Research Journal of Chemical Sciences ______________________________________________ ISSN 2231-606X Vol. 4(6), 66-72, June (2014) Res. J. Chem. Sci. International Science Congress Association 66 Synthesis, Characterization and Antibacterial Activity and DNA cleavage Studies of tetra dentate Schiff bases and their Zn (II) ComplexesSreenivas V., Srikanth G., Aruna M, Vijaya Kumar P, Muralidhar Reddy P. and Ravinder V.* Department of Chemistry, Kakatiya University, Warangal, Andhra Pradesh, INDIA Department of Chemistry, Nizam College, Osmania University, Hyderabad, Andhra Pradesh, INDIA Available online at: www.isca.in, www.isca.me Received 22nd April 2014, revised 10th May 2014, accepted 16th June 2014Abstract A new series of tetra dentate Schiff base ligands are obtained from condensation of phthalaldehyde and 2-amino benzyl alcohol, 2-amino-2-methyl-1-propanol and 2-aminobenzo hydrazine respectively, L1-L3 were reacted with Zinc acetate in aqueous methanol to give Zinc complexes (4a-c). The synthesized ligands and complexes are characterized by elemental analysis, IR, H-NMR,Mass, Electronic spectra and molar conductance studies. All the complexes and ligands are examined for their anti-bacterial activitiesby cup plate method and their very low inhibitory concentration values verified by liquid dilution method. The DNA cleavage ability of the compounds was screened by agarose gel electrophoresis using calf thymus DNA(CT-DNA).The metal complexes are exhibited good anti-bacterial and DNA cleavage activities compared with their corresponding Schiff base ligands. Keywords: Schiff base ligands, Zn (II) complexes, antibacterial activity, CT-DNA. IntroductionTetra dentate Schiff base ligands have been used as chelating agents, these are playing vital role in coordination chemistry and its metal complexes are great attention for several years1-4. Various studies have shown that the azomethine group (�C=N-) in Schiff base complexes is responsible for various biological function5-9. These complexes are used as catalysts for a wide range of organic transformations such as C-H bond activation and oxidation reactions10-14 and several azomethines were reported to possess important antibacterial15-17 antifungal18,19 and antitumor20. Zinc metal can play key rolein hydrolytic enzymes, where it is chelated by donor atoms (NorO). It has been standard at the same time a significant co-factor in bioactive molecules, each structural model in protein folding that can eagerly accept the coordination numbers 4, 5 or 6 21-23. All these considerations, the aim of this work is antibacterial activity and DNA cleavage studies24 of zinc (II) complexes of the tetra dentate Schiff base ligands. Material and Methods All the chemicals like zinc (II) acetate, o-phthalaldehyde, 2-amino benzyl alcohol, 2-amino-2-methyl-1-propanol, 2-aminobenzohydrazides were purchased from Aldrich, USA. The solvents like ethanol, methanol, DMSO were distilled out and dried up by the standard procedures25. The percentage of carbon, hydrogen, nitrogenin Schiff base metal complexes are determined using a Perkin–Elmer CHNS analyzer. The conductance of the Zn (II) complexes was measured on a Digisun digital conductivity meter (model DI-909). Infrared spectra in KBr/CsI pellets were recorded with a Perkin-Elmer 283 spectrophotometer. H and 13C NMR spectra were recorded on a Jeol 200MHz FT-NMR spectrometer in DMSO-. Mass spectra were recorded on CEC-21-110B and Finnegan MAT-1210 mass spectrometers. Hot air oven, incubator, laminar airflow unit and autoclave were used in the present investigations. The analytical data of Schiff bases and their metal compounds are given in table-1. Synthesis of tetra dentate ligands (L1-L3): The Schiff base ligands25 (L1-L3) were prepared from the condensation of 1 eq. of phthaladehyde and 2 eq. of amine derivatives as shown in scheme-1. The general preparation strategy of Schiff base ligand (L1)is described briefly as follows: A mixture of various amines (2a-c) (0.01mol), sodium acetate (0.01 mol) and phthalaldehye 1 (0.005 mol) in 10 ml of aqueous methanol was refluxed for 1 hour. The reaction mixture was cooled to room temperature, the solid separated was filtered, washed with water and recrystallized from ethanol. Synthesis of Zn (II) complexes: All Zinc (II) compounds were prepared using the literature procedure26 as given below as scheme-1: A mixture of L1- L3 (0.001 mole) and zinc acetate (0.001 mole) were refluxed for 4 hours. The reaction mixture was cooled to room temperature, the solid separated was filtered, washed with water and recrystallized from dichloromethane and ether to get pure complexes and directly used for analyses and biological activity. Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(6), 66-72, June (2014) Res. J. Chem. Sci. International Science Congress Association 67 Results and Discussion The physical and analytical data of Zn (II) compounds are depicted in table-1. The Zn (II) complexes were extremely stable at room temperature, soluble in DMF and DMSO. Analytical data revealed the Zn (II) to ligand ratio is 1:2 in all the complexes. Molar conductance measurements of compounds were recorded in DMF (1x10-3 M) and values are 12.4, 15.1 and 16.3 -1cmmol. These values indicate that all the complexes are non-electrolytic nature24. Infra-red Spectral studies: In IR spectra were shown at 1677-1639cm-1 which is recognized to azomethine group28, 29. Schiff base ligands L1 and L3 exhibited characteristic bands at 3435cm-1 and 3448cm-1which corresponding to OH group24, 25. The L2ligand showed by broad band at 3444-3359 cm-1corresponding to NH vibrations24,31, another band at 1687 cmwhich is due to C=O respectively24. IR spectraof L1,L2 and L3 are presented table-2. Infrared spectra of Zn (II) complexes explained by all the functional group bands are shifted then Zn (II) ions are coordinated with donor atoms of ligands. In all the Zn (II) complexes of azomethine group was shifted towards lower side about 40-55 cm-1 32,33. In Zn (II) complexes of L1 and L3 OH bands are disappeared due to deprotonation of ligand at the time formation of complexes. Whereas Zn (II) complex of L2 ligand NH-band was shifted to lower region side which indicated that zinc metal was strongly bonded and supported to conductivity data27. In fact, those two new bands are revealed by complexes of all spectra at 507 – 529 cm-1 assignable to M-N vibration32, 33, 34 and appeared at 430 cm-1 and 423 cm-1 for M-O bonds. The band C=O is shifted to the higher region side and observed at 1696 cm-1 which indicates that carbonyl group is not participated in complex formation. The coordinated water molecules show a characteristic absorption around 850 cm 1 in the IR spectra of complexes27. The IR spectral data of [Zn (L1) (HO) 2], [Zn (L2) (OAc) 2] and [Zn (L3) (HO) 2] are presented in table-2. H –NMR and 13C- NMRSpectral studies: In the H-NMR and 13C-NMR spectral data of all the ligands25 L1 – L3 and respective Zn (II) complexes also represented in table-3. In all ligands important peaks which are involved in complex formation are CH=N and N (L2) and these peaks are slightly shifted towards down field compared to the respective ligand24, 27.In all the ligands signals CH=N protons were appeared in the range of 8.10-8.42. However, the coordination of nitrogen atom of the azomethine group to Zn (II) ion is confirmed by the appearance of signals in the range of 8.32-8.60. In the spectra of Schiff base ligandsL1 and L3 signals at 2.80 and 2.52 was appeared due to OH protons and these signals are disappearing in the Zn (II) complexes suggesting that the OH protons are deprotonated and the oxygen atoms coordinated with metal ions. In the case of Schiff base ligand L2 the signal due to aromatic NH was appeared at 4.2 and this signal wasdeshielded inthe respective Zn (II) complex indicating the participation of nitrogen in the coordination to the Zn (II) ion. In addition to these a new signal was observed in Zn (L2) complex at 2.12 which is due to acetyl group27. There is no appreciable change in the peak positions corresponding to aromatic protons. Similarly, we are observed in 13C NMR spectra of all the Zn(II) complexes variation in the peak positions each spectra, which gave lot of information regarding shifting of H=N, -O and Ar-NH peaks and suggesting that Zn(II) ions are coordinated with N and O atoms of the respective ligands. In the spectra of Zn (II) complexes, a down field shift in peak position is observed in the range of 168.40-174.02 is azomethine carbon atom. This evidence confirms that the ligands coordinate through nitrogen atoms and appreciable changes in peak positions were not observed with respect to aryl carbons and carbons adjacent to nitrogen/oxygen atom. Table-1 Physical and analytical data of Schiff bases and their metal complexes Ligand /complex, Color M.F (M.Wt.) Yield % Found (Calcd.) % C H N Zn L1= (BDMAB) lightyellow 2220(344) (72) 76.69(76.72) 5.83(5.85) 8.19(8.13) Nil L2= (BDMAZ) white 2220(401) (75) 65.81(65.99) 4.96(5.03) 20.89(20.99) Nil L3=(BDMAM) yellow 1624(276) (70) 69.55(69.58) 8.68(8.75) 10.10(10.14) Nil [Zn L1(HO)] Deep yellow 2222Zn (442) (76) 59.52(59.54) 4.98(5.00) 6.28(6.31) 14.71 (14.73) [Zn L2 (OAc)] yellow orange 2626Zn (582) (80) 53.46(53.48) 4.47(4.49) 14.36(14.39) 11.17(11.20) [Zn L3(HO)] yellow 1626Zn (374) (78) 51.12(51.14) 6.95(6.97) 7.42(7.45) 17.37(17.40) Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(6), 66-72, June (2014) Res. J. Chem. Sci. International Science Congress Association 68 Table-2 IR Spectral data of ligands and its metal complexes (cm-1) Ligand / Complex uu C=N uu C=O uu NH/ uu N - N* uu M - N uu OH uu M - O L1 1639 Nil Nil Nil 3435 Nil L2 1642 1687 3444 Nil Nil Nil L3 1677 Nil Nil Nil 3448 Nil [ZnL1 (H 2 O) 2 ] 1576 Nil Nil 529 Nil 430 [ZnL2 (OAc) 2 ] 1596 1696 3359/1167 507 Nil 331 [ZnL3 (H 2 O) 2 ] 1597 Nil Nil 511 Nil 423 Table-3 H-NMR Spectral data of ligand and its metal complexes (dd ppm) in d-DMSO Ligand/Complex 1 H-NMR Spectra 13 C-NMR spectra L1 8.31(2H,s, CH=N),6.82-7.40 (12H,m, Ar-H),4.6 (4H, s, -CH 2 -O), 2.80(2H, s, OH) 59.5(2C,O-C), 122.5,127.5,128.5,129.0, 129.3,131.2, 132.7, 134.1,149.3, (18C, Ar-C) 160.1 (2C, CH=N) L2 8.10(2H,s, CH=N), 8.0(2H, s, NH-CO), 6.61-7.94(12H, m, Ar-H), 4.2(4H, s, Ar-NH) 116.4,118.0,118.9, 128.3, 129.3,131.2, 133.0,134.1,148.4 (18C,Ar-C), 160.1 (2C, CH=N) 163.0(2C, C=O) L3 8.42(2H,s, CH=N),7.50-7.86 (4H,m, Ar-H),3.84 (4H, s, O-CH), 2.52(2H, s, OH),1.41 (12H, s, CH 3 ) 26.20,(4C,CH-C), 55.5(2C,30 C), 72.0 (2C,C-O) 129.30,131.2,140.20(6C,Ar-C), 160.90(2C,CH=N) [Zn L1(HO)2 ] 8.42 (2H, s, CH=N), 6.50-7.62 (12H, m, Ar-H), 4.66 (4H, s, -CH). 62.02(2C,O-CH), 122.91,128.42,129.62,132.06, 134.08,136.46, 147.28(18C, Ar-C) 168.40 (2C, CH=N) [Zn L2 (OAc)2 ] 8.32 (2H, s, CH=N), 8.02 (2H, s, NH- CO), 6.72-8.10 (12H, m, Ar-H), 4.9 (4H, s, Ar-NH) 2.12 (6H, OCOCH 3 ). 118.48,119.96,129.48,132.10,,136.64, 148.34(18C,Ar-C), 169.02 (2C, CH=N),164.62(2C, C=O), 23.02(2 CH 3 , OCO), 174.02(2C, OCO) [Zn L3(HO)] 8.46 (2H, s, CH=N), 7.62-8.02 (4H, m, Ar-H), 4.02 (4H, m, -CH), 1.72 (12H, s, CH) 28.7, 32.24,(4C,CH-C),58.24(2C,3 0 C), 71.56(2C,O-C), 132.41,134.48,146.82(6C,Ar-C), 170.21(2C,CH=N) Mass spectral analysis: The mass spectra of ligands25 viz. BDMAB (L1) and BDMAZ (L2) showed the (M+Na) ion peak at m/z 367.4 (30%), 424.16(15%) and BDMAM (L3) shown molecular ion M+1 peakat m/z 277(25%) respectively. This data is in good agreement with the respective molecular formulae. The mass spectra of Schiff base Zn (II) complexes viz. [Zn (L1 (HO) 2] shown molecular ion peak (M+Na)at (m/z) 465 (24%). However, the mass spectra [Zn (L2) (OAc)] and [Zn (L3) (HO)] shown (M+1)peak at (m/z) 583,375 respectively. These values are equivalent with the respective molecular weights of the Zn (II) complexes calculated and experimental valuesare supported toward elemental analysis. Structures of the complexes: On the basis of analytical and spectral data, octahedral structures (scheme-1) have been tentatively proposed for all of Schiff base Zn (II) complexes. Antibacterial activity: The Schiff-base ligands and their Zn (II) metal complexes were assessedfor their preliminary antibacterial activity against gram +ve and gram –ve bacteria35-41. The activities of the Zn metal complexes are found to be more as compared to the ligands. The enhanced in the antibacterial activity of metal chelates may be due to the effect of the metal ion in the normal cellular process. A probable mode of toxicity increase may be measured in the light of Tweedy’s chelation theory42. Therefore, the Zn (II) complexes of ligands L2 and L3 were found to be very effective than the Zn (II) complex of L1 and all the results are given in table-4. From the results, the Zn (II) complexes with L2 and L3 ligands were found to be active at lower concentrations than the existing antibiotics like Streptomycin and Ampicillin but less than the Rifampicin. DNA cleavage studies: The nucleic acid cleavage experiment was conducted by using calf thymus (CT) DNA (1 mg/ml) as a substrate and H as oxidizing agent. The cleavage ability was established by agarose gel electrophoresis. For studying cleavage capability of Transition metal complex, 1mm of corresponding metal complexes stock solution was made and used in the present study. A reaction mixture containing 30 µM of CT DNA, 50/100/150 µM of each complex and 50 µM of in 50 mM of tris-HCl buffer (pH -7.2) was prepared and incubated at rt for 60 min. The cleavage pattern was studied by electrophorizing the samples for 1 h at 50 V on 1.2% of agarose gel using TBE (tris Borate EDTA) buffer, pH-8.2. Before electrophoresis, to 7 µl of these samples and 3 µl of Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(6), 66-72, June (2014) Res. J. Chem. Sci. International Science Congress Association 69 bromophenol blue was added as loading dye and loaded on the gel. After electrophoresis, the gel was stained using 1 µg/cmethedium bromide and photographed under UV light using a gel documentation system. Scheme-1 Synthesis of Schiff bases and their metal complexesTable-4 Zones of inhibition ofSchiff-bases and Zn (II) complexes against four different bacteria Schiff bases & Zn Complexes Conc. (100mmg/ml) Zone of inhibition (mm) Basillus subtilis Staphylo coccus aureus Escherichia Coli Klebsiella Pneumonia L1 1000 13 12 Nil Nil L2 100017 14 15 16 L3 1000 16 17 18 14 [Zn L1(H 2 O) 2 ] 1000 25 23 21 24 [Zn L2(OAc) 2 ] 1000 45 43 44 38 [Zn L3(H 2 O) 2 ] 1000 41 34 41 36 Streptomycin 1000 10 126 6 Ampicillin 1000 11 13 8 7 Rifampicin 1000 51 49 48 45 Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(6), 66-72, June (2014) Res. J. Chem. Sci. International Science Congress Association 70 In the current study, the DNA cleavage of Zn (II) complexes was monitored by agarose gel electrophoresis. All the compounds have shown modest to good DNA cleavage ability. After the electrophoresis, in all the wells loaded with compound treated calf thymus (CT)-DNA, spread was found, indicating the cleavage ability of compounds. At higher concentrations, even spread or DNA band was not observed in the region of the control DNA region representing that the DNA was totally cleaved. The Schiff base ligands L1 and L2 have shown good cleavage activity except L3. The Zn (II) metal complexes exhibited noticeable cleavage activity when compared to their Schiff base ligands. In case of [Zn L1 (HO) 2] exhibited good cleavage activity compared to their [Zn L2(OAc) 2] and [Zn L3 (HO) 2]. However, from the studies, it is found to be that Zn (II) complexes are more cleavage activity. The results of DNA cleavage studies are depicted in figure-1and figure-2.This result indicates that, these transition metal complexes are having a potent DNA cleavage activity and can be used in drug preparation. Figure-1 DNA cleavage in the absence of H2, Lane 1a: DNA+L1; Lane 1b: DNA+L2; Lane 1c: DNA+L3; DNA cleavage studies of ligands having different concentration are a, b and c, here CT= Calf Thymus, Cn = Control DNA ConclusionThe Zn (II) complexes are acquired from the various Schiff base ligands and characterized by spectral and analytical data. The results shown that all ligands are coordinated in a tetra dentate fashion to the metal ion and the 5th and 6th position water molecules are coordinated. Based on the analytical and spectral data, the geometry of the complexes is found to be distorted octahedral nature. The Zn (II) complexes have higher antibacterial activity than the ligands. The CT-DNA cleavage studies explain that total cleavage of CT-DNA was observed by Zn (II) complexes. Figure-2 DNA cleavage in the Presence of H, Lane 1a: DNA + ZnL1 (HO)2 + H2 ; Lane 1b: DNA + ZnL2 (OAc)2 + H2 ; Lane 1c: DNA + ZnL3 (HO)2 + H2 ; Metal complexes having different concentration. Here a, b and c are concentrations a= 50 µM, b= 100 µM and c=150 µM and L1-3 = Schiff base ligands References 1.Hazra S., Koner R., Lemoine P., Sanudo E.C. and Mohanta S., Syntheses, Structures and Magnetic Properties of Heterobridged Dinuclear and Cubane-Type Tetranuclear Complexes of Nickel (II) Derived from a Schiff Base Ligand, Eur. J. Inorg. Chem., 23, 3458-3466 (2009) 2.Li B.Y., Yao Y.M., Wang Y.R., Zhang Y. and Shen Q.,Reduction of imine of samarium Schiff base chloride by sodium—Formation of a novel samarium complex through unprecedented C–C coupling and hydrogen transfer reaction, Inorg. Chem. Commun., 11(3), 349-352 (2008)3.Chakraborty J., Ray A., Pilet G., Luneau D, Ziessel R.F., Chabonnier L.J., Carrella L., Rentschler E., EI Fallah M.S., Mitra S., Dalton Trans., 4923 (2009) 4.Gupta Y.K., Agarwal S.C., Madnawat S.P., Narain R., Synthesis, Characterization and Antimicrobial Studies of Some Transition Metal Complexes of Schiff Bases, Res. J .Chem. Sci., ), 68-71 (2012) 5.Elemike E.E., Oviawe A.P., Otuokere I.E., Potentiation of the Antimicrobial Activity of 4-Benzylimino-2, 3- Dimethyl-1-Phenylpyrazal-5-One by Metal Chelation, Res. J .Chem. Sci.,), 6-11 (2011). 6.Vinita G., Sanchita S., Gupta Y.K., Synthesis and Antimicrobial Activity of some Salicylaldehyde Schiff bases of 2-aminopyridine, Res. J .Chem. Sci., 26-29 2013) 7.Shanker K., Rohini R., Ravinder V., Reddy P.M., Ho Y.P., Ru(II) complexes of N4 and N2O2 macrocyclic Schiff base ligands: Their antibacterial and antifungal studies, Spectrochim. Acta A, 73), 205-211 (2009) Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(6), 66-72, June (2014) Res. J. Chem. Sci. International Science Congress Association 71 8.Shanker K., Reddy P.M., Rohini R., Ho Y.P., Ravinder V., Encapsulation of Pd(II) by N4 and N2O2 macrocyclic ligands: their use in catalysis and biology, J. Coord. Chem., 6218), 3040-3049 (2009)9.Shanker K., Rohini R., Shravankumar K., Reddy P.M., Ho Y.P., and Ravinder V., Synthesis of tetraaza macrocyclic Pd-II complexes, antibacterial and catalytic studies, J. Indian Chem. Soc., 86), 153-161 (2009)10.Rayati S., Torabi N., Ghamei A., Mohebbi S., Wojtczak A., Kozakiewicz A., Vanadyl tetradentate Schiff base complexes as catalyst for C–H bond activation of olefins with tert-butylhydroperoxide: Synthesis, characterization and structure, Inorg. Chim. Acta., 361), 1239-1245 (2008)11.Edmund K., Romanowski G., Nowicki W., Kwiatkowski M., Suwiska K., Chiral dioxovanadium(V) complexes with single condensation products of 1,2-diaminocyclohexane and aromatic o-hydroxycarbonyl compounds: Synthesis, characterization, catalytic properties and structure, Polyhedron, 2612, 2559-2568 (2007) 12.Ashok M., Prasad A.V.S.S., Reddy P.M. and Ravinder V., Ru(III)-catalyzed oxidation of pyridoxine and albuterol in pharmaceuticals, Spectrochim. Acta A, 72), 204-208 2009)13.Reddy P.M., Prasad A.V.S.S., Reddy C.K. and Ravinder V., Synthesis of new macrocyclic rhodium(III) compounds and their utility as catalysts for the oxidation of ascorbic acid, Transit. Met. Chem., 33), 251-258 (2008)14.Reddy P.M., Prasad A.V.S.S. and Ravinder V., Synthesis, spectral characterization, catalytic and antibacterial activity of macrocyclic CuII compounds, Transit. Met. Chem. 32), 507-513 (2007) 15.Pachori K., Malik S., Wankhede S.,Synthesis, Characterization and Antimicrobial studies of Transition metal complexes of Co(II) and Ni(II)derived from Cefadroxil, Res. J .Chem. Sci.,4(2), 75-80, (2014) 16.Bayrak H., Demirbas A., Karaoglu S.A., Demirbas N.,Synthesis of some new 1,2,4-triazoles, their Mannich and Schiff bases and evaluation of their antimicrobial activities, Eur. J .Med. Chem., 44 , 1057-1066, (2009) 17.Reddy, P. M., Ho, Y.-P., Shanker, K., Rohini, R., Ravinder, V., Physicochemical and biological characterization of novel macrocycles derived from o-phthalaldehyde, Eur. J. Med. Chem., 44), 2621-2625,(2009)18.Rohini, R., Shanker, K., Reddy, P. M., Sekhar, V. C., Ravinder, V., 6-Substituted Indolo[1,2-c]quinazolines as New Antimicrobial Agents, Arch. Pharm., 342), 533-540,(2009)19.Rohini, R., Reddy, P. M., Shanker, K., Kanthaiah, K., Ravinder, V., Hu, A., Synthesis of mono, bis-2-(2-arylideneaminophenyl) indole azomethines as potential antimicrobial agents, Arch. Pharmacal Res., 34), 1077-1084,(2011)20.Jin V.X., Tan S.I. and Ranford J.D., Platinum (II) triammine antitumour complexes: structure–activity relationship with guanosine 5-monophosphate (5GMP),Inorg. Chim. Acta., 358, 677 -686, (2005) 21.Lipscomb W.N., Strater N.,Recent Advances in Zinc Enzymology, Chem. Rev., 96), 2375-2434, (1996) 22.Vallee B.L., Auld D.S.Zinc: biological functions and coordination motifs, Acc. Chem. Res., 2610, 543-551, 1993) 23.Sun X.X., Qi C.M., Ma S.L., Huang H.B., Zhu W.X., Liu Y.C., Syntheses and structures of two Zn(II) complexes with the pentadentate Schiff-base ligands, Inorg. Chem. Commun., , 911-914, (2006). 24.Manjula B., Arul Antony S., Arul Antony S., Studies on DNA Cleavage and Antimicrobial screening of Transition Metal complexes of 4-aminoantipyrine Schiff base, Res. J .Chem. Sci., 12 22-28, (2013). 25.Sreenivas V., Srikanth G., Vinutha Ch., Shailaja M., Muralidhar Reddy P., Ravinder V., Synthesis, Spectral Characterization and Antimicrobial Studies of Co (II) Complexes with Tetra dentate Schiff bases Derived from Ortho-Phthaldehyde, J. Adv. Chem., ), 1873-1882, 2014) 26.Singh A.K., Pandey O.P., Sengupta S.K., Synthesis, spectral characterization and biological activity of zinc(II) complexes with 3-substituted phenyl-4-amino-5-hydrazino-1, 2, 4-triazole Schiff bases, Spectrochim. Acta A., 85), 1-6, (2012). 27.Swamy S. J., Pola S., Spectroscopic studies on Co (II), Ni (II), Cu (II) and Zn (II) complexes with a N-macrocylic ligands, Spectrochim. Acta A., 70, 929-933, (2008). 28.Geeta, B., Shravankumar, K., Reddy, P. M., Ravikrishna, E., Sarangapani, M., Reddy, K. K., Ravinder, V., Binuclear cobalt(II), nickel(II), copper(II) and palladium(II) complexes of a new Schiff-base as ligand: Synthesis, structural characterization, and antibacterial activity, Spectrochim. Acta A, 77), 911-915,(2010)29.Budige, G., Puchakayala, M. R., Kongara, S. R., Hu, A., Vadde, R., Synthesis, Characterization and Biological Evaluation of Mononuclear Co(II), Ni(II), Cu(II) and Pd(II) Complexes with New N2O2 Schiff Base Ligands, Chem. Pharm. Bull., 59), 166-171,(2011)30.Shakir M., Chishti H.T.N., Chingsubam P., Metal iondirected synthesis of 16-membered tetraazamacrocyclic complexes and their physico-chemical studies, Spectrochim, Acta A., 64), 512-517, (2006). 31.Prasad, A., Reddy, P. M., Shanker, K., Rohini, R., Ravinder, V., Application of nickel-catalysed reduction and Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(6), 66-72, June (2014) Res. J. Chem. Sci. International Science Congress Association 72 azo dye reactions for the determination of tinidazole, Color. Technol., 125), 284-287,(2009)32.Reddy, P. M., Rohini, R., Krishna, E. R., Hu, A. R., Ravinder, V., Synthesis, Spectral and Antibacterial Studies of Copper(II) Tetraaza Macrocyclic Complexes, Int. J. Mol. Sci., 13), 4982-4992,(2012).33.Reddy, P. M., Prasad, A. V. S. S., Shanker, K., Ravinder, V., Synthesis, spectral studies and antibacterial activity of novel macrocyclic Co(II) compounds, Spectrochim. Acta A, 68), 1000-1006,(2007).34.Reddy, P. M., Prasad, A. V. S. S., Rohini, R., Ravinder, V., Catalytic reduction of pralidoxime in pharmaceuticals by macrocyclic Ni(II) compounds derived from orthophthalaldehyde, Spectrochim. Acta A, 70), 704-712,(2008).35.Reddy, P. M., Shanker, K., Rohini, R., Ravinder, V., Antibacterial active tetraaza macrocyclic complexes of Chromium (III) with their spectroscopic approach, Int.J. ChemTech Res., ), 367-372,(2009)36.Rohini, R., Reddy, P. M., Shanker, K., Hu, A. R., Ravinder, V., Antimicrobial study of newly synthesized 6-substituted indolo[1,2-c]quinazolines, Eur. J. Med. Chem., 45), 1200-1205 (2010)37.Rohini, R., Reddy, P. M., Shanker, K., Hu, A. R., Ravinder, V., Synthesis of Some New Mono, Bis-Indolo[1, 2-c]quinazolines: Evaluation of their Antimicrobial Studies, J. Braz. Chem. Soc., 21), 897-904,(2010)38.Rohini, R., Reddy, P. M., Shanker, K., Ravinder, V., New Mono, Bis-2,2-(arylidineaminophenyl) benzimidazoles: Synthesis and Antimicrobial Investigation, Acta Chim. Slov., 56), 900-907,(2009)39.Rohini, R., Shanker, K., Reddy, P. M., Ho, Y.-P., Ravinder, V., Mono and bis-6-arylbenzimidazo[1,2-c]quinazolines: A new class of antimicrobial agents, Eur. J. Med. Chem., 44, 3330–3339,(2009). 40.Rohini, R., Shanker, K., Reddy, P. M., Ravinder, V., Synthesis and Antimicrobial Activities of a New Class of 6- Arylbenzimidazo[1,2-c]quinazolines, J. Braz. Chem. Soc., 21), 49-57,(2010)41.Shanker, K., Ashok, M., Reddy, P. M., Rohini, R., Ravinder, V., Spectroscopic characterization and antibacterial activities of Mn(III) complexes containing the tetradentate aza Schiff base ligands, Int.J. ChemTech Res., ), 777-783,(2009)42.Agh-Atabay N. M., Dulger B., Gucin F., Structural characterization and antimicrobial activity of 1, 3-bis (2- benzimidazyl)-2-thiapropane ligand and its Pd(II) and Zn(II) halide complexes, Eur. J. Med. Chem., 40, 1096-1102, (2005)