Synthesis, Characterization, Antimicrobial, MTT assay, DFT study of Co(II), Ni(II), Cu(II) and Zn(II) Complexes with some New Schiff Base Ligands

Novel Schiff base ligand HL was synthesized by the condensation of 3,5- dichlorosalicylaldehyde and 4-phenylsemicarbazide. Co(II), Ni(II), Cu(II) and Zn(II) complexes were synthesized in 1:1 molar ratio of metal to ligand. The structure of the synthesized ligand was established using 1H NMR, IR, Mass spectrometry and the metal complexes were characterized using IR, Mass spectrometry, UV-Vis, powdered XRD and molar conductivity. The thermal stability of the complex was studied by TGA. In DFT studies, the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy taking the 6-31+g (d,p) basis set using Gaussian 09w, several molecular properties were also calculated. The spectral data show that ligand HL behaves as uninegative tridentate. On the basis of spectral studies, an octahedral geometry has been assigned for Co(II), square planar for Cu(II) and tetrahedral for Ni(II) and Zn(II) complexes. The antimicrobial activities were examined against some human pathogenic strains. The MTT assay was screened against mouse fibroblast cell line. The result indicates that metal complexes show increase in cytotoxicity in proliferation to cell line as compared to the free ligand.