1

CHAPTER - 1 INTRODUCTION

1.1: Introduction

Analytical chemistry involving metal complexes is based mainly on the

synthesis of selective and sensitive reagents. In this context, organic reagents occupy

a special place in the field of complexation of metal ions. These reagents, due to their

chelating nature and complexing ability are capable of forming stable, highly

coloured, insoluble and soluble complex compounds with metal ions. These metal

complexes find wide use in analytical chemistry in general and in spectrophotometric

analysis in particular.

Organic analytical reagents are the carbon compounds capable of reacting

quantitatively with metal ions or the inorganic anions, resulting in the formation of a

precipitate, an insoluble complex or a stable colour. Based on this type of reactivity,

the reagents are broadly classified as gravimetric or colorimetric reagents. In either

case, it is observed that the chelating properties of the organic compounds play a

significant role. However, a good number of methods based on the formation of

coloured products (soluble or insoluble) through redox-reactions rather than the

complex formation reactions have been reported. But the complex forming methods

still occupy predominant place in chemical analysis. The complex forming reagents

are required to possess the functional groups capable of coordinating with the metal

ion concerned to form stable and coloured metal complexes.

Even though one can not predict easily which organic compound is suitable

for the analysis of a particular metal ion, some guidelines could be worked out on the

basis of available data in the literature. It is observed that an organic compound is

required to possess acidic or basic groups besides the group containing coordinating

atoms to function as organic reagents. Some of the acidic or basic groups are listed in

Table 1.1

2

Table 1.1: Some acidic or basic groups

Carboxyl C OH

O

Sulfonic S

O

O

OH

Sulfinic S

O

OH

HS

O

OH

Arsonic As

OH

O

OH

Oximic N H

O

N OH

Nitro (primary) CH2 NO2 CH N O

OH

Nitro (secondary) RCH NO

2 RC N OH

O

Enolic C CH2 C

O OHC CH C

Phenolic (alcoholic) C OH

Thiophenolic C SH

Thioenolic N C SHorC C SH

Sulfonamidic S NH2

O

O

S OH

O

NH

Acid-imide CO NH CH2

Basic groups that

are derivatives of

ammonia

–NH2, –NHR, –NR1R

2 and cyclic allyl bound nitrogen atoms

3

The atomic groups involved in the coordination shall contain oxygen, nitrogen

or sulphur as coordinating atoms. Presence of other atoms or groups in the compound

beside these two groups exerts a fundamental effect on the usefulness or otherwise of

the organic compound as an analytical reagent. Organic compounds are easily

convertible into compounds of desired structural features through condensation or

substitution reactions. It is found that compounds containing -OH, -SH and -NO serve

as good organic reagents. Some typical compounds reported in the literature are

presented in Table 1.2 as examples.

A careful analysis of the different reports made in the literature on the use of

organic compounds as inorganic analytical reagents suggest that, certain groups are

specific for specific metals or groups of metals. These are presented in Table 1.3.

The facts mentioned above indicates that the presence of a coordinating group

(>C=N-) together with the acidic groupings (-OH, -SH) seems to favor the reactivity

of the compounds with metals such as Copper, Chromium, Cadmium, Mercury and

Lead etc. Among the compounds possessing these characteristics, hydrazones or

azomethines characterized by the presence of atomic group (>C=N-N<) seems to

offer advantageous over others. A large number of such hydrazones find application

as specrophotometric analytical reagents. Since Schiff bases also possess similar

atomic groupings as present in the hydrazones, a brief account of Schiff bases

presented in 1.1.2.

4

Table 1.2: Compounds containing -NO, -OH, -SH groups

Reagent Complex

1-Nitroso 2 naphthol –

3,6-disodium sulfonate

NaO3S

NO

OH

SO3Na

NaO3S

N

O

SO3Na

O Co/3

o- Nitrosophenol

NO

OH

N

O

O

M

Ammmonium salt of

nitrosophenylhydroxylamine

N OH(NH4)

NO

N

Fe/3

ON

NO

4-chloro-1,2-dimercaptobenzene

Cl

SH

SH

Cl

S

SM(II)

Thionalid

NH C CH2 SH

O

NH C CH2

O S

M

Thioglycolic anilide

C6H5 NH C CH2

O SH

C6H5 N C

H

O

C SCo/3

H2

4-Hydroxybenzothiazole

S

CHN

OH

S

CHN

O M

(M = ½ Cu, Ni, Zn etc)

5

Reagent Complex

Pyrogallol

OH

OH

OH

Bismuth pyrogallate

O

OBi

O

Mercaptobenzothiazole

S

CN

SH

S

CN

S M S

S

CN

Methoxy salicylaldoxime

CH NOCH3

OH

N

Cu/2O

OCH3

CH

(Copper complexes)

Dihydroxyanthraquinone

O

O

OH

OH

O

O

O

OH

M

(M=1/3, Al, Fe, Cr)

Rhodizonic acid

OH

OH

O

O

O

O

Sodium rhodizonate

O

O

O

O

O

O

Na

Na

6

Reagent Complex

9-Methyl-2,3,7-trihydroxy-6-

fluorone

O

CH3

OH

OH

HO

O

O

CH3

O

O

HO

OSbOH

Oxine

N

OH O

N

H

N

O M O

N

M

(M = one equivalent of metal)

(7-Iodo-8-hydroxyquinoline-sulfonic

acid)

NI

S

OH

HO3

HO3

N

S

O Fe/3

blue coloured ferric complex

Salicylaldoxime

CH NOH

OH

CH

OH

O

Cu/2

NN

Cu/2O

OHCH

(copper complexes)

Oxime-hydrazones

NHCH3

CH3 NHNH

OH

O

X

NH CH3

CH3N

OH

NH O

NHCH3

CH3 N

OH

NHO

M

2+

M = Sn

7

Table 1.3: Groups of specific formulas

Metal (or) Groups of metals Specific groups

Germanium [ =C(OH)-CO-]

Thallium [ -CO-CH2-CO- ]

Zirconium [ -CHOH-COOH ]

Copper C C

OH N OH

Nickel and Palladium C C

NOH NOH

Vanadium, Molybdenum and Uranium C

OH

CH

NOH

Aluminium, Ruthenium and

molybdenum

HC N

R HN CO-R'

1.1.2: Schiff bases

Schiff bases, the derivatives of carbonyl compounds formed in the reaction

with amino compounds constitute an important class of organic analytical reagents.

Since the discovery of the first Schiff base salicylidene aniline and its methyl

derivative1, many such reagents have been synthesised

2-6. These bases are

characterized by the presence of >C=N- group capable of coordinating with the metal

ion. Many poly-dentate ligands having de-localized orbitals gained importance

because of their use as model compounds for biological systems6. Schiff bases

yielding bi-nuclear and bridged complexes occupy a special place in the

spectrophotometric determination of metal ions7, 8

.

8

The compounds containing the azomethine group (>C=N-) possess basic

properties by virtue of the presence of lone pair of the electrons on the nitrogen atom

and of the general electron donating character of the double bond. They accept a

proton from a Bronsted-Lowry acid to form the conjugate cation. They react with

hydroxylic compounds to yield hydrogen bonded complexes in aprotic solvents. The

most characteristic feature relating to this basic character of the compounds lies in the

formation of complexes with metals. However, the basic strength of the >C=N- group

is insufficient by itself to permit the formation of stable complexes by simple

coordination of the lone pair to metal ions. Therefore it is essential that, another

functional group with a replaceable hydrogen atom, preferably a hydroxyl group shall

be present in the molecule of the Schiff base near enough to >C=N- group to permit

the formation of five membered or six membered ring by chelation with the metal ion.

Some of them have been listed by Holm, Everett, Chakravarthy and Sacconi9, 10

. The

coordination complexes formed with divalent metal ions vary in the structure, their

properties depending on the nature of the divalent metal ion and also on the nature of

the substituent on the nitrogen atom, the substituent if any on the aromatic ring.

Besides the utility of azomethines as complex formers in the analytical field,

they are used widely in agriculture and medicine as fungicides and drugs respectively.

Among the azomethines, hydrazones and semicarbazones are found useful as

anti-convulsants11

. The semicarbazones are also found to possess anti-tuberculosis,

anti leprosy, anti-rheumatism activities. These activities are related to their complex

forming abilities with the metal ions12-15

. In the view of the great complex forming

abilities of the azomethines and their metal complexes being used as drugs,

the author has synthesized 2,4-Dimethoxybenzaldehyde-4-hydroxybenzoylhydrazone

(DMBHBH) and 2,4-Dimethoxybenzaldehyde isonicotinoylhydrazone (DMBIH) and

also studied their spectrophotometric behavior under different pH conditions.

9

Analytical applications of hydrazones

Singh et al16

. reviewed critically the applications of hydrazones as analytical

reagents. However as the author is interested in the use of isonicotinoyl hydrazone

derived from carbonyl compounds, a brief review of the past work reported on the

isonicotinoyl hydrazone derived from carbonyl compounds is presented.

In 1975 Kouimtzis et al17

published a paper describing the extraction

spectrophotometric determination of gallium and indium at pH 6-6.5. Belal and

Chaaban18

determined Fe (II) and Fe (III) colorimetrically in the presence of each

other and other metal ions and applied to various pharmaceuticals by using

2-hydroxy-1- naphthaldehyde isonicotinoyl hydrazone, Mo(VI) in steels19

is also

determined. The complexes formed by vanadium (V) in acidic 50% aqueous ethanol

medium with acetone isonicotinoyl hydrazone and with 4-hydroxy benzaldehyde

isonicotinoyl hydrazone have been examined20

and used for the spectrophotometric

determination of vanadium. The 2-hydroxy isomer has been used for the

determination of Al (III) 21

and Zn (II), Co (II), Ni (II) and Mn (II) 22

. Napthyl methyl

ketone isonicotonic acid hydrazone23

is employed for the spectrophotometric

determination of Ti (IV). Uno and Taniguchi24

studied the fluorescent activity of

isonicotinoic acid hydrazones of a number of carbonyl compounds (2-hydroxy-1-

napthaldehyde, salicyladehyde, 2-hydroxy-m-tolualdehyde, 3-hydroxy-p-toluadehyde,

4-hydroxy-m-toluadehyde, 3-chloro-2-hydroxy benzaldehyde, 5- chloro-2-hydroxy

benzaldehyde and 2-hydroxy acetophenone). Vasilikiotis25

used p-dimethyl

aminobenzaldehyde isonicotinoyl hydrazone as spot test reagent, which forms an

intense orange-yellow precipitate with Mercury (I or II) in slightly acidic, neutral or

slightly alkaline medium.

Manganese (II)26

forms four and six coordinated hydrazone complexes with

isonicotinoyl hydrazone of salicylaldehyde and its 5-methyl, 5-chloro, 5,6-benzo

10

derivatives and 2-hydroxy acetophenone and its 5-methyl, 5-chloro derivatives. The

aldehyde derivative reacts in the keto form while the keto derivative reacts in the enol

form. Both types of ligands are tridentate.

Isonicotinic acid hydrazide (INH) and its acetone derivatives are used for the

spectrophotometric determination of V(V)27

from vanadium-iron alloy and iron-ores.

Fe(III) is masked with NaF. Synthesis and structural studies of some first row

transition metal complexes with acetone isonicotinoyl hydrazones are carried out by

Agarwal and Rao28

.

Teotia

et al29

synthesized and characterized the dimeric, five and six

coordinated complexes of oxo Vanadium (IV) with bi, tri and tetra dentate ligands of

picolinic acid hydrazide, ortho hydroxy acetophenone picolinoyl hydrazone,

isonicotonic acid hydrazide and ortho hydroxyl acetophenone isonicotinoyl

hydrazone.

Kinetics of acid catalysed hydrolysis of 2,4- dihydroxy acetophenone

isonicotinoyl hydrazone is examine by Murali Mohan30

et al and found that the regent

hydrolysed rapidly at pH < 4.

Diacetyl bis (isonicotinoyl hydrazone) is used for the spectrophotometric

determination of Bi (III)31

and also for the spectrofluorimetric studies of

Zr (IV)32

complexes. Aluminium (III)33

is determined spectrophotometrically by

using 2,4-dihydroxy acetophenone isonicotinoyl hydrazone (RPINH). The same

reagent is used for the spectrophotometric determination of Ni (II)34

, Mo (VI) and

Mo (V) 35

.

Kinetics of acid hydrolysis of RPINH in the presence of Zn is carried out

photometrically by Rao et al36

. They also carried out the kinetic photometric

determination of Hg (II) and Ag (I)37

through their catalysis of the reaction between

hexacyanoferrate (II) and isonicotinoyl hydrazide or RPINH or Phenyl hydrazine

11

chloride. RPINH is used for the colorimetric38

studies of Mn (II),Co (II), Ni (II) and

Ti(IV).

Singh et al39

used pyridine -2-carboxaldehyde thio isonicotinoyl hydrazone for

synthetic, structural and anti bacterial studies of Co (II), Ni (II), Cu (II) and Zn (II)

complexes. Salicyaldehyde isonicotinoyl hydrazone is employed as a special

analytical reagent for the selective extraction spectrophotometric determination of

Mo (VI) in presence of several cations by Kalventis40

. He also carried out the

spectrophotometric determination of Antimony (III)41

by using isonicotinoyl

hydrazones of 4-dimethyl amino benzaldehyde and 2-hydroxy-napthaldehyde.

Thorium (IV) and Uranium (VI) 42

are determined in presence of each other

with 2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone spectrophotometrically.

The formation of ternary complex of Fe (III) with isoniazid-2-hydroxy benzaldehyde

hydrazone in a cetyl trimethyl ammonium bromide micellar medium is exploited to

develop simple, sensitive spectrophotometric method for the determination of Fe (III)

by Issopoulos and Economou43

. The colour reaction between Uranium (VI) and 2-

hydroxy-1-naphthaldehyde isonicotinoyl hydrazone in HClO4 acetate buffers is used

to develop a sensitive spectrophotometric method for the determination of

Uranium(VI)44

. A sensitive spectrophotometric determination of Fe (II) in anti –

anaemic pharmaceutical formation using the formation of ternary complex of Fe (III)

with isoniazid-p-diethylamino salicylaldehyde hydrazone in triton X-100 micellar

medium is reported45

. Richardson46

et al reported about the potentiality of iron

chelators of the pyridoxal isonicotinoyl hydrazone class as effective antiproliferative

agents. 2,4-Dihydroxy benzaldehyde isonicotinoyl hydrazone was used for the

spectrophotometric determination of Titanium (IV)47

, Molybdenum (VI)48

,

Thorium (IV)49

and Zirconium(IV)50

.

12

1.1.3: Introduction to Derivative Spectrophotometric methods

The derivative method in UV-Visible and IR spectrophotometry was

introduced in 195351-53

. The initial lack of reasonably priced instrumentation and the

original limitations to the first derivative are the reasons why this technique was

accepted only hesitantly. Since rapid progress in the technology, micro computers has

made to possible to directly present the first, second and higher order derivative

spectra. The great interest towards derivative spectrophotometry (DS) is due to the

increased resolution of spectral bands, allowing detection and location of the

wavelengths of poorly resolved components of complex spectra and reducing effect of

spectral back ground interferences54-56

. Because of these characteristic, the processes

of isolation and pre-concentrations of active components usually required in

qualitative and quantitative spectrophotometric procedures applied in the analysis of

complex systems are avoided.

The conceptual simplicity, relatively peak and easy realization, increased

selectivity and sensitivity in the analysis of minor components are the main reasons

why the interest in the DS is constantly growing. As a result, a great number of

research papers dealing both with the theoretical accept and the appropriate numerical

analysis with detailed critical analysis of derivative techniques of certain order has

appeared. These research papers and review describe the application of DS in

different fields, e.g. pharmaceutical, bio-chemical and environmental analysis,

especially of drugs, food and multi component organic and inorganic mixtures.

General analytical applications UV-Visible derivative spectrophotometry have been

reviewed for the period till 199357,58

.

As with any measurement technique, it is possible that derivative

measurements, if used incorrectly may actually introduce errors larger than would

13

have been observed without its use. A basic understanding of the derivative concept

will minimize this possibility.

1.1.4: Basic characteristics of Derivative Spectrophotometry (DS)

1.1.4.1: Increase of spectral resolution

The main characteristics of DS is to enhance the resolution of overlapping

spectral bands is the consequence of differentiation which discriminates against broad

bands in favor of sharp peak to an extent which increases parallel to the derivative

order55

. This property depends on the intrinsic band width. For two representative

sample band shapes, Gaussian and Lorentzian, which are typical of the type

encountered in practical spectroscopy, the amplitude in the nth

derivative order (nD) is

inversely related to the nth

Power of the band width (W) of the original spectrum.

n

n

WD

1 …………. (1)

Thus, if two bands (X and Y) are of the same intensity, but of different

width, the derivative amplitude of the sharper band (X) is greater than that of the

broader one (Y) by a factor that increases with increasing derivative order

n

x

y

n

n

W

W

YD

XD

)(

)(………… (2)

The relative increase of the amplitude of the sharper band compare to that of

the broader one in higher derivatives represents most important factor responsible for

the increase of sensitivity and selectivity in DS (Fig.1.1).

14

Fig. 1.1: Effect of derivative order (zeroth, second and fourth) on

the relative amplitudes of two coincident Gaussian

bands,

X and Y of equal intensity but with a band width ratio 1:3

1.1.4.2: Enhancement of the detectability of minor spectral features

Derivitisation of broad spectra increases both the possibility of detection and

measurement of minor spectral features and discrimination against interference. Also

it should be kept in mind that derivative transformation of broad spectra does not

increase the number of intrinsic data but visually enhances slight changes in them.

Besides qualitative information, this provides wide possibilities for quantitative

analysis in cases when the main peak is observed by an intensive interfering peak

(Fig1.2) and for analysis of multi component mixtures. Although a great number of

theoretical and practical investigations59-62

have been developed so far, a general

approach to the application of DS in quantitative analysis is impossible, because each

combination of band and degree of their overlapping tends to be an individual case.

15

Fig. 1.2: Reduction in the effect of a curved baseline by the

derivative technique.

(A) Chromophore absorption alone;

(B) Observed absorption of Chromophore superimposed

on base line; (----) base line alone

1.1.4.3: Precise determination of positions of absorption maxima

When a single - peak spectrum has a broad band as its main feature, the

position of the absorption maximum can be only approximately determined. The first

derivative of this band (dA/dλ) posses through zero at the peak maximum, minimum

and shoulder points (Fig1.3) and can be used to accurately locate the peak position15

.

In contrast, the second and higher even derivatives (d2A/dλ

2, d

4A/dλ

4…) contain a

16

peak of changeable (Fig. 1.3) sign (negative in the second order, positive in the fourth

order, etc) which has the same position as a peak maximum in the normal spectrum.

The width of this peak progressively decreases with increasing order of the even

derivative, which causes a sharpening of the peak enabling its exact identification.

However, every even derivative peak is accompanied by symmetrical satellites of the

opposite sign, the number of which is equal to the derivative order.

Fig. 1.3: Characteristic profiles of derivative orders of a Gaussian band

17

1.1.5: Quantitative analysis

The applications of DS for quantitative analysis is based on the same

requirements as normal spectrophotometry, i.e., the validity of Beers law and

additivity of absorbance63

for the derivative spectra of the nth

order at a wavelength λ,

these laws can be represented by the following equations.

cbd

d

d

AdD

n

n

n

nn

………… (7)

...)()()( YDXDTD nnn

... … … (8)

Where A is the absorbance, ε represents the molar absorbitivity, C is the

concentration, b is the path length and nD (T) is the total derivative amplitude, which

is equal to the algebraic sum of each absorbing components X, Y etc. The most

important methods used for the construction of a calibration curve are: peak-peak,

peak-base line, peak-tangent and zero-crossing (Fig.1.4 and 1.5)63-67

. Sometimes

numerical methods of measurement, such as derivation of the ratio spectra are used68

.

The measurement method of choice, in practice, would be the one showing the best

linear depends on the concentration of the analyte, a zero or never zero intercept at the

origin and be the least influenced by the concentration of any other components.

Derivative spectrophotometry is widely applied in inorganic and organic

analysis, toxicology and clinical analysis, analysis of pharmaceutical products, amino

acids and proteins in analysis of food and in environmental chemistry. In general, the

application of derivative spectrophotometry is not limited to any particular case or

field, but can be used whenever qualitative or quantitative investigations of broad

spectra are difficult.

18

Fig.1.4: Graphical measures for amplitudes in derivative spectrophotometry

(p) Peak-Peak method

(t) Peak-tangent method

(z) Peak- zero (baseline) method

Fig. 1.5: Use of the zero-crossing technique to allow quantization one

chromophore (X) overlapped by the absorption band of another chromophore (Y).

19

1.2 : A brief review on hydrazones as spectrophotometric reagents

Hydrazones are azomethines characterized by the presence of the tri atomic

grouping >C=N-N<. They are distinguished from other members of this class (imines,

oximes etc.) by the presence of the two interlinked nitrogen atoms. The hydrazone

group occurs in organic compounds of the types.

R R1 R R1

C=N-N C=N-N=C

X Y X X1

I II

Where

R and R1 = H, Alkyl, Ar, RCO, Ht (Heterocyclic group)

Y = H, Alkyl, Ar, Ht, RCO

X and X1 = H, Alkyl, Ar, Ht, Halogens, OR, SR, CN, SO2R,

NO2, NHNR R’, N = NR, COOR, CONR R’

The general name hydrazone is used for all compounds having structure (I).

The compounds of type (II) are termed “azines”.

1.2.1: Nomenclature

Hydrazones are usually named after the carbonyl compounds from which they are

derived. Thus benzaldehyde and phenylhydrazine give benzaldehyde phenyl

hydrazone. The name originally used was benzylidene phenylhydrazine. Some

authors have revoked to this system, which is, however, cumbersome when applied to

more complex hydrazone. Bis-hydrazones of α-diketones are widely called

“osazones”. The nomenclature widely used in the literature is not in accordance with

IUPAC rules.

20

1.2.2: Preparation

Hydrazones, in general, are prepared by refluxing the stoichiometric amounts

of the appropriate hydrazine and aldehyde or ketone dissolved in a suitable solvent.

The compound usually crystallized out on cooling. Detailed accounts of their

preparation are given in a review69

.

1.2.3: Non-analytical applications

Many of the physiologically active hydrazones find applications70

in the

treatment of several diseases such as tuberculosis, leprosy and mental disorder. On

the other hand aryl hydrazones (III) are reported to possess tuberculostatic71,72

activities. This is attributed to the formation of stable chelates with transition metals

present in the cells.

R-CH=N-NH-CO-R1

III

Thus many vital enzymatic reactions catalyzed by these metals cannot take

place73-75

in presence of hydrazones. Hydrazones also act as herbicides, insecticides,

nematocides, rodenticides and plant growth regulators. They show spasmolytic

activity by potensive action and activity against leukemia, sarcomas and other

malignant neoplasm. Hydrazones are used as plasticizers and stabilizers for polymers

and as polymerization initiators, antioxidants etc. They act as intermediates in

preparative chemistry. Hydrazones of 2-methylphthalazone76

are effective sterilants

for houseflies. 3-N-Methyl-N-(4-chloro-1-phthalazinyl) and 3-N-methyl-N-(4-oxo-1-

phthalazinyl)hydrazones possess anti- helmintic activity77

. The metal chelates of some

hydrazones are useful in industry as dyes and as photometric materials78

.

21

1.2.4: Analytical Applications

Jain and Singh79

reviewed critically the applications of hydrazones as

analytical reagents. The formation of hydrazone is extensively used in the detection,

determination and isolation of compounds containing the carbonyl group. Photometric

methods for determining aldehydes and ketones are based on their reaction with 2,4-

dinitro phenyl hydrazine to form the corresponding hydrazones80, 81

.

Bis cyclohexanone oxalyl di hydrazone gives a blue color with traces of

copper and is used for determination of copper in paper pulp products82

, human

serum83

, steel84, 85

, plants86, 87

, non-ferrous metals and alloys88-90

and in cadmium

sulphide91

. A list of various hydrazones92-308

employed for the determination of

different metal ions are presented in Table 1.4.

22

Table 1.4: A list of hydrazones employed in spectrophotometric determination of metal ions

Name of the reagent Metal ions λmax pH/

medium

Molar

absorptivity(ε)

l.mole-1

.cm-1

Determination

range

Ref

Pyridine-2-aldehyde-2-

pyridylhydrazone(PAPH)

Pd(II) Cu(II)

Zn(II) Cd(II)

Mn(II) Fe(II)

Ni(II)

Fe 405

Pd 560

Basic

ethanol and

water

Acidic

-

Pd 10-100μg

92

93

Pyridine-2-aldehyde-2-quinolyl

hydrazone(PAQH)

Pd(II)

Pd(II)

Co(II)

Ni(II)

594

589

519

492

1.5-2.3

8.0

High

1.2x104

3x104

Co(II)

5.1x104

Ni(II)

0.2-2.0

0.1-1.0

μg/ml

94-99

Qunolline-2-aldehyde-2-quinolyl

hydrazone(QAQH)

Cu(II)

Cu(II)

536

540

-

-

4.7 x 104

5.8 x 104

-

100-102

Qunolline-2-aldehyde-2-Pyridyl

hydrazone(QAPH)

Cu(II)

Ni(II)

Zn(II)

Cd(II)

Pd(II)

512

524

512

517

615

9.0

borate

5.8 x 104

6.2 x 104

5.1 x 104

4.1 x 104

1.6 x 104

-

103-104

Phenanthridine-6-carboxaldehyde-

2- Pyridyl hydrazone(PDAPH)

Cu(II)

Ni(II)

Zn(II)

Cd(II)

Pd(II)

522

530

525

525

625

9.0

borate

7.1 x 104

5.3 x 104

7.0 x 104

7.3 x 104

7.8 x 104

-

103-104

Phenanthridine-2- quinolyl-

hydrazone(PDAQH)

Cu(II) Ni(II),

Zn(II)

Cd(II), Pd(Ii)

536,530

640

9.0

borate

6.6 x 104

15.7 x 104

1.2 x 104

-

103-104

23

2-BenzoylPyridine-2-pyridyl

hydrazone(BPDH)

Fe(II)

Co(II)

Ni(II)

Cu(II)

-

-

-

Fe 0.3

Co 0.2

Ni 0.13

Cu 0.14

105-106

Di-2pyridyl methanone-2-thio phene

carboxylic hydrazone (DPMTCH)

Ni (II)

417

-

4.17 x 104

0 to1.17

107

2,2’-Dipyridyl-2-hydrazone(DPPH)

Cu(II)

Zn(II)

V(V)

Pd(II)

Co(II)

Fe(II)

Fe(III)

-

480

538

-

3-11

1.5-3.5

-

3.2 x 104

1.5 x 104

-

0.15-2.0

0.7-2.8

108

109

110-114

Phynyl pyruvic acid-2-

quiolylrazone(PPAQH)

Cu(II)

-

12.0

-

-

114,115

Benzoyl salicylalhydrazone(BSH)

Cu(II)

Pd(II)

-

385

395

4.9-9.0

4.5-6.5

1.2-2.3

-

1.55 x 104

7.18 x 104

-

-

116

117

Pyridine-2-aldehyde-1-thionaphthal

hydrazone(PATNH)

C(II)

480

1M HCl

6.35 x 103

-

118,119

2-Benzothiazolylhydrazone-2-

thiophinaldehyde(TBTH)

Cu(II) 422 5.1 4.4 x 104

Up to

12 μg

120

5-Methyl furfural-2-benzthiozolyl-

hydrazones(MFBH)

Cu(II)

405-415

-

5.8 x 104

0-12 μg

121

1-Napthaldehyde-2-benzothiozolyl

hydrazone(NBTH)

Cu(II)

422

6.9-9.7

phosphate

buffers

4.8 x 104

-

122

24

Furfural-2-benzthiozolyl-

hydrazones(FBTH)

Ag(I)

Co(II)

Cu(II)

Hg(II)

Ni(II)

Zn(II)

989

408

415

389

405

418

6.5-9.2

9.9-11.2

5.6-9.6

5.0-10.4

11.0-11.6

9.4

2.6 x 104

5.1 x 104

4.4 x 104

0.5 x 104

4.5 x 104

0.8 x 104

-

123

o-Hydroxybenzaldehyde

isonicotynoylhydrazone

Al(III)

Ga(III)

In(III)

Tl(III)

Ni(II),Zn(II)

Mn(II),Cd(II)

375

390

380

-

380

420

5.0

12.7 x 103

3.4 x 104

3.3 x 104

-

1.5 x 104

2.5 x 104

0.5-3.5

0.2-1.6

0.3-2.5

-

124

125

126-128

o-Hydroxy benzaldehyde benzoyl

hydrazone(BBH)

Zn(II)and

Mn(II)

380

400

- 1.35 x 104 -

125

p-Dimethyl amino Benzaldehyde

isonicotinoylhydrazone(DAIH)

Hg(I) or

Hg(II)

-

Slightly

acidic

(or)neutral

(or)

slightly

alkaline

-

40 μg

(I or II)

129

4-Hydroxybenzaldehyde

isonicotinoylhydrazone

V(V) - In acidic

50% ethanol

- - 130

2-Hydroxy-1-napthaldehyde2-

benzothiozolyl hydrazone

Cu(II) 426 5.3-9.5 2.2 x 104 Up to24 μg 131

Bis(6-methyl-2-pyridyl)glyoxal di

hydrazone

Cu(II),Pd(II)

Co(II)

420

4.8-11.2

8.7 x 103

-

132

6-Methyl picolinaldehyde-

hydrazone

Cu(I)

Pd(II)

425

-

-

-

7 x 103

-

1-7ppm

-

133

134

25

Benzyl-bis-2-pyridyl hydrazone Cu(II),Zn(II),

Co(II), Fe(II)

Ni(II)

-

-

-

-

135

2,2’-Pyridyl-2-pyridyl hydrazone Cu(II),Zn(II),

Co(II)Fe(II)

Ni(II)

-

-

-

-

135

Benzil mono-(2-pyridyl)hydrazone Co(II) 535 Ethanolic 2.7x104 - 136

Bicyclohexanone oxalyldihydrazone Cu(II) 600 7.0-9.0 1.6x104 - 137-139

Bis(ethylacetoacetate) oxalyl hydrazone Cu(II) 585 9.0 1.39x104 - 140

Bis-(4-hydroxy benzoyl hydrazone) of

glyoxal, methyl glyoxal and dimethyl

glyoxal

Ca(II),Cd(II)

La(III),Bi(III)

-

-

-

0-50

141

142

β- Resorcylaldehyde acetyl hydrazone

Fe(III),U(VI)

Ti(IV),Co(II)

Iron(III)

-

-

-

-

143

o-Hydroxy acetophenonehydrazone Ni(II) 425 10-10.5 7.25x102 Up to11.6

ppm

144

Diacetylmonoxime-2-benzothiozolyl

hydrazone

Pd(II) 560 1.8

NH3

5.11x103

Up to

15ppm

145

Gossypol isonicotynoylhydrazone UO2(II) 440 3.0 - 3-12 146

Ethyl diketobutyrate2-

hydroxyphenylhydrazone

Co(II)

Cr(III)

565

8-9

- -

147

Benzil di-2-pyridylhydrazone

Ni(II)

Cu(II)

Co(II)

Fe(II)

497

430

531

635

-

4.9x103

5.4 x103

4.6 x103

5.8 x103

-

148

2,2’-Pyridil mono-2-pyridylhydrazone Fe(II) 621 - 1.30 x104 - 148

26

2,2’-Pyridyl di-2-pyridylhydrazone

Fe(II)

Cu(I)

Co(II)

Ni(II)

595

466

480

452

-

8.30 x103

2.03 x104

2.54 x104

3.20 x104

-

148

2,2’-Dipyridyl-2-pyrimidylhydrazone Co(II) 460 2.5-11.5 2.95 x104 - 149

Pyridine –2-aldehyde-2’-

pyridylhydrazone

Mn(II) - - 5.71 x104 150

Dibenzylidene thiocarbo hydrazide

(DBTCH)

Ru(III) 530 5.2-6.5 1.326 x 104 1.0-7.0 151

Bis (thiophene-2-aldehydo)

thiocarbohydrazone (BTATCH)

Ru(III)

Ir(III)

540

380

HCL

medium

5.6-6.6

1.6 x 104

3.2 x 104

0.7-3.5 ppm

1.2-4.2

152

2,2’-Dipyridyl-2-

quinolylhydrazone(DPQH)

V(V) 550

580

3.7-5.9

5.0-13.0

2.28 x104

1.25 x104

Up to 2.29 153

Benzothiozole-2-aldehyde-2-

quinolylhydrazone

Cu(II)

Pd(II)

-

-

8.3-12.6 7.5 x104 0.09-0.75 153

2,2’-Dipyridyl ketone-2-

pyrimidylhydrazone

Fe(II) 540 1.5-2.5 1.15 x104 Up to 5.0 154

2-Methyl isonicotinic

Salicylalhydrazone

Ti(IV) 425 1.0-2.5 - - 155

Pyridoin phenylhydrazone Cu(II)

- 4.3-5.8 2.05 x104 0.25-2.25 156

Picolinaldehyde-p-

nitrophenylhydrazone

Pd(II) 480 - 9.5 x103 3.0-9.0 157

Di-2-pyridyl glyoxal-2-

quinolylhydrazone

Fe(III) - 6.0-10.5 3.2 x104 Up to 2.0 158

5-Chloro-2-thiophenaldehyde-2’-

benzothiazolylhydrazone

Co(II) - 7.2-9.1 7.6x104 0-180 159

27

2,2’-Dipyridyl-2-pyrimidylhydrazone Co(II) - 2.5-.5M

HCLO3

3.13 x104 <2.1 160

2,2’-Bipyridyl glyoxal-2-

quinolylhydrazone

Co(II) - 4.0-8.0 3.2 x104 0.24-1.92 161

Salicylaldehyde hydrazone Pd(II)

Os(VIII)

425

430

3.5-5.0

9.5-10.0

5.3 x103

3.2 x103

Up to21

Up to19.7

162

2-hydroxy-1-napthaldehyde

isonicotinoylhydrazone (2HNAINH)

U(VI)

430

3.0

9.6 x 103

0.2-33

163

O-Hydroxypropiophenone

isonicotinoylhydrazone

U(VI) 580 3.0 1.15 x 104 0.47-17 164

Pyridine –2-aldehyde-2-

pyridylhydrazone

Co(II)

-

5.6

8.26 x104 in

CHCl3

1.15 x104 in

nitrobenzene

0.04-0.4

165

2-Thiophenealdehyde-2-

benzothiazolylhydrazone

Cu(II)

Ni(II)

Co(II)

430

410

413

4.5-12.5

4.4 x104

4.1 x104

6.3 x104

-

166

Di-2-pyridylmethanone-2-

pyrimidylhydrazone

Zn(II) 430 7.9-11.1 5.2 x104 Up to 1.56 167

Di (2-pyridyl)glyoxal-2-

quinolylhydrazone

Pd(II) 470

570

8.0-11.0

2.0-6.5

1.5 x104

1.08 x104

1.07-7.4

1.06-6.0

168

2,2’-Diquinolylketone-2-pyridyl-

hydrazone

Pd(II) 624 2.0

CHCl3

1.95 x104

0.25-5.0 169

Diphenyl glyoxal bis-(2-hydroxy

benzoyl)hydrazone

Ti(IV) 500 0.1N

H2SO4

1.5 x104

0.5-2.5 170

3-Aldehydrosalicyledene

cyanoacetylhydrazone

Fe(III) 370 4-5 1.292 x103 - 171

Di-2-pyridyl glyoxal-2- Cu(II) - 2.5-9.6 3.5 x104 Up to2.27 172

28

quinolylhydrazone

2,2’-Pyridyl bis(2-quinolylhydrazone) Pd(II) 550 3.5-6.6 1.28 x104 1.0-8.5 173

2-Pyridylaldehyde-2-pyridal-hydrazone

Fe(III) - 9.0 - 2.0-16.0 174

2,2’-Dipyridyl-2’-pyridylhydrazone

Co(II)

480

500

3-11

strong acid

4.2 x104

>1ppb

175

2,2’-Dipyridyl-2-quinolylhydrazone

Pd(II)

Fe(III)

Co(III)

Zn(II)

Hg(II)

Cu(II)

Cd(II)

570

604

645

566

475

528

510

505

505

511

0.2-0.9M

HCl

3.4-4.5

H2SO4

7.6-9.1

7.6-11.6

8.0-12.7

12.5-13.5

1.75 x 104

2.21 x 104

1.3 x 104

3.11 x 104

3.61 x 104

4.8 x 104

8.21 x 104

6.37 x 104

5.04 x 104

8.78 x104

-

176

Diphenyl glyoxal bis(2-

hydroxybenzoyl)hydrazone

Ti (IV) 500 0.1 N

H2SO4

1.5 x104 0.5-2.5 177

2,2’-Dipyridyl-2-pyridylhydrazone Cu (II)

Zn (II)

-

448

11.9-12.6

-

3.8 x104

-

Up to 1.0

0-10

178

179

2-Furaldehyde-2-pyridylhydrazone Pd(II) 430 8.0-8.5 - 0.5-2.5 180

2,2’-Dipyridyl-2-guinolylhydrazone Fe(III) - 3.4-4.5 3.4 x104 Up to 1.4 181

Pyridine-2-acetaldehyde

salicylhydrazone

Fe(III)

-

CHCl3 - 2.7-16.0 182

Pyridoxal salicylalhydrazone Ti(IV) 450 0.9-2.5 0.39 x104 0-10.0 183

Pyridoxal-3-hydroxy-2-

naphthalhydrazone

Ti(IV) 430 2.7 - 0.5-7.0 184

Pyridoxal nicotinoylhydrazone Ti(IV) 410 2.1-2.3 0.69 x104 - 185

29

Pyridoxal-2-pyridylhydrazone V(V) 430 1.7-1.9 1 x104 - 186

2-Thiophenoldehyde-2-

quinolylhydrazone

V(V) 425 1:1

HCl

- - 187

2-Aceto-1-naphthol-N-salicylhydrazone Mn(II) - - - - 188

3-Bromo-2-hydroxy-5-methyl

acetophenonehydrazone

Cu(II)

Co (II)

-

-

5.0-6.0

2.0-6.0

4.8 x103

-

0.13-2.75

0.62-6.22

189

190

2,2’-Dipyridyl ketonehydrazone

Pd(II)

500 13.4 80%

ethanol

- 0.5-4.0 191

2,2’-Dipyridyl benzo

thiazolylhydrazone

Fe(III) - 4.5-8.4 3.41 x104 0.1-1.6 192

Di(2-pyridyl)methylene-2-

furoylhydrazone

Fe(III) - 9.6 8.4 x103 1.0-6.0 193

3-(Picolinoyl)benzene sulphuricacid-2-

hydroxybenzoylhydrazone

V(V) - - - - 194

2,2’-Dipyridyl-ketone-2-

quinolylhydrazone

V(V) - Acidic - Up to1.5 195

1,2-Cyclohexane dione(bisbenzoyl)

hydrazone

Ti(IV) 477 1.75-3.0 1 x104 1.7-3.0 196

N-Cyanoacyl acetaldehydehydrazone Mo(VI)

V(V)

790

410

-

-

-

0.77 x104

-

22-49.0

197

Resacetophenone

isonicotinoylhydrazone

Mo(VI) - - - - 198

3,4-Dihydroxy benzaldehyde

gunylhydrazone

Mo(VI) - - - - 199

2-hydroxy-1-naphthaldehyde

guonylhydrazone

V(V) 405 - 0.77 x104 0.7-8.2 200

Anthranilic acid resocylaldehydrazone V(V) 410 4.5 1.35 x104 - 201

2,6-Diacetylpyridine bis(benzoyl- V(V) 335 2.6-4.0 2.74 x104 - 202

30

hydrazone)

2,6-Diacetylpyridine bis(2-hydroxy

benzoyl-hydrazone

V(V) 336 2.6-3.5 2.77 x104 - 202

Thiazole-2-carboxaldehyde-2-

guinolylhydrazone

Pd(II) 588 C2H6 1.93 x104 - 203

2-Pyridyl-3’-sulfophenylmethanone-2-

(5-nitro)pyridylhydrazone

Co(II) - - 5.69 x104 0.05-1.0 204

2(-3’-sulfobenzoyl)pyridine

benzoylhydrazone

Co(II) - 1.5M

HClO4

2.17 x104 - 205

Salicylaldehyde isonicotinoylhydrazone Mo(VI) 430 0.65 - 0.4-12.0 206

3,5-Dichloro-salicylaldehyde-2-

benzothiozolylhydrazine

Mn(II) 460 3.0-4.8 - Up to 60 207

2(-3’-sulfobenzoyl)pyridine

benzoylhydrazone

Fe(III) - 7.0-11.0 - Up to 4.0 208

Resacetophenone oxime salicylic acid

hydrazone

V(V) 450 Acetic acid 6 x104 0.5-4.0 209

2,4-Dihydroxy benzophenone

benzoylhydrazone

Ce(IV) 400 8.0-10.5 2.0 x104 0.3-7.0 210

Di-2-pyridylketone-2-pyridyl-hydrazone V(V) 545 - 1.4 x104 - 211

Pyridine-2-acetaldehyde

salicylolylhydrazone

Ni(II) 395 4.0-7.0 8.51 x103 0.5-5 212

Bis(thiophene-2-aldehyde)

thiocarbohydrazone

Ru(III)

Ir(III)

540

380

0.3-0.7N

5.6-6.6

1.6 x104

2.2 x104

0.7-3.5

1.2-4.2

213

2-Hydroxy-1-acetonaphthone salicylic

acid hydrazone(HANSH)

V(IV)

V(V)

U(VI)

Zr(VI)

Th(IV)

Mo(VI)

410

410

310

402

400

350

4.0

5.0

8.0

1.0

6.0

CH3COOH

1.22 x104

1.4 x104

0.78 x104

2.6 x102

1.1 x104

5.4 x103

0.5-5.0

0.5-5.0

0.6-3.0

18-180

46-460

10-100

214

31

2-Hydroxy-1-acetonaphthone salicylic

acid hydrazone(HANSH

Cu(II)

Ni(II)

Cr(VI)

400

410

412

Acid

alkali

HCl

1.1 x104

8.0 x104

1.3 x104

0.8-5.4

12-60

1-10

214

2,4-Dihydroxy acetophenone

benzoichydrazone

Mn(II)

V(V)

450

380

8.0-11.0

3.0-3.5

1.0 x104

1.3 x104

0.3-7.0

0.3-5.0

215

Ortho-hydroxy acetophenone

isonicotinoylhydrazone

V(IV)

Ti(IV)

390

380

Acidic

4.0

1.0 x104

2.0 x104

1.0-30.6

1.2-14.4

216

2,4-Dihydroxy benzophenone

benzoichydrazone

Cu(II)

Fe(III)

380

380

4.0

5.0

1.55 x104

2.8x104

0.31-2.2

0.14-0.38

217

2,4-Dihydroxy benzophenone

benzoichydrazone

V(V)

Mn(II)

390

455

9.0-9.5

2.0 x104

2.5 x104

-

-

218

2,4-Dihydroxy benzaldehyde

isonicotinoylhydrazone

Ti(IV) 430 1-7 1.35 x104 0.09-2.5 219

Di-furfuralthiocarbohydrazone

Rh(II)

Pd(II)

Os(VI)

Ir(III)

377

330

377

380

5.6-6.7

4.0-6.0

5.9-6.7

5.5-6.2

6.1 x104

4.48 x104

3.62 x104

4.15 x104

0.48-2.4

0.34-1.44

1.0-4.2

0.93-3.23

220

221

5-Chloro salicylaldehyde

guanylhydrazone

Pd(II) 400 7.5-9.0 0.7129 x104 0-6.0 ppm

222

2-Hydroxy acetophenone

benzoylhydrazone(HABH)

V(V) 375 CH3COOH

0-0.5M

8.93 x103 0-3.5 223

2,4-Dihydroxy benzaldehyde

isonicotinoylhydrazone

Mo(VI)

V(V)

Fe(III)

Ni(II)

445

440

400

400

1.0-3.0

2.0

3.0

6.0

1 x104

15 x104

1.75 x104

4.0 x104

0.30-6.14

0.1-2.0

0.08-1.9

0.08-1.0

224

225

226

2,4-Dihydroxy benzaldehyde Cu(II) 430 2.0 1.65 x104 0.063-2.55 224

32

isonicotinoylhydrazone

2-Hydroxy acetophenone

Benzoylhydrazone

V(II) 465 Acitic acid 1.05 x104 0-1.5

227

2,5-Dihydroxy acetophenone

benzoichydrazone

Cu(II)

V(V)

400

405

5.0

5.5

1.1 x104

1.05 x104

0.3-3.0

0.25-2.5

228

229

Resacetophenone

isonicotinoylhydrazone

Mn(II) 465 9.4 0.8 x104 Up to 4.4 230

Acetoactanilide salicylhydrazone V(V) 400 Acidic 4.38 x103 - 231

9,10-Phenanthraquinone

guanyl hydrazone

Ni(II)

Os(VII)

Te(IV)

500

515

370

9.4

6.4

7.68

1.029 x104

0.6591 x104

1.9748 x104

0-18 ppm

0-14 ppm

0-60 ppm

232

233

234

Isonitraso acetylacetone

benzoylhydrazone

Ni(II)

390-400 10.0 1.1309 x104 0.09-3.0 235

Benzyl α-monoxime

isonicotinoylhydrazone(BMIH)

Ni(II)

Pb(II)

Cu(II)

Cd(II)

398

405

346

364

8.5

10.5

8.5

8.5

1.45 x104

1.18 x104

1.19 x104

2.5 x104

0.12-2.82

0.41-13.3

1.01-5.08

0.45-4.5

236

237

238

Diacetyl monoxime

isonicotinoylhydrazone(DMIH)

Ni(II)

Pb(II)

Cd(II)

Cu(II)

366

374

346

346

8.25

10.5

9.0

8.5

1.75 x104

1.25 x104

2.0x104

1.12 x104

-

-

-

-

238

239

Diacetyl monoxime

benzoylhydrazone(DMBH)

Ni(II)

Pb(II)

Cd(II)

Cu(II)

362

372

348

346

9.0

10.5

9.5

9.0

2.125 x104

1.25 x104

1.6 x104

1.36 x104

-

238

240

V(V) 430 3.0 1.6 x104 241

33

2-Hydroxy napthaldehyde benzoic

hydrazone(OHNABH)

Cu(II)

Fe(III)

Co(II)

Ni(II)

410

410

465

455

5.0

5.0

5.0

5.0

2.27 x104

2.24 x104

3.7 x104

3.18 x104

-

2,4-Dihydroxy benzaldehyde

isonicotinoylhydrazone

Co(II)

Fe(III)

Al(III)

Zn(II)

-

-

-

-

242

243

244

2-Hydroxy 1-napthaldehyde

isonicotinoylhydrazone (OHNAINH)

Al(III)

Zr(IV)

Pd(II)

Ti(IV)

425

455

490

410

4.5

2.0

10.0

4.0

3.016 x104

1.69 x104

3.82 x104

1.54 x104

-

245

Bis Vanalin Thiocarbohdrazide (BVTH) Hg(II)

Cu(II)

390

384

1.0-6.0

4.0-6.0

5.5 x104

3.05 x104

0.241-2.8

0.08-0.84

246

Diacetyl monoxime

isonicotinoylhydrazone(DMIH)

Fe(III)

Fe(II)

Co(II)

366

360

334

4.5-5.5

6.0-7.0

6.0-7.0

1.3 x104

1.25 x104

1.25 x104

0.11-2.24

0.22-2.24

0.24-2.35

247

246

248

Diacetyl monoxime benzoylhydrazone

(DMBH)

Fe(III)

Fe(II)

368

360

5.0-5.5

6.0-6.5

1.16 x104

1.25 x104

0.11-2.40

0.11-2.24

246

5-methylsalcilaldehyde

guanylhydrazone

Mn(II) 415 8.5 7.409 x 103 0-10 ppm 249

1,5-diphenylcarbuhydrazide Ni(II) 495 - 1.588 x 105 - 250

Pyridoxal-4-hydroxy benzoylhydrazone Zr(IV) 418 3.5 2.46 x 104 0.1-3.5 251

5-Chloro-2-hydroxy thiobenzhydrazide Rhenium - - - - 252

Di-2-pyridylketone benzoylhydrazone Ni(II) - 60 - - 253

2-Acetothiophene guanylhydrazone Pd(II) 375 - 0.749 x 104 0-12 ppm 254

2-Hydroxyacetophenone V(V) 375 AcOH 8.93 x 103 0-3.5 255

34

benzoylhydrazone

2-Hydroxynapthaldehyde

guanylhydrazone

Cu(II) 390 4.3 8.089 x 103 0-4 ppm 256

Furan-2-carboxylicacid

Propylidenehydrazide

Co(II)

Ni(II)

Cu(II)

-

-

-

-

257

Pyridine-2-acetaldehyde

salicyloylhydrazone (PASH)

Sb(III) 405 - 1.94 x 104 1.5-5.0 mg/ml 258

Di-2-pyridylketone benzoylhydrazone

(DPKBH)

Ni(II) 406 - - 0.3-9.4

259

p-methylisonitroso acetophenone-

hydrazone

Ni(II)

Co(II)

480

520

7.5

7.5

4.87 x 103

1.83 x 103

0.2-20

0.2-6.0

260

261

O-Aminoacetophenone

benzoylhydrazone

Cd(II)

Cu(II)

Co(II)

Ni(II)

-

-

-

-

262

Resacetophenone guanylhydrazone

(RAG)

Ru(II)

Ag(I)

375

440

1.5

10.1

0.7469 x 104

0.337 x 104

0-35 ppm

0-30 ppm

263

264

2-Hydroxybenzaldehyde-5-nitro

pyridylhydrazone

Fe(III)

V(IV)

Co(II)

-

-

5.0

-

-

-

0.05-2.0

-

265

266

267

5-Chlorosalciladehyde guanylhydrazone Pd(II) 400 8.1 0.7129 x 104 0-6.0 268

2,3,4-Trihydroxy acetophenone

salicylhydrazone

V(V) 410 - - - 269

3,5-Dimethoxy-4-hydroxy-2- 270

35

aminoacetophenone

isonicotinoylhydrazone

Au(III) 490 6.0 3.45 x 104 0.30-4.0

2-Hydroxy acetophenone

benzoylhydrazone

V(V)

Mo(VI)

V(III)

422

443

465

-

-

AcOH

7.7 x 104

2.59 x 104

1.05 x 104

0.1-15

0.-30

0-15

271

272

2,4-DiHydroxyacetophenone

IsonicotinoylHydrazone (RPINH)

Ti(IV)

Pd(II)

Zr(II)

V(IV)

Ru(III)

Al(III)

490

420

415

400

415

370

1.0-2.0

5. 0

1.5

4.0

3.0

4.5

1 x104

1.4 x104

1.7 x104

0.89 x104

10.3 x104

2.5 x 104

0.47-3.35

0.53-6.3

0.23-3.19

0.26-3.05

0.02-0.39

0.1-1.3

273

274

2,4-dihydroxybenzaldehyde

isonicotinoylhydrazone

Mo(VI)

Th(IV)

Zr(IV)

- - - - 275

276

277

2- aminoacetophenone

isonicotinoylhydrazone

Au(III)

Pd(II)

V(V)

Co(II)

Cu(II)

- 4.0 - -

278

279

2,4-dihydroxybenzaldehyde

isonicotinoylhydrazone

Mo(VI)

Ti(IV)

- - - - 280

281

2-hydroxy1-napthaldehyde

benzylhydrazone

V(V)

Cu(II)

- 5.0 - - 282

283

Di-2-Pyridyl Ketone alicyloylhydrazone Zn(II) 376 4.5 4.8 x 104 - 284

Cinnamaldehyde isonicotinoyl

hydrazone

Co(II)

Mo(VI)

Ru(III)

Cd(II)

390

394

402

380

8.5

3.0

3.0

8.5

5.5 x 104

3.12 x 104

1.25 x 104

3.3 x 104

0.03-0.71

0.19-1.92

0.20-4.04

0.22-4.50

285

Diacetylmonoxime-4-hydroxy Cu(II) 380 9.0 2.0 x 104 0.12-2.35 285

36

benzoylhydrazone Ni(II) 396 10.0 1.8 x 104 0.06-1.27

Sn(II) 430 - 3.2 x 104 0.25-2.76 286

Cd(II)

Co(II)

Pb(II)

412

414

440

10.5-11.0

10.0-10.5

10.0

3.27 x 104

1.9 x 104

1.71 x 104

0.05-0.79

0.06-1.47

0.41-10.4

287

288

N- ethyl 3- carbazole carboxaldehyde

thiosemicarbazone

Pd(II) - 4.0 1.647 x 104 - 289

4[N,N- (diethyl) amino] benzaldehyde

thiosemicarbazone

Pt(IV) 405 - 1.755 x 104 - 290

4[N,N- (diethyl) amino] benzaldehyde

thiosemicarbazone

Cu(II)

- - - - 291

3,4- Dihydroxy benzaldehyde

isonicotinoyl hydrazone

Pd(II) 380 3.0 0.53 x 104 0.5-20 292

3- methoxy 4- hydroxyl benzaldehyde

4- bromo phenyl hydrazone

Cu(II)

462 - 2.052 x 104 0.2-4.0 293

Resacetophenone hydrazone Hg(II) 430 3.0 0.1086-0.9774 294

4-hydroxy 3,5-dimethoxy benzaldehyde

4 hydroxy benzoyl hydrazone

Pd(II) 373 3.0 7.5 x 104 0.106-1.064 295

3-methoxy salcilaldehyde 4-hydroxy

benzoyl hydrazone

Th(IV) 394 4.25 2.0 x 104 0.232-4.641 296

3,5 Dimethoxy 4-hydroxy isonicotinoyl

hydrazone

Pd(II) 382 5.5 2.44 x 104 0.1064-2.1284 297

N,N,N’,N’- tetra(2- ethyl hexyl)-thio

diglycolamide

Pd(II) 300 1.29 x 105 1.0-15.0 298

Diacetyl monoxime isonicotinoyl

hydrazone

Hg(II) 351 5.5 2.23 x 104 1.003-12.03 299

Salicyl aldehyde aceto acetic acid

hydrazone

Cu(II)

2.0 22.5 x 104 0.0499-0.4994 300

Cinnamaldehyde 4 hydroxy benzoyl Cu(II) 375 9.0 2.77 x 104 0.158-1.588 301

37

hydrazone

4-hydroxy 3,5 dimethoxy benzaldehyde

4- hydroxy benzoyl hydrazone

Fe(III) 380 5.0

1.71 x 104 0.279-2.79 302

2-pyridine caroxylaldehyde

isonicotinoyl hydrazone

Ni (II)

Cu(II)

Co(II)

Fe(III)

363

352

346

359

-

8.4 x 104

5.2 x 104

7.1 x 104

3.9 x 104

-

303

2-hydroxy 5-methyl 3- nitro

acetophenone oxime

Co(II)

420 7.0-8.0 1.4725 x 104 0.1-6.0 304

Potassium isobutyl xanthate Fe(III)

378 2.58 x 103 2.5-35 305

Cinnamaldehyde 4 hydroxy benzoyl

hydrazone

Mo(VI) 404 3.0 6.82 x 104 0.047-0.479 306

4-hydroxy 3,5 dimethoxy benzaldehyde

4- hydroxy benzoyl hydrazone

Ru(III) 400 4.0 1.79 x 104 0.252-5.053 307

3,5 dimethoxy 4- hydroxy

benzaldehyde isonicotinoylhydrazone

Pb(II) 430 9.0 1.82 x 104 0.414-10.360 308

38

1.3: Objectives of present investigation

Analytical methods play a vital role in checking the composition of the raw

material and finished products and in the analysis of environmental pollution, etc. The

analytical chemistry of certain metal ions like Copper is an important metal in

biochemical processes.

Chromium compounds are widely used in the chemical industry as ingredients

and catalysts in pigments, metal plating and chemical synthesis. Cr (VI) can also be

produced when welding on stainless steel or Cr (VI)-painted surfaces.

Cadmium was a soft, malleable, ductile, bluish-white bivalent metal. It was

similar in many respects to zinc but forms more complex compounds. About three-

quarters of all the cadmium is used in batteries, predominantly in rechargeable

Nickel-Cadmium batteries, Cadmium was discovered in Germany in 1817 by

Friedrich Stormier.

Mercury is available in nature in the free state in the form of sulphides,

chlorides and carbonates. Mercury is so volatile that it could be exposed easily to

human environment. It would cause a neurological damage and even result in death.

Generally, the concentrations of Hg (II) in environmental samples are relatively low

unless exposed in some industrial area. Total mercury concentrations in natural waters

ranged from 0.2 to 100 mg L−1

.

Lead is a cumulative poison that enters the body from lead water pipes, lead-

based paints and leaded petrol. The determination of trace amount of lead is very

important in the context of environmental monitoring.

Hydrazones are important class of analytic reagent for spectrophotometric

determination of metal ions. In general, each type of organic reagent has one or more

39

functional groups. It should be of interest to design, synthesize and use a new ligand

containing poly-functional groups. As ligands possessing mixed functions, one or

both are expected to show good analytical properties.

The present research work focuses on the synthesis and characterization of

new organic reagents and spectrophotometric determination of metal ions using new

organic reagents.

In the light of above, the objectives of present investigation are as follows.

Research methodology followed

Synthesis and characterization of new organic reagents

a) 2,4-Dimethoxybenzaldehyde-4-hydroxybenzoylhydrazone(DMBHBH)

b) 2,4-Dimethoxybenzaldehydeisonicotynoylhydrazone(DMBIH)

To investigate the analytical properties of new reagents

Aimed to develop sensitive zero order and derivative (First and second

derivative) spectrophotometric methods for the determination of Cu (II),

Cr (VI), Cd (II), Hg (II) and Pb (II) employing above reagents.

Importance of present investigations

The precise determination of metal ions at micro gram level in the area of

analytical chemistry has given added impetus to the analytical chemistry to discover

simple, speedy and accurate methods. Moreover, the choice of selecting suitable

method from the innumerable methods present in the literature has also become

difficult. Thus, inspite of the availability of new methods and modern technique for

the determination of metal ions, the demand for newer methods of analysis is

40

increasing in view of the problems constantly faced by the analytical chemists from

the complexity of the materials coming up for analysis.

Although strong claims are made for the specificity and sensitivity of atomic

absorption, plasma atomic emission analysis and atomic fluorescence emission, some

of the interference to which these methods are subjected to poorly understand and

continue to cause problems. Further, these techniques are not within the reach to

many laboratories. Besides the cost involved they are not amenable to easy

operations.

In this context spectrophotometry, a widely employed analytical technique is

more popular because of the common availability of instrumentation and simplicity

procedures as well as speed, precision and accuracy resulting in extensive literature

being published every year. The advantage of new generation spectrophotometers

equipped with diode array detectors and extensive use microprocessors in data

acquisition and handling have brought about dynamic progress.

Spectrophotometric analysis of metal ions at microgram level involves

synthesis of selective and sensitive reagents. Among the numerous organic

photometric reagents used, hydrazones occupy a special place due to their good

chelating properties with the metal ions to form stable as well as characteristic

complexes.

Among the hydrazone derivatives, (substituted benzoyl hydrazones) 4-hydroxy

benzoyl hydrazones and isonicotinoyl hydrazones are potential analytical reagents

due to their ability to form insoluble complexes and to produce characteristic

absorption spectra when reacted with metal ions. Thus they serve as better separating

reagents, even at sub-microgram level.

41

This necessitates the development of more or less complicated procedures to

overcome this detrimental influence. Therefore, in order to achieve greater degree of

selectivity, the emphasis is being devoted to develop direct and derivative

spectrophotometric procedures for the metal ions when present in a mixture.

Derivative spectrophotometric procedures for the determination of metal ions are

meagerly reported in the literature. In addition, derivative spectrophotometry is an

excellent back ground elimination technique which enables the exact determination of

λmax of the particular analytic species and facilities the detection of poorly resolved

peaks and also increases the sensitivity and enhances the selectivity of the

spectrophotometric procedures.