f δ

CO

, δ

Cα a

nd

δC

β (

ppm

) of

su

bstitu

ted s

tyry

l 2

-pyrr

oly

l ke

ton

es (

Se

rie

s-D

) w

ith

Ha

mm

ett c

on

sta

nts

σ, σ

+, σ

I &

σR

and

F a

nd R

pa

ram

ete

rs

Ch

em

ica

l

sh

ifts

co

nsta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

O(p

pm

) σ

0

.963

17

8.6

9

-1.0

90

0.5

1

10

H,

2-C

l, 4

-Cl, 4

-F,

2-O

CH

3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

+

0.7

93

17

8.6

2

-0.7

77

0.5

3

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

I 0

.753

17

9.0

6

-1.4

51

0.5

5

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

R

0.7

51

17

8.1

8

-1.4

23

0.5

4

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

F

0

.823

17

8.7

6

-0.6

16

0.6

3

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

R

0

.862

17

8.1

1

-1.3

90

0.5

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

δC

α(p

pm

) σ

0

.836

12

3.4

4

1.6

24

2.5

0

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

+

0.7

27

12

3.5

1

1.4

02

2.5

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

I 0

.826

12

2.6

1

2.9

81

2.5

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

R

0.8

54

12

3.7

0

0.0

51

2.6

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

F

0

.829

12

2.5

2

2.8

17

2.4

9

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

R

0

.729

12

3.8

2

0.3

92

2.6

0

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

Tab

le c

on

tinu

ed..

.

22

1

Ch

em

ica

l

sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

β(p

pm

) σ

0

.981

14

1.5

2

-2.1

05

0.5

9

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

+

0.9

06

14

1.4

3

-1.5

35

0.7

2

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

I 0

.985

14

2.5

8

-3.5

61

0.5

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

σ

R

0.7

41

14

0.8

1

-1.8

15

0.8

7

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

F

0

.992

14

2.1

7

-1.2

70

0.7

5

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

R

0

.832

14

4.1

8

-2.1

70

0.8

1

12

H,

2-C

l, 3

–C

l, 4

-Cl, 3

-F,

4-F

, 2

-OC

H3,

3-O

CH

3,

4-O

CH

3,

4-C

H3,

3-N

O2,

4-N

O2

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n; n

= n

um

be

r of

sub

stitu

en

ts.

222

From Table-23, the δCO chemical shifts (ppm) with Hammett constant σ has

shown satisfactory correlation (r = 0.963) for all the substituents except 3-Cl and 3-F

substituents. These two substituents namely 3-Cl and 3-F reduce the correlations

considerably when these are included in regression.

The remaining Hammett constants namely σ+, σI & σR and F and R parameters

have shown poor correlations (r < 0.900) for all the substituents. This is due to weak

polar, inductive, resonance and field effects of the substituents for predicting the

reactivity on δCO chemical shifts through resonance as per the conjucative stucture

(48).

NH

O

O

CH3

(48)

H

H

All the correlations of δCO chemical shifts (ppm) have shown negative ρ values


substituent effects on δCO chemical shifts (ppm) in all the α,β-unsaturated ketones


From Table-23, the δCα chemical shifts (ppm) with Hammett constants namely

σ, σ+, σI & σR and F and R parameters have shown poor correlations (r < 0.900) for all

substituents. This is due to the incapability of polar, inductive, resonance and field

effects of the substituents to transmit their electronic effects from phenyl rings to vinyl

Cα carbons through resonance as per the conjucative stucture shown in (48).

223

All the correlations for δCα chemical shifts (ppm) have shown positive ρ values


substituent effects on δCα chemical shifts (ppm) in all α,β-unsaturated ketones


The δCβ chemical shifts (ppm) with Hammett constants namely

σ (r = 0.981), σ+ (r = 0.906) and σI (r = 0.985) and F (r = 0.986) parameter have shown

satisfactory correlations for all the substituents except 3-NO2 and 4-NO2 substituents.

These two substituents namely 3-NO2 and 4-NO2 reduce the correlations considerably

when these are included in regression analysis.


correlations (r < 0.900) for all the substituents. This is due to the incapability of the

resonance effect of the substituents to transmit their electronic effects from phenyl rings

to vinyl Cβ carbons through resonance as per the conjucative structure shown in (48) in

all α,β-unsaturated ketones.

All the correlations for δCβ chemical shifts (ppm) have shown negative ρ values

with Hammett constants and F and R parameters. It indicates the operation of reverse

substituent effects on δCβ chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to Series-D. Some of the single regression linear plots are shown in

Figures: (87)-(92).

224

Figure – 87: Plot of δCO(ppm) of substituted styryl 2-pyrrolyl ketones Vs σ

Figure – 88: Plot of δCβ(ppm) of substituted styryl 2-pyrrolyl ketones Vs σ

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

225

Figure – 89:

Plot of δCβ (ppm) of substituted styryl 2-pyrrolyl ketones Vs σ+

Figure – 90: Plot of δCβ (ppm) of substituted styryl 2-pyrrolyl ketones Vs σI

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

226

Figure – 91:

Plot of δCβ (ppm) of substituted styryl 2-pyrrolyl ketones Vs F

Figure – 92: Plot of δCβ (ppm) of substituted styryl 2-pyrrolyl ketones Vs σR

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

1. H 2. 2-Cl 3. 3-Cl 4. 4-Cl 5. 3-F 6. 4-F 7. 2-OCH

3

8. 3-OCH3

9. 4-OCH3

10.4-CH3

11.3-NO2

12.4-NO2

227






(119)-(124).

δCO(ppm) = 1178.70 (±0.314) –1.292(±0.062) σI –1.289(±0.05) σR ...(119)

(R =0.973, n = 12, P > 95%)

δCO (ppm) = 178.41(±0.034) -0.774(±0.057)F –1.466(±0.052)R ...(120)

(R =0.970, n = 12, P> 95%)

δCα (ppm) =122.58 (±1.769) +2.939(±0.350) σI – 0.306(±0.002) σR ...(121)

(R = 0.926, n = 12, P > 90%)

δCα (ppm) =122.67(±1.619) + 2.943(±0.237)F + 0.655(±0.287) R ...(122)

(R =0.930, n = 12, P> 90%)

δCβ(ppm) =142.17(±0.233) - 3.380(±0.047) σI + 1.463(±0.043) σR ...(123)

(R =0.994, n = 12, P > 95%)

δCβ (ppm)=141.85(±0.265) - 2.819(±0.517)F – 1.947(±0.548)R ...(124)

(R =0.973, n = 12, P > 95%)


ketones in Series-E

The assigned CO, Cα and Cβ carbon chemical shifts (ppm) of substituted styryl

3-methylphenyl ketones in series-E are presented in Table-19. These chemical shifts

are correlated with Hammett constants and F and R parameters160,161. The results of

statistical analysis158 are shown in Table-24.

22

8

Ta

ble

- 2

4

The

re

su

lts o

f sta

tistical a

na

lysis

of

ch

em

ica

l sh

ifts

of

13C

NM

R δ

CO

, δ

Cα a

nd

δC

β (

pp

m)

of

su

bstitu

ted s

tyry

l 3

-meth

ylp

he

nyl ke

tone

s (

Serie

s-E

) w

ith

Ha

mm

ett c

on

sta

nts

σ,

σ+, σ

I, σ

R, F

an

d R

pa

ram

ete

rs

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

O(p

pm

) σ

0

.828

19

3.4

5

3.7

4

4.1

7

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.8

14

19

4.0

7

1.6

7

4.3

0

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.804

19

4.2

5

0.6

6

4.3

4

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.8

42

19

5.4

7

9.0

6

3.9

2

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.803

19

4.7

5

0.5

6

4.3

4

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.845

19

5.7

7

8.3

9

3.8

6

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

δC

α(p

pm

) σ

0

.811

12

5.1

3

-0.4

8

1.3

9

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

+

0.8

00

12

4.9

9

-0.0

1

1.4

0

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

I 0

.843

12

5.9

0

-2.2

4

1.2

6

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

σ

R

0.8

34

12

5.2

4

-2.3

1

1.3

1

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.865

12

6.3

7

-3.2

7

1.0

5

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

R

0

.839

12

5.3

4

2.3

1

1.2

8

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

T

ab

le c

on

tinu

ed..

.

22

9

r =

co

rre

latio

n c

oeff

icie

nt;

ρ

= s

lop

e;

I =

in

terc

ep

t; s

= s

tand

ard

de

via

tio

n;

n =

nu

mb

er

of

sub

stitu

en

ts.

Ch

em

ica

l sh

ifts

C

on

sta

nts

r

I ρ

s

n

Co

rre

late

d d

eriva

tive

s

δC

β(p

pm

) σ

0

.959

14

3.4

6

-6.0

8

2.7

4

7

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-C

H3,

3-N

O2

σ

+

0.9

49

14

2.9

0

-4.4

0

2.9

5

7

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-C

H3,

3-N

O2

σ

I 0

.969

14

5.2

6

-8.6

9

2.4

4

7

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-C

H3,

3-N

O2

σ

R

0.8

12

14

1.5

1

-2.0

2

3.3

7

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

F

0

.976

14

5.6

0

-9.1

9

2.2

0

8

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2

R

0

.808

14

1.5

5

-1.1

5

3.3

8

9

H,

3-B

r, 4

-Br,

3-C

l, 4

-Cl,

4-F

, 4

-CH

3,

3-N

O2, 4

-NO

2

230

From the Table-24, the chemical shifts (ppm) of CO carbon with Hammett


(r < 0.900) for all the substituents. This is due to weak polar, inductive, resonance and

field effects of the substituents for predicting the reactivity on δCO chemical shifts

(ppm) through resonance as per the conjucative stucture (49).

O

CH3

H

H

CH2

H(49)

All the correlations for δCO chemical shifts (ppm) have shown positive ρ values


substituent effects on δCO chemical shifts (ppm) in all α,β-unsaturated ketones

belonging to Series-E.

From the Table-24, the δCα chemical shifts (ppm) with Hammett constants

namely σ, σ+, σI & σR and F and R parameters have also shown poor correlations

(r < 0.900) for all the substituents. This is due to incapability of polar, inductive,


phenyl rings to vinyl Cα carbons through resonance as per the conjucative stucture

shown in (49).

All the correlations for δCα chemical shifts (ppm) have shown negative ρ values

with Hammett constants and F parameter except R parameter. It indicates the

operation of reverse substituent effects on vinyl δCα chemical shifts (ppm) in all

α,β-unsaturated ketones belonging to Series-E.

231

However the δCβ chemical shifts (ppm) with Hammett constants namely

σ (r = 0.959), σ+ (r = 0.949)and σI (r = 0.969) and F parameter (r = 0.976) have shown

satisfactory correlations for all the substituents except 4-F and 4-NO2 substituents.

These two substituents namely 4-F and 4-NO2 reduce the correlations considerably

when these are included in regression.


correlations (r < 0.900) for all the substituents. This is due to the incapability of

resonance effect of the substituents to transmit their electronic effects from phenyl

rings to vinyl Cβ carbons through resonance as per the conjucative stucture shown in

(49).

All the δCβ chemical shifts (ppm) have shown negative ρ values with Hammett

constants and F and R parameters. It indicates the operation of reverse substituent

effects on δCβ chemical shifts (ppm) in all α,β-unsaturated ketones belonging to

Series-E. Some of the single regression linear plots are shown in Figures:(93)-(96).

232

Figure – 93:

Plot of δCβ(ppm) of substituted styryl 3-methylphenyl ketones Vs σ

Figure – 94:

Plot of δCβ(ppm) of substituted styryl 3-methylphenyl ketones Vs σ+



233

Figure – 95: Plot of δCβ(ppm) of substituted styryl 3-methylphenyl ketones Vs σI

Figure – 96: Plot of δCβ(ppm) of substituted styryl 3-methylphenyl ketones Vs F



234


correlations with few Hammett constants and F and R parameters, it is decided to go for

multi regression analysis. The multi regression analysis of chemical shifts (ppm) of CO,

Cα and Cβ carbons of all α,β-unsaturated ketones with inductive, resonance and


(125)-(130).

δCO(ppm) = 195.353(±2.954) + 0.324(±0.926) σI + 9.040(±3.795) σR …(125)

(R = 0.942, n=9, P>90%)

δCO (ppm) = 195.576(±2.815) + 0.511(±0.672) F + 8.483(±3.711) R …(126)

(R = 0.945, n=9, P>90%)

δCα (ppm) =126.215(±0.867) – 2.343(±0.744) σI +2.470(±0.296) σR …(127)

(R = 0.956, n=9, P>90%)

δCα (ppm) =126.552(±0.711) – 3.053(±1.427) F + 1.776(±0.684) R …(128)

(R = 0.972, n=9, P>95%)

δCβ(ppm) =145.097(±1.825) – 8.633(±2.665) σI – 1.452(±0.827) σR …(129)

(R = 0.969, n=9, P>95%)

δCβ (ppm) =145.336(±1.534) – 9.563(±3.086) F – 2.856(±0.648) R …(130)

(R = 0.978, n=9, P>95%)

235

1.4 SCOPE OF THE PRESENT INVESTIGATION

The α,β-unsaturated ketone derivatives have been introduced as a side chain

unit in the backbone of polyimide for photo-alignment layers65. The rate of

photo-reaction was followed by the disappearance of the C=C and C=O bond in the

α,β-unsaturated ketone moiety using UV–visible spectroscopy. Three 2′-hydroxy

chalcone derivatives were electrochemically reduced to the radical anion by a reversible

one-electron transfer followed by a chemical dimerization reaction67. Several α,β-

unsaturated ketones have been evaluated as non azo dyes for dyeing of silk fabric

using metallic and natural mordants and their combination68. The titration of α,β-

unsaturated ketones with tetrabutylammonium hydroxide (TBAH) in four non-aqueous

solvents namely isopropyl alcohol, tert-butyl alcohol, N,N - dimethylformamide and

acetonitrile using potentiometric method gives the half neutralization potential values

and the corresponding pKa values69 of α,β-unsaturated ketones.

Several disubstituted ferrocenyl chalcones possess good electrochemical

sensors 70 property. Pyridine and hydroxyl chalcones undergoes [2+2]π electron

photodimerization reactions71. The intramolecular charge transfer (ICT) of an efficient

π-conjugated potential push–pull NLO chromophore,1-(4-methoxyphenyl)-3-(3,4-

dimethoxyphenyl)-2-propen-1-one to a strong electron acceptor group through the

π -conjugated bridge has been carried out from the vibrational spectra77. Furthermore, a

linear relationship between the half-wave reduction potentials of α,β-unsaturated

carbonyl compounds and the Hammett σp values were studied80. The kinetics of

oxidation study164 of substituted styryl 4-biphenyl ketones and of substituted styryl

2-fluorenyl ketones by pyridinium chlorochromate (PCC) in 90% acetic acid and 10%

water (v/v) containing perchloric acid and NaClO4 at 100, 200, 300 and 40 oC shows

that the reactions are first order in styryl ketones and PCC.

236

The self-condensation of aralkyl ketones mediated by tetrachlorosilane-ethanol

under mild conditions leads to the highly efficient and stereo defined synthesis of

β-methyl chalcones165. Indium (III) chloride in methanol efficiently catalyzes Michael

addition of aromatic and aliphatic thiols to chalcones and related compounds. This

reaction is remarkably solvent selective and it does not proceed in conventional

solvents such as tetrahydrofuran, methylene chloride and water. The Michael addition of

thiols to electron deficient alkenes is a very useful process for making carbon-sulfur

bond166.

Michael addition reactions of chalcones and aza chalcones with ethyl

acetoacetate have been successfully performed in the presence of catalytic amount of

K2CO3 and under the high speed vibration milling conditions 167. The Michael addition of

α,β-unsaturated ketone with active methylene compounds such as diethyl malonate,

nitromethane and ethyl acetoacetate catalyzed by potassium hydroxide in anhydrous

ethanol resulted in Michael adducts168 in 75-98 % yield under ultrasound irradiation in

25-90 minutes.

The mechanism of Michael addition of ethyl acetoacetate to chalcone catalyzed

by activated Ba(OH)2 leads to the C-C formation169 under mild conditions. The reaction

wes catalyzed by bases such as alkoxides, amines and more recently by other catalysts

such as KF/crown ethers and nickel bis-acetylacetonate. Single crystal XRD is a non-

destructive analytical technique which provides detailed information about the internal

lattice of crystalline substances, including unit cell dimensions, bond lengths, bond

angles and site ordering of α,β-unsaturated ketones170-173.

There is a possibility to undertake above such studies like dyeing to silk fabrics,

determination of electrochemical potentials, electrochemical sensors, etc., with the

compounds synthesized in the present investigation in future.

237

1.5 CONLUSION

Several ortho, meta- and para- substituted styryl 3,4,5-trimethoxyphenyl, styryl

3-bromophenyl, styryl 3-cyanophenyl, styryl 2-pyrrolyl and styryl 3-methylphenyl

ketones have been prepared. Their UV, IR, 1H and 13C Nuclear Magnetic Resonance

spectra have been recorded. All the observed spectral data have been correlated with

Hammett substituent constants such as σ, σ+, σI & σR and F and R parameters to seek

structure-parameter study.

Most of the carbonyl (CO) absorption maximum λmax(nm) values of

α,β-unsaturated ketones have shown satisfactory correlations with Hammett constants

namely σ and σ+. In addition, all the substituted styryl 3-bromophenyl ketones have

shown satisfactory correlations for F parameter. However, the 2-pyrrolyl

α,β-unsaturated ketones have shown poor correlations with Hammett constants and F

and R parameters.

All the synthesized α,β-unsaturated ketones have existed as equilibrium

mixtures of s-cis and s-trans conformers. In most cases, the Hammett constant σ has

shown satisfactory correlation with COs-cis frequencies (cm-1) of all the series (A to E) of

α,β-unsaturated ketones. The COs-cis frequencies (cm-1) have also shown satisfactory

correlations with most of the Hammett constants viz., σ, σ+ & σI and F parameter in

Series-A. All the Hammett constants and F and R parameters have shown poor

correlations in Series-E.

In case of carbonyl s-trans frequencies, some of the α,β-unsaturated ketones

in Series C & E have shown satisfactory correlations with few Hammett constants and R

parameter. All the Hammett constants and F and R parameters have shown poor

correlations with COs-trans frequencies in all α,β-unsaturated ketones belonging to Series

238

A, B & D. The νCHip frequencies (cm-1) have also shown poor correlations with

Hammett constants and F and R parameters except σR constant in all α,β-unsaturated

ketones.

The Hammett constants namely σ & σ+ and R parameter have also shown

satisfactory correlations with few νCHop frequencies (cm-1) in all α,β-unsaturated

ketones. Although the νCH=CHop deformation modes have also shown satisfactory

correlations with few Hammett constants and F and R parameters. All the νC=Cop

deformation modes have also shown satisfactory correlations with Hammett constant σR

in all α,β-unsaturated ketones belonging to Series-D. The νCHop and νC=Cop

deformation modes in most cases have shown poor correlations compared to other

modes of frequencies.

The 1H NMR spectral chemical shifts (ppm) of Hα protons have shown

satisfactory correlations with Hammett constants viz., σ, σ+ & σR and R parameter for all

the substituents in all the 3,4,5-trimethoxy phenyl (Series-A) and 3-bromophenyl

(Series-B) α,β-unsaturated ketones. All the Hammett constants and F and R parameters

have shown poor correlations with both the δHα and δHβ chemical shifts (ppm) have

shown poor correlations in all the 3-cyanophenyl (Series-C), 2-pyrrolyl (Series-D) and

3-methylphenyl (Series-E) α,β-unsaturated ketones.

In 13C NMR spectra, most of the chemicals shifts (ppm) of carbonyl carbons, Cα

and Cβ carbons have also shown satisfactory correlations with few Hammett constants

and F and R parameters.

In each case, the poor correlation is due to the incapability of various effects

such as inductive, polar, resonance and field effect etc., of the substituents to predict

239

the reactivity on the spectral data through resonance as per the corresponding

conjugative structures.

However in all cases, the multi linear regression analyses have shown

satisfactory correlations with Hammett constants viz., σI & σR and F and R parameters.

Furthermore, most of the correlations have shown positive ρ values for UV,

IR, 1H NMR and 13C NMR spectral data in all α,β-unsaturated ketones. This indicates

the operation of normal substituent effects in all α,β-unsaturated ketones.

Documents

CHAPTER I SYNTHESIS AND ASSESSMENT OF ...shodhganga.inflibnet.ac.in/bitstream/10603/38350/7/07...Narender and Reddy 4 0 developed a new methodology by using BF 3- Et2O to synthesize