International Journal of Pharma and Bio Sciences. SYNTHESIS AND IN VITRO EVALUATION OF Ni (II) COMPLEXES OF SALICYLALDIMINE ABSTRACT

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1 Int J Pharm Bio Sci 2014 July; 5(3): (P) Research Article Medicinal hemistry International Journal of Pharma and Bio Sciences ISSN SYNTESIS AND IN VITRO EVALUATION OF Ni (II) OMPLEXES OF SALIYLALDIMINE M. ABIRAMI 1 AND V. NADARAJ *2 1 Department of hemistry, Sri Ramakrishna Engineering ollege, oimbatore22, India. 2 Department of hemistry, Tamilnadu ollege of Engineering, oimbatore59, India. ABSTRAT Schiff bases and their metal complexes are very important in medicinal and pharmaceutical fields because of their wide spectrum of biological activities. Transition metal complexes derived from the Schiff base ligands with biological activity have been widely studied. A series of Ni (II) complexes were prepared by the reaction of salicyldimine with Nickel Oxide at room temperature. The chemical structures of metal complexes were confirmed by spectroscopic analysis and all of the compounds were evaluated for their antimicrobial properties. All the Ni (II) complexes have been found to exhibit moderate or good activity against most bacteria and fungi species. KEYWORDS : complex, Schiff base, antimicrobial, copper V. NADARAJ Department of hemistry, Tamilnadu ollege of Engineering, oimbatore59, India. *orresponding author P 593

2 Int J Pharm Bio Sci 2014 July; 5(3): (P) INTRODUTION Nowadays, the research field dealing with Schiff base coordination chemistry has expanded enormously. The importance of Schiff base complexes of bioinorganic chemistry, biomedical applications, supra molecular chemistry, catalysis and material science, separation and encapsulation processes, and formation of compounds with unusual properties and structures has been well recognized and reviewed 1. Schiff bases of hydroxy aldehydes and ketones were widely used in coordination chemistry for the preparation of metal complexes 2,3. Schiff bases and their coordination compounds have been gained importance nowadays as they are useful in biochemical 4, anticancer 5, antiinflammatory 6, antimicrobial 7 and antipyretic 8, among others. Some of them have been used as complexing agent 9,10 and powerful corrosion inhibitors 11. The present article we demonstrate the synthesis of Nickel complexes from salicyldimine Schiff base. All the synthesized metal complexes were screened for their antimicrobial activity. Further the structures of synthesized compounds were confirmed by elemental analysis and spectral studies. MATERIALS AND METODS Melting points (mp) were determined using Boetieus micro heating table and are uncorrected. IR (KBr, cm 1 ) spectra were obtained on Shimadzu8201 spectrophotometer. 1 NMR spectra were recorded on Bruker AMX400 (400 Mz) spectrometer using TMS as an internal reference (hemical shifts in δ, ppm) and solvent DMSOd 6. Elemental analyses were performed on Perkin Elmer Nanalyzer. Mass spectra were recorded on Shimadzu GMSQP5050A (70 ev) mass spectrometer. For microwave irradiation a Kenstar (OM 20ESP, 2450 Mz) domestic microwave oven was used. Synthesis of ligands A mixture of respective anilines and salicylaldehyde was taken in a 50 ml beaker and mixed well. The mixture was irradiated in a microwave oven at power of 160 W for the specified time (Table 1). The reaction was monitored by thin layer chromatography (TL) and spots were visualized in iodine chamber. After completion of the reaction, the reaction mixture was poured into ice water. The yellow solid obtained was filtered, washed, dried and recrystalised from ethanol. Preparation of complexes The salicylaldimine Schiff base (0.01 mole) and Nickel Oxide (0.015 mole) in 25 ml Methanol were mixed. An immediate colour change shows the formation of complex. The solution stirred for 1hr and kept at room temperature overnight. Solid complex thereafter separate out washed with distilled water to remove excess of metal and dried in vacuum. The structures of the ligands and metal complexes are shown in scheme1 Scheme 1 Synthesis of Ni (II) omplexes P 594

3 Int J Pharm Bio Sci 2014 July; 5(3): (P) Microbial Activity All the synthesized compounds were screened for their antibacterial and antifungal activities. For preliminary screening, the antimicrobial tests were carried out by discdiffusion method 12. One hundred µl of suspension containing 10 8 FU/ml of bacteria, 10 6 FU/ml of fungi were spread on Muellerinton agar medium (MA) and Sabouraud s dextrose agar (SDA) medium respectively. The discs (6 mm in diameter), impregnated with 10 µl of the test compounds (500 µg/disc and 1000 µg/disc) at the concentration of 50 mg/ml and 100mg/ml were placed on the inoculated agar. Negative controls were prepared using the same solvent (DMSO) employed to dissolve the test compounds. Ofloxacin (5 µg/disc) and lotrimazole (10 µg/disc) were used as positive reference standard to determine the sensitivity of each microbial species tested. The inoculated plates were incubated at 37 for 24 hours and 27 for 72 hours for bacteria and fungi strains respectively. Antimicrobial activity was evaluated by measuring the diameter of the zone of inhibition against test organisms (Table 5). RESULTS AND DISUSSION Schiff base salicylaldimine was synthesized by the condensation of substituted aryl amine with salicylaldehyde. Equmolar ratio of Nickel oxide and salicylaldimine schiff base dissolved in 25 ml of methanol and stirred for 2 hr at room temperature. An immediate colour change obtained, it confirm the formation of metal complex. All the synthesized compounds are colored and stable to air and moisture. The yields of the complexes about 8290%. The metal complexes are generally only soluble in DMF and DMSO. The synthetic procedure of ligand salicylaldimine and its metal complexes are presented in Scheme 1. omparison of IR spectra of the schiff base and complexes to determine the coordination sites that may be involved in coordination. Based on the comparison it was determined that the v(=n) stretching vibration is found in the Schiff base at 1600 to 1615 cm 1. This band shifted to lower wave numbers in the complexes indicating the participation of nitrogen in coordination. The new bands at v (MN) stretching vibrations were appearing at cm 1 in the spectra of metal complexes. In the 1 NMR spectra, the signal for the azomethine proton appearing as a singlet at ppm in the spectra of ligands was downfield shifted in the spectra of Ni (II) complexes at ppm. This deshielding was attributed to the donation of the lone pair of electrons on the azomethine nitrogen to the Nickel ion, resulting in the formation of a coordinate bond. 1 NMR spectra of ligands exhibited a multiplet between the region ppm for aromatic hydrogens. In the spectra of Ni (II) complexes, these peaks have downfield shifts which can be attributed to the increased conjugation upon complex formation. The intense singlet at ppm for group in spectra of Ligands disappeared in the spectra of Ni (II) complexes 3ag. This refers to the complex formation occurring via the deprotonation of the group. The changes and downfield shifts in the spectra of copper complexes are good indications for participation of these groups in the coordination with the metal ions, and give further support for the presence of the metal ions. All the compounds have elemental analysis consistent with their formulations. The elemental analytical data of the complexes reveal a metal to ligand ratio is 1:1. The physical and analytical data of salicylaldimine and its metal complexes are given in Table 1 & 2 and Table 3 & 4. All the synthesized Ni (II) complexes were tested for antibacterial activity against seven bacteria and five fungi stains (Table 5). The Ni (II) complexes exhibited good antibacterial activity against Escherichia coli and Staphylococcus aureus whereas Bacillus subtilis and Pseudomonas aeruginosa have shown moderate activity. Excellent activity against Bacillus cereus was also shown by 3d followed by good inhibition against Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. In the case of antifungal activity all the tested complexes have shown good activity against both Aspergillus niger and Aspergillus flavus fungi and moderate activity against ladosporium oxysporum and andida albicans. The 3b complexes have shown higher activity P 595

4 Int J Pharm Bio Sci 2014 July; 5(3): (P) against both all the bacterial and fungal strains. The ligands with nitrogen and oxygen donor atoms inhibit enzyme activity, since the enzymes which require these groups for their activity appear to be especially more susceptible to deactivation by metal ions on coordination. Table 1 Analytical and IR Spectral data of Schiff bases 3ae ompound Physical Data IR Spectrum (KBr,cm 1 ) Reaction ν Yield (%) ν Time (min) mpº =N ν (aromatic O stretching ) 1 N OO 2a 2 N l 2b 3 N NO 2 2c 4 N 3 2d 5 N O 3 2e Table 2 Spectral data of Schiff bases 3ae ompound OO 2a N N 2b l N NO 2 2c 2d N 3 N O 3 2e 1 NMR Spectrum (ppm) δ δ δ =N δ O δ 3 δ (Ar) 13 NMR Spectrum (ppm) δ N δ O δ 3 Mass Spectrum (70 ev, m/e) Molecular Formula (M + ) 14 11NO NOl N 2O NO NO P 596

5 Int J Pharm Bio Sci 2014 July; 5(3): (P) Table 3 Analytical and IR Spectral data of Ni (II) complexes 3ae 1 ompound Physical Data IR Spectrum (KBr,cm 1 ) Yield (%) mpº ν =N ν O ν (aromatic stretching ) * Table 4 Analytical and IR Spectral data of Ni (II) complexes 3ae ompound 1 NMR Spectrum (ppm) δ δ δ =N δ O δ 3 δ (Ar) 13 NMR Spectrum (ppm) δ N δ O δ Disap peare d Disap peare d P 597

6 Int J Pharm Bio Sci 2014 July; 5(3): (P) Table 5 In vitro antimicrobial activity of 3ae (µg/disc) by disc diffusion assay Diameter of zone of inhibition in mm 3a 3b 3c 3d 3e A B Microorganisms µg/disc µg/disc µg/disc µg/disc µg/disc µg/disc µg/disc Bacillus subtilis (NIM 2063) a NT Bacillus cereus (NIM 2155) a NT Escherichia coli (NIM 2065) a NT Pseudomonas aeruginosa (NIM 2200) a NT Staphylococcus albus (NIM 2178) a NT Aspergillus niger (NIM 1196) b NT 16 Trichoderma viridie (NIM 1195) b NT 16 Rhodotorula rubra (NIM 3174) b NT 17 Lipomyces lipofera (NIM 3252) b 8 11 NT 18 Aspergillus flavus (NIM 535) b NT 19 a bacteria b fungi ; A = Ofloxacin, B = lotrimazole, No inhibition, NT Not Tested ONLUSION In this article, we have discussed the synthesis of Ni(II) complexes from salcyaldimine Schiff base. The formation of the complex has been confirmed by the analytical data, IR, 1 NMR and mass spectral studies. All Ni (II) complexes were found to exhibit moderate or good activity against most bacteria and fungi species. These studies may serve as a basis for the chemical modifications directed towards the development of a new class of antibacterial agents. REFERENES 1. Singh P, Goel RL, Singh BP, Synthesis, characterization and Bilogical activity of Schiff bases, J Indian hem Soc, 52: , (1975). 2. Raman N, Pitchaikani Raja Y, Kulandaisamy A, Synthesis and characterization of u(ii), Ni(II), Mn(II), Zn(II) and VO(II) Schiff base complexes derived from ophenylenediamine and acetoacetanilide, Proceeding: Indian Academic Science, 113(3): , (2001). 3. Pawlica D, Marszalek M, Mynarczuk G, Sieron L, Eilmes J, New unsymmetrical Schiff base Ni(II) complexes as scaffolds for dendritic and amino acid superstructures, New J hem, 28 (12): , (2004). 4. Shah S, Vyas R, Mehta R, Synthesis, characterization and antibacterial activities of some new Schiff base compounds, J Indian hem Soc, 69 (9): , (1992). 5. Pandeya S N, Sriram D, Nath G, Declercq E, Synthesis, antibacterial, antifungal and antiiv activities of Schiff and Mannich bases derived from isatin derivatives and N[4(4'chlorophenyl)thiazol2yl] thiosemicarbazide, Euro J Pharmceutical Soc, 9(1): 2531, (1999). 6. More P G, Bhalvankar R B, Patter S, Synthesis and biological activity of Schiff bases of aminothiazoles, J Indian hem Soc, 78 (9): , (2001). 7. Anjali J, Yashmeen S, Kumar D N, An innovative Green synthesis of some Schiff bases and their anitmicorbial activity, Int J Pharma Bio Sci, 4(4):197204, (2013). 8. Kuzmin V E, Artemenko A G, Lozytska RN, Fedtchouk AS, Lozitsky VP,. Muratov E N, Mescheriakov A K, Investigation of anticancer activity of macrocyclic Schiff bases by means of 4DQSAR based on simplex representation of molecular structure, SAR & QSAR Environ Res, 16 (13): , (2005). 9. W. Sawodny, R. Grunes,. Reitzle, Reversible O 2 Addition to Polymeric SchiffBase omplexes of V II and Mn II P 598

7 Int J Pharm Bio Sci 2014 July; 5(3): (P) and Their Use as Oxidation atalysts, Urban Inorg him Acta, 29: 6368, (1978). 10. S. Oshima, N. irayama, K. Kubono,. Kokusen, T. onjo., Structural ontrol of Schiff Base Ligands for Selective Extraction of opper(ii), Anal Sci,18(12): , (2002). 11. V.S. Agarwal, K.S.Rajan and P.K. Sen, Synthetic Lubricating oil Greases containing Metal helates of Schiff bases, US Patent , Karaman I, Sahin F, Gulluce M, Ogutcu, Sengul M, Adiguzel A, Antimicrobial activity of aqueous and methanol extracts of Juniperus oxycedrus L, J Ethnopharmacology, 2003, 85(23), P 599