Research Article Synthesis, Spectral, and In Vitro ...downloads.hindawi.com/journals/bca/2013/425832.pdfOrganosilicon(IV) Complexes with Schiff Bases Derived from Amino Acids HarLalSingh,JangbhadurSingh,andA.Mukherjee

Hindawi Publishing CorporationBioinorganic Chemistry and ApplicationsVolume 2013 Article ID 425832 9 pageshttpdxdoiorg1011552013425832

Research ArticleSynthesis Spectral and In Vitro Antibacterial Studies ofOrganosilicon(IV) Complexes with Schiff Bases Derived fromAmino Acids

Har Lal Singh Jangbhadur Singh and A Mukherjee

Department of Chemistry Faculty of Engineering and Technology Mody Institute of Technology and Science LakshmangarhSikar Rajasthan 332311 India

Correspondence should be addressed to Har Lal Singh hlsingh9rediffmailcom

Received 21 April 2013 Revised 29 June 2013 Accepted 2 July 2013

Academic Editor Imre Sovago

Copyright copy 2013 Har Lal Singh et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The present work stems from our interest in the synthesis characterization and antibacterial evaluation of organosilicon(IV)complexes of a class of amino-acid-based Schiff base which have been prepared by the interaction of ethoxytrimethylsilane withthe Schiff bases (NOH) in 1 1 molar ratioThese complexes have been characterized by elemental analysis molar conductance andspectroscopic studies including electronic IR and NMR (1H 13C and 29Si) spectroscopy The analytical and spectral data suggesttrigonal bipyramidal geometry around the silicon atom in the resulting complexes The ligands and their organosilicon complexeshave also been evaluated for in vitro antimicrobial activity against bacteria (Bacillus cereus Nocardia spp E aerogenes Escherichiacoli Klebsiella spp and Staphylococcus spp) The complexes were found to be more potent as compared to the ligands

1 Introduction

In the last decade coordination and organometallic com-pounds of biologically active ligands [1ndash3] have receivedmuch attention However it is notable that the biologicalactivity of Schiff bases was significantly enhanced on chela-tion It has been reported that chelation is the cause and cureof many diseases including cancer Schiff base complexes [4ndash7] have found antibacterial antifungal anticancer tubercu-lostatic and herbicidal activities [8ndash12] The current researchdealing with metal complexes of heteronuclear Schiff baseshas expanded enormously and includes diversified subjectscomprising their various aspects in biocoordination andbioinorganic chemistry It is known that the presence ofmetalions bonded to biologically active compounds may enhancetheir activity [13ndash16] Heteronuclear Schiff base complexeshave found applications as magnetic materials catalystsand in the field of bioengineering [17 18] Organosiliconcompounds of nitrogen and sulphur containing ligands arewell known for their anticarcinogenic antibacterial tubercu-lostatic antifungal insecticidal and acaricidal activities [19ndash22] The interest in organosilicon(IV) compounds [23ndash25]

is due to their versatile applicability in the pharmaceuticalindustries Generally organosilicon compounds seem to owetheir antitumour properties to the immune-defensive systemof the organism The medical applications and effectivenessof the silatranes in the treatment of wounds and tumoursare thought to be related to the role of silicon in the growthof epithelial and connective tissues and hair where theirfunction is to impart strength elasticity and impermeabilityto water [26]

In view of this the synthesis of organosilicon(IV) com-plexes of Schiff bases derived from the condensation ofchloroisatin and isatin with different amino acids derivativesis reported hereinThe characterization of the complexes wasrealised by elemental analysis and spectroscopic (UV IR 1H13C and 29Si NMR) studiesTheir antibacterial activities werescreened against various bacteria

2 Experiment

Adequate care was taken to keep the organosilicon(IV) com-plexes chemicals and glass apparatus free from moisture

2 Bioinorganic Chemistry and Applications

Table 1 Analytical and physical data of the Me3Si(IV) complexes

C no Products and colour MP∘C

Yield()

Elemental analysis Found (Calcd) Mol WtFound (Calcd) Si C H N S

Me3SiL1 C13H16N2O3Si

reddish 104 6955 1001(1016)

5645(5650)

582(584)

1019(1014) mdash 27065

(27636)


reddish 138 6536 950(967)

5784(5790)

627(625)

960(965) mdash 28198

(29039)

Me3SiL3 C16H22N2O3SSi

reddish 116 6980 815(801)

5475(5483)

630(633)

792(799)

901(915)

35612(35051)

1198721198903119878119894L4 C20H22N2O3Si

reddish 82 7959 756(766)

6563(6555)

602(605)

765(764) mdash 35783

(36649)


brown 160 7343 685(693)

6502(6516)

569(572)

1030(1036) mdash 41311

(40552)


brown 132 9030 793(788)

5719(5728)

560(566)

1575(1572) mdash 35094

(35645)

Me3SiL7 C16H21ClN2O3SSi

reddish 122 5609 718(730)

4983(4992)

545(550)

721(728)

830(833)

38032(38495)

Me3SiL8 C17H19ClN4O3Si

brown 130 7665 706(718)

5233(5223)

488(490)

1423(1433) mdash 38356

(39090)

clean and well-dried glass apparatus fitted with quickfitinterchangeable standard ground joints was used throughoutthe experimental work All the chemicals and solvents usedwere dried and purified by standard methods The ligandswere prepared by the condensation of isatins with aminoacids as described earlier [27 28]

21 Physical Measurements and Analytical Methods Siliconwas determined gravimetrically as SiO

2 Nitrogen and sul-

phur were estimated by Kjeldahlrsquos and Mesengerrsquos methodsrespectively Molecular weights were determined by the Rastcamphor method (freezing point depression method) usingresublimed camphor (MP 178∘C)The conductance measure-ments were carried out in dry dimethylformamide (DMF)at room temperature using a systronics conductivity bridge(model 305) in conjunction with a cell having a cell constantof 10 The electronic spectra were recorded on a ThermoUV1 visible spectrophotometer in the range 200ndash800 nmusing dry methanol as the solvent Infrared spectra wererecorded on a Perkin Elmer FT-IR SP-2 spectrophotometerin KBr pellets Multinuclear magnetic resonance spectrawere recorded on BRUKER AVANCE II FTNMR 400MHzspectrometer 1H NMR spectra were recorded in deuterateddimethylsulphoxide (DMSO-d

6) at 400MHz using tetram-

ethylsilane (TMS) as an internal standard 13C and 29Si NMRspectra were recorded in dry dimethylsulphoxide using TMSas the internal standard

22 Synthesis of the Organosilicon(IV) Complexes The com-plexes were prepared under anhydrous conditions by theslow addition of a dry hot methanol solution of theethoxytrimethylsilane (047 g 3385mmole) in a 1 1 molarratio to a solution of the Schiff bases (0691ndash1127 g3385mmole) in dry methanol (60mL) The mixture wasrefluxed with constant stirring giving a clear solution inhalf an hour refluxing was then continued for 10ndash12 hr

Excess solvent was removed under reduced pressure and thecompound was finally dried in vacuum at a bath temperatureof 40 plusmn 5∘C on rotary evaporator after being repeatedlywashed with a mixture of methanol and n-hexane (1 1 vv)The crystalline solids were separated out and purified byrecrystallization from the same solvent The purity of thecompounds was checked by TLC using silica gel-G asadsorbent Their physical properties and analytical data arerecorded in Table 1

23 Antibacterial Assay Synthesized compounds werescreened for their antibacterial activity against Bacilluscereus Nocardia spp E aerogenes Escherichia coli Klebsiellaspp and Staphylococcus spp at the concentrations of100 120583gmL by the agar well-diffusion method [29] Analiquot (5mL) of nutrient broth was inoculated with thetest organisms and incubated at 37∘C for 24 h Sterilenutrient agar plates were also prepared and holes of 6mmdiameter were cut using a sterile cork borer ensuring properdistribution The test organisms after 24 h of incubationwere spread onto separate agar plates The compounds weredissolved in DMSO and were poured into appropriatelylabeled holes using a pipette in aseptic conditions DMSOserved as control with Streptomycin (100 120583gmL) used asa standard antibiotic whole determination was made intriplicate for each of the compounds An average of threeindependent readings for each compound was recorded Thezone of inhibition was calculated in millimeters carefully

3 Results and Discussion

The 1 1 molar reactions of Me3Si (OC

2H5) with Schiff base

of amino acids have led to the formation of Me3Si(L) type

of complexes The reactions have been carried out in drymethanolic medium These reactions can be represented by

Bioinorganic Chemistry and Applications 3

(CH3)3SiOCH2CH3 N OHDry methanol

10ndash12 h+ +(CH3)3Si(N O) CH3CH2OH

where N OH represents the donor system of the Schiff bases

Scheme 1 Representative equation illustrating the formation of Me3Si(L) complexes

the general equations in Scheme 1 showing the formation ofthe complexes

All the newly synthesized organosilicon(IV) complexeswere coloured solids soluble in DMSO DMF and methanolThe compounds were dissolved in DMF and molar conduc-tance 10minus3M of solution at 45∘C was measured The molarconductance valves of the complexes fall in the range 08ndash16 ohmminus1 cm2molminus1 indicating that these compounds arenonelectrolytic nature The analytical data were in the goodagreement with the proposed stoichiometry of the complexes(Table 1)

31 Electronic Spectra The electronic spectra of the Schiffbase and its 1 1 organosilicon(IV) complexes have beenrecorded in methanol (Figure 1) Complexes exhibit twobands in the regions 205ndash220 and 250ndash260 nm which maybe due to the 120587ndash120587lowast transition of benzenoid120587ndash120587lowast transitionof COO chromophore respectivelyThe spectra of the ligandshow a weak broad absorption band at sim340 nm whichcan be assigned to the 119899-120587lowast transitions of the azomethinegroup This band shows a blue shift in the silicon complexesappearing at sim332 nm due to the polarisation within thegtC=Nminus chromophore caused due to formation of covalentsilicon-nitrogen bond The bands at sim260 and sim282 nmare due to 120587ndash120587lowast transitions within the benzene ring and(gtC=Nminus) band of the azomethine group respectively The Kband120587ndash120587lowast showed a red shift due to the overlap of the centralsilicon d-orbital with the p-orbital of the donor atom whichcauses an increase in conjugation and the B-bands undergoa hypsochromic shift in the complexes

32 IR Spectra The characteristic infrared absorption fre-quencies (in cmminus1) and their assignments for the ligands andtheir organosilicon(IV) complexes are given in Table 2 Theassignments of characteristic IR frequencies for the resultingcomplexes may be discussed as follows The IR spectra ofthese derivatives do not show any band in the region 3110ndash2740 cmminus1 which could be assigned to ](COOH)This clearlyindicates the deprotonation of the ligand as a result of com-plexationwith the silicon atom [28] It is further confirmed bythe appearance of sharp band at 520ndash535 cmminus1 in the spectraof all the complexes assignable to the ](SindashO) stretchingvibrations [30] In the spectra of the complexes two sharpbands are observed at 1604 and 1320 cmminus1 and are assignedto the ]asym(COO) and ]sym(COO) respectively Further-more the separation between asymmetric and symmetricvibrations is about 271 plusmn 5 cmminus1 indicating the covalentnature of the silicon-oxygen bond Ionic bonding and alsobridgingchelation can therefore be excluded and it must be

0

05

1

15

Abs

300 400 500 600Wavelength (nm)

L6H

Me3Si(L6)

Figure 1 Electronic Spectra of Ligand (L6H) and their SiliconComplex

assumed that the carboxylic group binds silicon unidentallyMoreover Δ] values of complexes below 200 cmminus1 would beexpected for bridging or chelating carboxylates but greaterthan 200 cmminus1 for the monodentate bonding carboxylateanions [31 32] The C=O band of the indole group appearsin the range of 1720ndash1735 cmminus1 in the ligands However astrong band at sim1730 cmminus1 due to the vibration of C=O groupremains unchanged in the spectra of complexes showingthereby the noninvolvement of this group in coordinationthus confirms that the C=O from indole is not involved inthe complexation

The sharp and strong band at 1628 plusmn 7 cmminus1 due to](gtC=Nminus) frequency of the free azomethine group in theligand shifts to the lower frequency (10ndash15 cmminus1) in thespectra of the silicon complexes indicating coordinationthrough the azomethine nitrogen to the silicon atom Theshift can be explained by a reduction of the carbon-nitrogendouble bond character in the azomethine group [33 34]Formation of a silicon nitrogen bond was further confirmedby the presence of a new band at 570ndash550 cmminus1 of ](SilarrN)[35] A characteristic band at 3250 cmminus1 due to ](NndashH) ofindole was observed in the spectra of the ligand and theirsilicon complexes Several new bands of strong to medium


Table 2 Important IR spectral data (cmminus1) of Schiff bases and their corresponding organosilicon(IV) complexes

Compounds ] (OH) ] (C=Nndash) ] (C=O) ] (COO)asym ] (COO)sym Δ] ] (SilarrN) ] (SindashO)L1H 3090ndash2750 br 1625 s 1720 s mdash mdash mdash mdash mdashMe3SiL

1 mdash 1610 m 1722 m 1588 vs 1322 m 266 570 m 425 mL2H 3105ndash2790 br 1635 s 1730 s mdash mdash mdash mdash mdashMe3SiL

2 mdash 1622 s 1729 s 1595 vs 1320 s 275 550 w 430 mL3H 3090ndash2750 br 1625 s 1720 s mdash mdash mdash mdash mdashMe3SiL

3 mdash 1614 s 1720 s 1604 s 1332 s 272 555 s 420 wL4H 3090ndash2740 br 1620 s 1728 mMe3SiL

4 1608 m 1726 m 1590 s 1318 m 272 550 m 428 mL5H 3108ndash2795 br 1630 s 1725 s mdash mdash mdash mdash mdashMe3SiL

5 mdash 1615 s 1724 s 1594 s 1324 s 270 568 m 429 sL6H 3090ndash2740 br 1620 s 1728 s mdash mdash mdash mdash mdashMe3SiL

6 mdash 1609 s 1730 s 1600 s 1324 m 276 558 m 427 wL7H 3110ndash2750 br 1622 s 1735 s mdash mdash mdash mdash mdashMe3SiL

7 mdash 1611 s 1732 s 1597 vs 1322 s 275 560 w 425 wL8H 3100ndash2740 br 1625 s 1730 m mdash mdash mdash mdash mdashMe3SiL

8 mdash 1610 m 1732 s 1592 s 1320 m 272 565 m 435 mbr broad vs very sharp v sharp m medium and w weak

intensity in the spectra of the complexes at 1272plusmn5 and 760 plusmn5 cmminus1 may be due to the asymmetric deformation modeof SindashCH

3and stretching vibrations of SindashC respectively

[36 37]

33 1H NMR Spectra The 1H NMR spectral data of theligands and their silicon complexes have been recorded inDMSO-d

6 The chemical shift values relative to the TMS

peak are listed in Table 3 The 1H NMR spectral data ofthe ligands show single resonance at 120575 1125ndash1255 ppmwhich is absent in the spectra of the silicon complexesindicating the replacement of the carboxylic protons by theSi(IV) moiety The ligand shows a complex pattern in theregion 120575 810ndash692 ppm for the aromatic protons and this isobserved in the region 120575 795ndash710 ppm in the spectra of theorganosilicon(IV) complexes This shifting also supports thecoordination through the nitrogen atom The appearance ofsignals due to NH protons at the same positions in the ligandand its complexes shows the noninvolvement of this groupin coordination Schiff bases derived from glycine alaninevaline and methionine display fourthree aromatic protonsas expected In the spectrum of phenylalanine the integral ofthe aromatic region corresponds to nine protons five protonson the phenyl ring are recognizable at 74 ppm Methylene(for glycine alanine valine and methionine) protons on the120572-carbon of the carboxylic acid moieties appear at 120575 396ndash430 ppmThis signal is a singlet for (1) a doublet for (3) and(6) a triplet for (7) and (8) and a quartet for (2) and (5)all of which arise from the nonequivalent methylene protonsin structures (1ndash8) In general the complexes obtained werefound to exhibit no additional resonances and thus reflectthe purity of the complexesThe integration of peaks concurswith the number of protons postulated from the structuresproposed for the complexes The additional signal in the

region 120575 (132minus120 ppm) in Me3Si(L) complexes is due to

Me3Si group

34 13C NMR Spectra The 13C-NMR spectral data alongwith assignment of characteristic signals of ligands and itsorganosilicon(IV) complexes are presented in Table 4 Thesignals due to the carbon atoms attached to the carboxylateand the azomethine groups in ligands appear at 120575 1761ndash1785 ppm and 120575 1558ndash1636 ppm respectively However inthe spectra of the corresponding silicon complexes theseappear at 120575 1807ndash1861 ppm (carboxylate group) and at120575 1502ndash1527 ppm (azomethine group) respectively Theconsiderable shifts in the positions of these signals clearlyindicate the involvement of these functional groups in bondformationwith the silicon atomThe carbon ofmethyl groups(SindashCH

3) is observed at position comparable to other similar

compounds The occurrence of resonances in the range of120575 1183ndash1507 ppm in the 13C-NMR spectra of the complexesand ligand was defined as aromatic carbon signals

Although it is also possible that the shifting of theazomethine carbon signal and carboxylate carbon signal isbecause of a change in hybridization of the nitrogen andoxygen attached to the group in the light of IR UV and 1HNMR spectral studies it seemsmore plausible that the shiftingin these carbons is due to the involvement of carboxylateoxygen and azomethine nitrogen in bonding

35 29Si NMR Spectra In order to confirm the geometryof the complexes 29Si NMR spectra of the complexes wererecorded (Figure 2)The value of 120575 29Si in the spectra reflectsthe coordination number of the nucleus in the correspondingsilicon complexes [38 39] In general 29Si chemical shiftmoves to lower frequency with increasing coordination


Table 3 1H NMR spectral dataa of the ligands and their corresponding Me3Si(IV) complexes

Compounds Chemical Shift (120575 ppm)

L1H 1128 (s 1H COOH) 430 (s 2H NndashCH2ndash) 802 (s 1H NH) H-aromatic 758 (d 119869 = 78 1H) 728ndash748 (m 2H) and780 (d 119869 = 77 1H)

Me3SiL1 432 (s 2H NndashCH2ndash) 803 (s 1H NH) H-aromatic 772 (d 119869 = 76 1H) 722ndash752 (m 2H) 798 (d 119869 = 73 1H) and

132 (s 9H SindashCH3)

L2H 1125 (s 1H COOH) 472 (q 1H CH) 834 (s 1H sec amide) 131 (d 119869 = 68 3H CH3) H-aromatic 761 (d 119869 = 761H) 721ndash741 (m 2H) and 782 (d 119869 = 74 1H)

Me3SiL2 470 (q 1H CH) 836 (s 1H sec amide) 128 (d 3H CH3) H-aromatic 766 (d 119869 = 77 1H) 720ndash746 (m 2H) 798 (d

119869 = 76 1H) and 125 (s 9H SindashCH3)

L3H 1174 (s 1H COOH) 472 (d 119869 = 68 1H CH) 805 (s 1H sec amide) 230 (m 2H CH2) 204 (d 119869 = 64 3H CH3)H-aromatic 758 (d 119869 = 81 1H) 718ndash738 (m 2H) and 772 (d 119869 = 76 1H)

Me3SiL3 450 (d 1H CH) 801 (s 1H sec amide) 222 (m 2H CH2) 206 (d 3H CH3) H-aromatic 764 (d 119869 = 79 1H)

716ndash746 (m 2H) 788 (d 119869 = 75 1H) and 126 (s 9H SindashCH3)

L4H 1150 (s 1H COOH) 425 (t 1H NndashCHndashCH2ndash) 308 (d 119869 = 68 2H ndashCH2ndashPh) 801 (s 1H NH) ) H-aromatic 762 (d119869 = 81 1H) 720ndash745 (m 2H) and 780 (d 119869 = 78 1H)

Me3SiL4 426 (t 1H NndashCHndashCH2ndash) 312 (d 119869 = 69 2H ndashCH2ndashPh) 808 (s 1H NH) H-aromatic 770 (d 119869 = 79 1H) 720ndash745

(m 2H) 798 (d 119869 = 78 1H) and 130 (s 9H SindashCH3)

L5H 1146 (s 1H COOH) 439 (d 119869 = 83 1H CH) 812 (s 1H sec amide) 1015 (s 1H indole) 302 (m 2H CH2)H-aromatic 765 (d 119869 = 78 1H) 715ndash730 (m 2H) and 784 (d 119869 = 76 1H)

Me3SiL5 316 (d 1H CH) 807 (s 1H sec amide) 1018 (s 1H indole) 298 (m 2H CH2) H-aromatic 764 (d 119869 = 77 1H)


L6H 1255 (s 1H COOH) 461 (d 119869 = 72 1H CH) 810 (s 1H sec amide) 1292 (s 1H imidazole) 315 (m 2H CH2)H-aromatic 760 (d 119869 = 79 1H) 708ndash738 (m 2H) and 780 (d 119869 = 77 1H)

Me3SiL6 398 (d 1H CH) 803 (s 1H sec amide) 1279 (s 1H imidazole) 310 (m 2H CH2) 762 (d 119869 = 78 1H) 710ndash744 (m

2H) 794 (d 119869 = 77 1H) and 128 (s 9H SindashCH3)


Me3SiL7 486 (d 119869 = 69 1H CH) 310 (m 1H CH) 810 (s 1H sec amide) 225 (m 2H CH2) 202 (d 119869 = 63 3H CH3)

H-aromatic 766 (d 119869 = 77 1H) 712ndash748 (m 2H) 795 (d 119869 = 79 1H) and 120 (s 9H SindashCH3)

L8H 1228 (s 1H COOH) 445 (t 1H ndashCHndash) 328 (d 119869 = 65 2H CH2) H-aromatic 760 (d 119869 = 78 1H) 712ndash738 (m 2H)and 782 (d 119869 = 77 1H)

Me3SiL8 440 (t 1H ndashCHndash) 325 (d 119869 = 66 H CH2) H-aromatic 765 (d 119869 = 78 1H) 714ndash750 (m 2H) 792 (d 119869 = 78 1H)

and 127 (s 9H SindashCH3)aChemical shift (120575) in ppm multiplicity is given as s singlet d doublet t triplet q quartet and m complex pattern

Table 4 13C NMR spectral data of the ligands and their corresponding organosilicon(IV) complexes

Compounds Chemical shift in (120575 ppm)COOH CH C=N SindashCH3 Aromatic carbons

L1H 1761 524 1636 mdash 1485 1310 1298 1253 1229 1191Me3SiL

1 1854 533 1524 1410 1453 1312 1295 1251 1226 1202L2H 1726 635 1558 mdash 1599 1304 1295 1338 1109 1485 1213Me3SiL

2 1807 642 1502 1367 1554 1306 1292 1340 1115 1481 1210L3H 1782 604 1629 mdash 1573 1446 1361 1323 1284 1225 1168Me3SiL

3 1861 601 1526 1390 1559 1449 1359 1323 1291 1223 1172L4H 1768 678 1634 mdash 1492 1358 1330 1286 1275 1263 1246 1229 1201Me3SiL

4 1848 666 1513 1390 1467 1359 1332 1273 1270 1265 1248 1223 1204

L5H 1774 726 1624 mdash 1602 1507 13811315 1304 1282 1245 124112381226 1212 1206 1174 1122 1094

Me3SiL5 1847 723 1527 1398 1581 1496 1380 1317 1301 1287 1248 1244 1234

1223 1216 1201 1188 1129 1103


Table 5 Antibacterial activity of ligands and their organosilicon(IV) complexes

CompoundsInhibition zone (mm) and activity index (AI)a

Bacillus cereus Nocardia spp Staphylococcus spp E coli Klebsiella spp E aerogenes100120583gmL 100 120583gmL 100 120583gmL 100 120583gmL 100 120583gmL 100 120583gmL

L1H 56 (0394) 59 (0450) 67 (0453) Inact Inact InactMe3SiL

1 78 (0549) 84 (0641) 82 (0554) 36 (0283) 28 (0250) 35 (0280)L2H 66 (0465) 72 (0550) 79 (0534) Inact Inact InactMe3SiL

2 105 (0739) 119 (0908) 98 (0662) 39 (0307) 32 (0286) 35 (0280)L3H 96 (0394) 99 (0556) 94 (0635) 67 (0528) 54 (0482) 62 (0496)Me3SiL

3 126 (0887) 127 (0969) 129 (0871) 95 (0748) 99 (0884) 87 (0696)L4H 85 (0599) 81 (0618) 87 (0587) 62 (0488) 74 (0661) 71 (0568)Me3SiL

4 106 (0745) 124 (0947) 121 (0818) 98 (0772) 95 (0848) 108 (0864)Streptomycin 142 131 148 127 112 125a(AI) inhibition zone of test compoundsinhibition zone of standard

300 200 100 0 minus100 minus200 minus300 minus400(ppm)

minus95

72

Figure 2 29Si NMR spectrum of Me3Si(L2)

number of the nuclei The spectra show in each case onlyone sharp singlet indicating the formation of a single speciesIn the 29Si NMR spectra of the silicon complexes a sharpsignal appears in the range ofminus968 tominus909 ppmwith respectto TMS indicating a penta-coordinated environment aroundthe silicon atomwith the nitrogen atom occupying equatorialposition and the most electronegative atom occupying axialposition On the basis of the spectroscopic studies the penta-coordinated structure of the complexes shown in Figure 3 hasbeen proposed

36 Antimicrobial Activities In vitro antibactericidal activityof the ligands (HL1minus4) silicon complexes and standarddrugs was screened separately for their antibacterial activity

against Gram-positive and Gram-negative bacteria (Bacilluscereus Nocardia spp E aerogenes Escherichia coli Klebsiellaspp and Staphylococcus spp) Streptomycin was used as areference compound for antibacterial activities These bac-terial strains are used because they are known as commonpathogens of human beings The antimicrobial studies sug-gested that the Schiff bases are biologically active and theirsilicon complexes showed significantly enhanced antibacte-rial activity against microbial strains in comparison to thefree ligands Tested compounds showed zone of inhibitionranging 56mmndash129mm against the Gram-positive bacteriaand between 28mmndash108mm against Gram-negative bac-teria The ligands ( HL1minus4) show zone of inhibition ranging56mmndash99mmagainst Gram-positive bacteria and 28mmndash74mm against Gram-negative bacteria It has been observedthat the silicon complexes showed increased zone of inhi-bition against the bacterial strains (Table 5) as comparedto ligands On the basis of zone of inhibition producedagainst the test bacterium compound 3 was found to bemosteffective against Bacillus cereus Nocardia spp Staphylococcusspp E coli Klebsiella spp and E aerogenes with zone ofinhibition of 126mm 127mm 129mm 95mm 99mmand 87mm respectively (Table 5) This also showed that theantibacterial activity of ligands is greatly enhanced when it iscoordinated to silicon ions

Although it is difficult to make out an exact structure-activity relationship between the antimicrobial activity andthe structure of these complexes it can possibly be concludedthat the biological activity of the ligands exhibited a markedenhancement on coordination with the silicon ions againstall the test bacterial strains which shows that silicon chelatesare more active than the ligands This may be explained byTweedyrsquos chelation theory [40 41] according to which chela-tion reduces the polarity of the central metal atom becauseof the partial sharing of its positive charge with the ligandwhich favours permeation of the complexes through the lipidlayer of cell membrane [42] According to the Overtonersquosconcept of cell permeability the lipidmembrane surroundingthe cell favors the passage of only lipid-soluble materialstherefore liposolubility is an important factor which controlsthe antimicrobial activity [43] On chelation polarity of the


N

O

Si

R

R

O

O

H H H

H

H

H

N

NH

CH3

CH3

CH3

CH3

NH

NH

NH

NH

R998400

R998400 R R998400

H2C

CH2

CH2

ClCl(CH2)2SCH3

(CH2)2SCH3

L1H L2H

L3H L4H

L5H L6H

L7H L8H

Abbr Abbr

Figure 3 Structure of Organosilicon(IV) Complexes

metal ion is reduced to a greater extent due the overlappingof the ligand orbital and partial sharing of the positivecharge of the silicon ion with donor groups Moreoverdelocalization of the p-electrons over the whole chelate ringis increased and lipophilicity of the complexes is enhancedThe increased lipophilicity enhances the penetration of thecomplexes into the lipid membranes and blocks the siliconbinding sites in the enzymes of microorganisms In generalsilicon complexes are more active than ligands as they mayserve as principal cytotoxic species

4 Conclusions

We report here the synthesis and the characterization ofeight new complexes of silicon with Schiff bases derivedfrom isatins and amino acids The newly synthesized Schiffbases act as bidentate ligands coordinating to silicon ionthrough azomethine nitrogen and carboxylate oxygen atomThe synthesized compounds were characterized by elementalanalysis UV-visible IR and NMR spectroscopy as wellas by conductance measurements Thus on the basis ofthe previously mentioned spectral features as well as theanalytical data the penta-coordinated trigonal bipyramidalgeometries shown in Figure 3 have been suggested for theorganosilicon(IV) complexes The Schiff bases and theirsilicon complexes were found to be highly active againstsome of the antibacterial species The activity is significantlyincreased on coordination

Acknowledgments

The authors are thankful to the Dean of Faculty of Engi-neering and Technology Mody Institute of Technology andScience Deemed University Lakshmangarh Sikar for pro-viding necessary facilities to carry out this research workThey are also thankful to Dr Tejpal Dewa Department ofMicrobiology University of Delhi for providing antimicro-bial screening facilities

References

[1] M Iqbal S Ali N Muhammad M Parvez P Langer andA Villinger ldquoSynthesis characterization crystal structures andelectrochemical studies of organotin(IV) carboxylatesrdquo Journalof Organometallic Chemistry vol 723 pp 214ndash223 2013

[2] D Karmakar M Fleck R Saha M Layek S Kumar and DBandyopadhyay ldquoSynthesis and crystal structure of a groupof phenoxo-bridged heterodinuclear [Ni119868119868Hg119868119868] Schiff basecomplexesrdquo Polyhedron vol 49 pp 93ndash99 2013

[3] A R Parent S Vedachalam C P Landee and M M TurnbullldquoSyntheses crystal structures and magnetic properties of het-eronuclear bimetallic compounds of [Cu(pdc)

2][M(H

2O)5] sdot

2H2O [M=Ni(II) Co(II) Mn(II) pdc = 26-pyridinedicarbox-

ylato]rdquo Journal of Coordination Chemistry vol 61 no 1 pp 93ndash108 2008

[4] A A Khandar V T Yilmaz F Costantino S Gumus S AHosseini-Yazdi and G Mahmoudi ldquoSyntheses studies andcrystal structures of coordination polymers and dinuclearcomplexes of mercury(II) halides and thiocyanate with a


symmetrical Schiff base ligandrdquo Inorganica Chimica Acta vol394 pp 36ndash44 2013

[5] A AzadmeherMM Amini NHadipour H R Khavasi H-KFun and C-J Chen ldquoSynthesis and structural characterizationof diorganotin(IV) complexes with 26-pyridinedicarboxylicacidrdquo Applied Organometallic Chemistry vol 22 no 1 pp 19ndash24 2008

[6] C J Dhanaraj and M S Nair ldquoSynthesis characterization andantimicrobial studies of some Schiff-base metal(II) complexesrdquoJournal of Coordination Chemistry vol 62 no 24 pp 4018ndash4028 2009

[7] L Puccetti G Fasolis D Vullo Z H Chohan A Scozzafavaand C T Supuran ldquoCarbonic anhydrase inhibitors Inhibitionof cytosolictumor-associated carbonic anhydrase isozymes III IX and XII with Schiff rsquos bases incorporating chromoneand aromatic sulfonamide moieties and their zinc complexesrdquoBioorganic and Medicinal Chemistry Letters vol 15 no 12 pp3096ndash3101 2005

[8] M N Patel C R Patel and H N Joshi ldquoSynthesis characteri-zation and biological studies of mononuclear copper(II) com-plexes with ciprofloxacin and N O donor ligandsrdquo InorganicChemistry Communications vol 27 pp 51ndash55 2013

[9] M Ul-Hassan Z H Chohan A Scozzafava and C T SupuranldquoCarbonic anhydrase inhibitors Schiff rsquos bases of aromatic andheterocyclic sulfonamides and their metal complexesrdquo Journalof Enzyme Inhibition andMedicinal Chemistry vol 19 no 3 pp263ndash267 2004

[10] H-Y Zhang J Lei Y-Y Chen Q-A Wu Y-S Zhang andL-H Gao ldquoSynthesis of the N1198731015840-bis(ferrocenylmethylene)-12-phenylenediamine schiff base and six rare earth metalcomplexesrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 31 no 6 pp 973ndash981 2001

[11] J Zuo C Bi Y Fan et al ldquoCellular and computational studiesof proteasome inhibition and apoptosis induction in humancancer cells by amino acid Schiff base-copper complexesrdquoJournal of Inorganic Biochemistry vol 118 pp 83ndash93 2013

[12] H L Singh J B Singh and K P Sharma ldquoSynthetic struc-tural and antimicrobial studies of organotin(IV) complexesof semicarbazone thiosemicarbazone derived from 4-hydroxy-3-methoxybenzaldehyderdquo Research on Chemical Intermediatesvol 38 no 1 pp 53ndash65 2012

[13] M SharmaH L Singh SVarshney P Sharma andAKVarsh-ney ldquoSome new coordination compounds of organosilicon(IV)with schiff bases of sulpha drugsrdquoPhosphorus Sulfur and Siliconand the Related Elements vol 178 no 4 pp 811ndash819 2003

[14] K Singh D Dharampal and V Parkash ldquoSynthesis spectro-scopic studies and in vitro antifungal activity of organosili-con(IV) and organotin(IV) complexes of 4-amino-5-mercapto-3-methyl-S-triazole Schiff basesrdquo Phosphorus Sulfur and Siliconand the Related Elements vol 183 no 11 pp 2784ndash2794 2008

[15] A Doddi J V Kingston V Ramkumar M Suzuki MHojo and M N S Rao ldquoSynthesis and characterizationof dianionic hexacoordinate silicon(iv) complexes of substi-tuted catechols flavones and fluorone X-ray crystal struc-tures of [(n-C

3H7)2NH2]2[(Cl4C6O2)3Si] sdot 3 CH

3CN and [(n-

C3H7)2NH2]2[(Br4C6O2)3Si] sdot 2 (CH

3)2SOrdquo Phosphorus Sulfur

and Silicon and the Related Elements vol 187 no 3 pp 343ndash3562012

[16] G Eng D Whalen P Musingarimi J Tierney and M DeRosaldquoFungicidal and spectral studies of some triphenyltin com-poundsrdquo Applied Organometallic Chemistry vol 12 no 1 pp25ndash30 1998

[17] Z Moradi-Shoeili D M Boghaei M Amini M Bagherzadehand B Notash ldquoNew molybdenum(VI) complex with ONS-donor thiosemicarbazone ligand preparation structural char-acterization and catalytic applications in olefin epoxidationrdquoInorganic Chemistry Communications vol 27 pp 26ndash30 2013

[18] M M Tamizh B F T Cooper C L B Macdonald and RKarvembu ldquoPalladium(II) complexes with salicylideneiminebased tridentate ligand and triphenylphosphine synthesisstructure and catalytic activity in Suzuki-Miyaura cross cou-pling reactionsrdquo Inorganica Chimica Acta vol 394 pp 391ndash4002013

[19] J Devii N Batra and S Kumar ldquoSynthesis and characteri-zation of novel Organosilicon (IV) complexes with pyridinedicarboxylic acid and Mercapto pyridine carboxylic acidrdquoInternational Journal of Research in Chemistry and Environmentvol 1 no 2 pp 50ndash56 2011

[20] M Nath S Goyal and S Goyal ldquoSynthesis spectral andbiological studies of organosilicon(IV) complexes of Schiffbases derived from amino acidsrdquo Synthesis and Reactivity inInorganic and Metal-Organic Chemistry vol 30 no 9 pp 1791ndash1804 2000

[21] R Malhotra M S Malik J P Singh and K S DhindsaldquoSynthesis characterization and microbiocidal activity of 120572-methyl-(2-thiophenomethylene) aryloxyacetic acid hydrazidesand their metal complexesrdquo Journal of Inorganic Biochemistryvol 45 no 4 pp 269ndash275 1992

[22] T M Aminabhavi N S Biradar S B Patil D E Hoffman andV N Biradar ldquoSynthesis and characterization of biologicallyactive organosilicon and organotin complexes of phenylglycylhydrazonesrdquo Inorganica Chimica Acta vol 135 no 2 pp 139ndash143 1987

[23] S Sonika M Meenakshi and R Malhotra ldquoNovel bioactivethio- and semicarbazide ligands and their organosilicon (IV)complexesrdquo Phosphorus Sulfur and Silicon and the RelatedElements vol 185 no 9 pp 1875ndash1885 2010

[24] M Jain and R V Singh ldquoSynthesis characterization andbiotoxicity of

NN donor sulphonamide imine silicon(IV) com-plexesrdquo Bioinorganic Chemistry and Applications vol 2006Article ID 13743 10 pages 2006

[25] M Nath and S Goyal ldquoSynthesis characteristic spectral stud-ies and in vitro antimicrobial activity of organosilicon(IV)derivatives of N-benzoylamino acidsrdquo Synthesis and Reactivityin Inorganic andMetal-Organic Chemistry vol 34 no 1 pp 187ndash210 2004

[26] M G Voronkov and V P Baryshok Silatranes for Medicine andAgriculture Siberian Branch of Russian Academy of SciencesNovosibirsk Russia 2005

[27] H L Singh and J B Singh ldquoSynthesis and characterizationof new lead(II) complexes of Schiff bases derived from aminoacidsrdquo Research on Chemical Intermediates vol 39 pp 1997ndash2009 2013

[28] H L Singh and J B Singh ldquoSynthesis spectroscopic andantimicrobial studies of lead(II) complexes of Schiff basesderived from amino acids and isatinsrdquo Spectroscopy Letters vol46 pp 286ndash296 2013

[29] H L Singh and J B Singh ldquoSynthesis spectral 3D molecularmodeling and antibacterial studies of dibutyltin (IV) Schiff basecomplexes derived from substituted isatin and amino acidsrdquoNatural Science vol 4 no 3 pp 170ndash178 2012

[30] M Jain S Gaur V P Singh andRV Singh ldquoOrganosilicon(IV)and organotin(IV) complexes as biocides and nematicides


synthetic spectroscopic and biological studies of NcapN donorsulfonamide imine and its chelatesrdquo Applied OrganometallicChemistry vol 18 no 2 pp 73ndash82 2004

[31] M Nath and S Goyal ldquoTriorganosilicon(IV) derivatives ofaminoacidsrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 32 no 7 p 1205 2002

[32] M Jain S Gaur S C Diwedi S C Joshi R V Singh and ABansal ldquoNematicidal insecticidal antifertility antifungal andantibacterial activities of salicylanilide sulphathiazole and itsmanganese silicon and tin complexesrdquo Phosphorus Sulfur andSilicon and the Related Elements vol 179 no 8 pp 1517ndash15372004

[33] X Zhang W H Li H Z Jia S F Weng and J G WuProceedings of the Twelfth International Conference on FourierTransform Spectroscopy Waseda University Tokyo Japan 1999

[34] M S Singh and P K Singh ldquoHexa-coordinate silicon com-plexes syntheis and chacterizationrdquo Synthesis and Reactivity inInorganic and Metal-Organic Chemistry vol 33 no 2 p 2712003

[35] M D Raju ldquoNitrogen oxygen bonded hetrocyclic organosili-con(IV) derivatives of a new Schiff base synthesis and spectralaspectsrdquo Journal of Current Chemical amp Pharmaceutical Sci-ences vol 1 no 1 pp 9ndash14 2011

[36] R Malhotra J Mehta and J K Puri ldquoHeterobimetallic com-plexes containing iron (II) and hexa-coordinated organosili-conrdquo Central European Journal of Chemistry vol 5 no 3 pp858ndash867 2007

[37] M Sharma B Khungar S Varshney H L Singh U DTripaathi and A K Varshney ldquoCoordination behavior of bio-logically active schiff bases of amino acids towards silicon(IV)ionrdquo Phosphorus Sulfur and Silicon and Related Elements vol174 pp 239ndash246 2001

[38] J H Small K J Shea D A Loy andGM JamisonACS Sympo-sium Series 585 American Chemical Society Washington DCUSA 1995

[39] K Singh P Puri and D Dharampal ldquoSynthesis and spectro-scopic studies of some new organometallic chelates derivedfrom bidentate ligandsrdquo Turkish Journal of Chemistry vol 34no 4 pp 499ndash507 2010

[40] G Tweedy ldquoPossible mechanism for reduction of elementalsulfur by monilinia fructicolardquo Phytopathology vol 55 pp 910ndash914 1964

[41] B Geeta K Shravankumar P M Reddy et al ldquoBinuclearcobalt(II) nickel(II) copper(II) and palladium(II) complexesof a new Schiff-base as ligand synthesis structural character-ization and antibacterial activityrdquo Spectrochimica Acta Part Avol 77 no 4 pp 911ndash915 2010

[42] A W Varnes R B Dodson and E L Wehry ldquoInteractions oftransition-metal ions with photoexcited states of flavins Fluo-rescence quenching studiesrdquo Journal of the American ChemicalSociety vol 94 no 3 pp 946ndash950 1972

[43] E Abele ldquoActivation of silicon bonds by fluoride ion in theorganic synthesis in the newmillennium a reviewrdquoMainGroupMetal Chemistry vol 28 no 2 pp 45ndash69 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


Table 1 Analytical and physical data of the Me3Si(IV) complexes

C no Products and colour MP∘C

Yield()

Elemental analysis Found (Calcd) Mol WtFound (Calcd) Si C H N S


reddish 104 6955 1001(1016)

5645(5650)

582(584)

1019(1014) mdash 27065

(27636)


reddish 138 6536 950(967)

5784(5790)

627(625)

960(965) mdash 28198

(29039)

Me3SiL3 C16H22N2O3SSi

reddish 116 6980 815(801)

5475(5483)

630(633)

792(799)

901(915)

35612(35051)

1198721198903119878119894L4 C20H22N2O3Si

reddish 82 7959 756(766)

6563(6555)

602(605)

765(764) mdash 35783

(36649)


brown 160 7343 685(693)

6502(6516)

569(572)

1030(1036) mdash 41311

(40552)


brown 132 9030 793(788)

5719(5728)

560(566)

1575(1572) mdash 35094

(35645)

Me3SiL7 C16H21ClN2O3SSi

reddish 122 5609 718(730)

4983(4992)

545(550)

721(728)

830(833)

38032(38495)

Me3SiL8 C17H19ClN4O3Si

brown 130 7665 706(718)

5233(5223)

488(490)

1423(1433) mdash 38356

(39090)

clean and well-dried glass apparatus fitted with quickfitinterchangeable standard ground joints was used throughoutthe experimental work All the chemicals and solvents usedwere dried and purified by standard methods The ligandswere prepared by the condensation of isatins with aminoacids as described earlier [27 28]

21 Physical Measurements and Analytical Methods Siliconwas determined gravimetrically as SiO

2 Nitrogen and sul-

phur were estimated by Kjeldahlrsquos and Mesengerrsquos methodsrespectively Molecular weights were determined by the Rastcamphor method (freezing point depression method) usingresublimed camphor (MP 178∘C)The conductance measure-ments were carried out in dry dimethylformamide (DMF)at room temperature using a systronics conductivity bridge(model 305) in conjunction with a cell having a cell constantof 10 The electronic spectra were recorded on a ThermoUV1 visible spectrophotometer in the range 200ndash800 nmusing dry methanol as the solvent Infrared spectra wererecorded on a Perkin Elmer FT-IR SP-2 spectrophotometerin KBr pellets Multinuclear magnetic resonance spectrawere recorded on BRUKER AVANCE II FTNMR 400MHzspectrometer 1H NMR spectra were recorded in deuterateddimethylsulphoxide (DMSO-d

6) at 400MHz using tetram-

ethylsilane (TMS) as an internal standard 13C and 29Si NMRspectra were recorded in dry dimethylsulphoxide using TMSas the internal standard

22 Synthesis of the Organosilicon(IV) Complexes The com-plexes were prepared under anhydrous conditions by theslow addition of a dry hot methanol solution of theethoxytrimethylsilane (047 g 3385mmole) in a 1 1 molarratio to a solution of the Schiff bases (0691ndash1127 g3385mmole) in dry methanol (60mL) The mixture wasrefluxed with constant stirring giving a clear solution inhalf an hour refluxing was then continued for 10ndash12 hr

Excess solvent was removed under reduced pressure and thecompound was finally dried in vacuum at a bath temperatureof 40 plusmn 5∘C on rotary evaporator after being repeatedlywashed with a mixture of methanol and n-hexane (1 1 vv)The crystalline solids were separated out and purified byrecrystallization from the same solvent The purity of thecompounds was checked by TLC using silica gel-G asadsorbent Their physical properties and analytical data arerecorded in Table 1

23 Antibacterial Assay Synthesized compounds werescreened for their antibacterial activity against Bacilluscereus Nocardia spp E aerogenes Escherichia coli Klebsiellaspp and Staphylococcus spp at the concentrations of100 120583gmL by the agar well-diffusion method [29] Analiquot (5mL) of nutrient broth was inoculated with thetest organisms and incubated at 37∘C for 24 h Sterilenutrient agar plates were also prepared and holes of 6mmdiameter were cut using a sterile cork borer ensuring properdistribution The test organisms after 24 h of incubationwere spread onto separate agar plates The compounds weredissolved in DMSO and were poured into appropriatelylabeled holes using a pipette in aseptic conditions DMSOserved as control with Streptomycin (100 120583gmL) used asa standard antibiotic whole determination was made intriplicate for each of the compounds An average of threeindependent readings for each compound was recorded Thezone of inhibition was calculated in millimeters carefully

3 Results and Discussion

The 1 1 molar reactions of Me3Si (OC

2H5) with Schiff base

of amino acids have led to the formation of Me3Si(L) type

of complexes The reactions have been carried out in drymethanolic medium These reactions can be represented by










0

05

1

15

Abs


L6H

Me3Si(L6)

















[36 37]





Me3Si group



































L1H 1761 524 1636 mdash 1485 1310 1298 1253 1229 1191Me3SiL

1 1854 533 1524 1410 1453 1312 1295 1251 1226 1202L2H 1726 635 1558 mdash 1599 1304 1295 1338 1109 1485 1213Me3SiL

2 1807 642 1502 1367 1554 1306 1292 1340 1115 1481 1210L3H 1782 604 1629 mdash 1573 1446 1361 1323 1284 1225 1168Me3SiL

3 1861 601 1526 1390 1559 1449 1359 1323 1291 1223 1172L4H 1768 678 1634 mdash 1492 1358 1330 1286 1275 1263 1246 1229 1201Me3SiL

4 1848 666 1513 1390 1467 1359 1332 1273 1270 1265 1248 1223 1204

L5H 1774 726 1624 mdash 1602 1507 13811315 1304 1282 1245 124112381226 1212 1206 1174 1122 1094

Me3SiL5 1847 723 1527 1398 1581 1496 1380 1317 1301 1287 1248 1244 1234

1223 1216 1201 1188 1129 1103







2 105 (0739) 119 (0908) 98 (0662) 39 (0307) 32 (0286) 35 (0280)L3H 96 (0394) 99 (0556) 94 (0635) 67 (0528) 54 (0482) 62 (0496)Me3SiL

3 126 (0887) 127 (0969) 129 (0871) 95 (0748) 99 (0884) 87 (0696)L4H 85 (0599) 81 (0618) 87 (0587) 62 (0488) 74 (0661) 71 (0568)Me3SiL



minus95

72







N

O

Si

R

R

O

O

H H H

H

H

H

N

NH

CH3

CH3

CH3

CH3

NH

NH

NH

NH

R998400

R998400 R R998400

H2C

CH2

CH2

ClCl(CH2)2SCH3

(CH2)2SCH3

L1H L2H

L3H L4H

L5H L6H

L7H L8H

Abbr Abbr



4 Conclusions


Acknowledgments


References




2][M(H

2O)5] sdot


















3CN and [(n-












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










0

05

1

15

Abs


L6H

Me3Si(L6)

















[36 37]





Me3Si group



































L1H 1761 524 1636 mdash 1485 1310 1298 1253 1229 1191Me3SiL

1 1854 533 1524 1410 1453 1312 1295 1251 1226 1202L2H 1726 635 1558 mdash 1599 1304 1295 1338 1109 1485 1213Me3SiL

2 1807 642 1502 1367 1554 1306 1292 1340 1115 1481 1210L3H 1782 604 1629 mdash 1573 1446 1361 1323 1284 1225 1168Me3SiL

3 1861 601 1526 1390 1559 1449 1359 1323 1291 1223 1172L4H 1768 678 1634 mdash 1492 1358 1330 1286 1275 1263 1246 1229 1201Me3SiL

4 1848 666 1513 1390 1467 1359 1332 1273 1270 1265 1248 1223 1204

L5H 1774 726 1624 mdash 1602 1507 13811315 1304 1282 1245 124112381226 1212 1206 1174 1122 1094

Me3SiL5 1847 723 1527 1398 1581 1496 1380 1317 1301 1287 1248 1244 1234

1223 1216 1201 1188 1129 1103







2 105 (0739) 119 (0908) 98 (0662) 39 (0307) 32 (0286) 35 (0280)L3H 96 (0394) 99 (0556) 94 (0635) 67 (0528) 54 (0482) 62 (0496)Me3SiL

3 126 (0887) 127 (0969) 129 (0871) 95 (0748) 99 (0884) 87 (0696)L4H 85 (0599) 81 (0618) 87 (0587) 62 (0488) 74 (0661) 71 (0568)Me3SiL



minus95

72







N

O

Si

R

R

O

O

H H H

H

H

H

N

NH

CH3

CH3

CH3

CH3

NH

NH

NH

NH

R998400

R998400 R R998400

H2C

CH2

CH2

ClCl(CH2)2SCH3

(CH2)2SCH3

L1H L2H

L3H L4H

L5H L6H

L7H L8H

Abbr Abbr



4 Conclusions


Acknowledgments


References




2][M(H

2O)5] sdot


















3CN and [(n-












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of














[36 37]





Me3Si group



































L1H 1761 524 1636 mdash 1485 1310 1298 1253 1229 1191Me3SiL

1 1854 533 1524 1410 1453 1312 1295 1251 1226 1202L2H 1726 635 1558 mdash 1599 1304 1295 1338 1109 1485 1213Me3SiL

2 1807 642 1502 1367 1554 1306 1292 1340 1115 1481 1210L3H 1782 604 1629 mdash 1573 1446 1361 1323 1284 1225 1168Me3SiL

3 1861 601 1526 1390 1559 1449 1359 1323 1291 1223 1172L4H 1768 678 1634 mdash 1492 1358 1330 1286 1275 1263 1246 1229 1201Me3SiL

4 1848 666 1513 1390 1467 1359 1332 1273 1270 1265 1248 1223 1204

L5H 1774 726 1624 mdash 1602 1507 13811315 1304 1282 1245 124112381226 1212 1206 1174 1122 1094

Me3SiL5 1847 723 1527 1398 1581 1496 1380 1317 1301 1287 1248 1244 1234

1223 1216 1201 1188 1129 1103







2 105 (0739) 119 (0908) 98 (0662) 39 (0307) 32 (0286) 35 (0280)L3H 96 (0394) 99 (0556) 94 (0635) 67 (0528) 54 (0482) 62 (0496)Me3SiL

3 126 (0887) 127 (0969) 129 (0871) 95 (0748) 99 (0884) 87 (0696)L4H 85 (0599) 81 (0618) 87 (0587) 62 (0488) 74 (0661) 71 (0568)Me3SiL



minus95

72







N

O

Si

R

R

O

O

H H H

H

H

H

N

NH

CH3

CH3

CH3

CH3

NH

NH

NH

NH

R998400

R998400 R R998400

H2C

CH2

CH2

ClCl(CH2)2SCH3

(CH2)2SCH3

L1H L2H

L3H L4H

L5H L6H

L7H L8H

Abbr Abbr



4 Conclusions


Acknowledgments


References




2][M(H

2O)5] sdot


















3CN and [(n-












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






























L1H 1761 524 1636 mdash 1485 1310 1298 1253 1229 1191Me3SiL

1 1854 533 1524 1410 1453 1312 1295 1251 1226 1202L2H 1726 635 1558 mdash 1599 1304 1295 1338 1109 1485 1213Me3SiL

2 1807 642 1502 1367 1554 1306 1292 1340 1115 1481 1210L3H 1782 604 1629 mdash 1573 1446 1361 1323 1284 1225 1168Me3SiL

3 1861 601 1526 1390 1559 1449 1359 1323 1291 1223 1172L4H 1768 678 1634 mdash 1492 1358 1330 1286 1275 1263 1246 1229 1201Me3SiL

4 1848 666 1513 1390 1467 1359 1332 1273 1270 1265 1248 1223 1204

L5H 1774 726 1624 mdash 1602 1507 13811315 1304 1282 1245 124112381226 1212 1206 1174 1122 1094

Me3SiL5 1847 723 1527 1398 1581 1496 1380 1317 1301 1287 1248 1244 1234

1223 1216 1201 1188 1129 1103







2 105 (0739) 119 (0908) 98 (0662) 39 (0307) 32 (0286) 35 (0280)L3H 96 (0394) 99 (0556) 94 (0635) 67 (0528) 54 (0482) 62 (0496)Me3SiL

3 126 (0887) 127 (0969) 129 (0871) 95 (0748) 99 (0884) 87 (0696)L4H 85 (0599) 81 (0618) 87 (0587) 62 (0488) 74 (0661) 71 (0568)Me3SiL



minus95

72







N

O

Si

R

R

O

O

H H H

H

H

H

N

NH

CH3

CH3

CH3

CH3

NH

NH

NH

NH

R998400

R998400 R R998400

H2C

CH2

CH2

ClCl(CH2)2SCH3

(CH2)2SCH3

L1H L2H

L3H L4H

L5H L6H

L7H L8H

Abbr Abbr



4 Conclusions


Acknowledgments


References




2][M(H

2O)5] sdot


















3CN and [(n-












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







2 105 (0739) 119 (0908) 98 (0662) 39 (0307) 32 (0286) 35 (0280)L3H 96 (0394) 99 (0556) 94 (0635) 67 (0528) 54 (0482) 62 (0496)Me3SiL

3 126 (0887) 127 (0969) 129 (0871) 95 (0748) 99 (0884) 87 (0696)L4H 85 (0599) 81 (0618) 87 (0587) 62 (0488) 74 (0661) 71 (0568)Me3SiL



minus95

72







N

O

Si

R

R

O

O

H H H

H

H

H

N

NH

CH3

CH3

CH3

CH3

NH

NH

NH

NH

R998400

R998400 R R998400

H2C

CH2

CH2

ClCl(CH2)2SCH3

(CH2)2SCH3

L1H L2H

L3H L4H

L5H L6H

L7H L8H

Abbr Abbr



4 Conclusions


Acknowledgments


References




2][M(H

2O)5] sdot


















3CN and [(n-












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


N

O

Si

R

R

O

O

H H H

H

H

H

N

NH

CH3

CH3

CH3

CH3

NH

NH

NH

NH

R998400

R998400 R R998400

H2C

CH2

CH2

ClCl(CH2)2SCH3

(CH2)2SCH3

L1H L2H

L3H L4H

L5H L6H

L7H L8H

Abbr Abbr



4 Conclusions


Acknowledgments


References




2][M(H

2O)5] sdot


















3CN and [(n-












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of















3CN and [(n-












































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






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Research Article Synthesis, Spectral, and In Vitro ...downloads.hindawi.com/journals/bca/2013/425832.pdfOrganosilicon(IV) Complexes with Schiff Bases Derived from Amino Acids HarLalSingh,JangbhadurSingh,andA.Mukherjee