Co(II), Ni(II), Cu(II) and Zn(II) complexes of 2-((1H-benzo[d]imidazol-1-yl)(phenyl) methyl)hydrazinecarboxamide (BIBS) and 2-((1H-benzo[d]imidazol-1-yl)(phenyl) methyl) hydrazine-carbothioamide (BIBTS) were synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR, mass, electronic spectra, magnetic moment, molar conductance and EPR studies. The complexes were found to have general formulae [M(BIBS)2Cl2] and [M(BIBTS)2Cl2] [M = Co(II), Ni(II), Cu(II) and Zn(II)]. The IR results demonstrate that co-ordination sites are the azomethine nitrogen and carbonyl oxygen atom of the ligand BIBS, carbonyl sulphur of the ligand BIBTS. The geometry of the complexes is confirmed by measuring number of bands, their energy positions and intensity by electronic and magnetic moment measurement values. The in vitro biological screening effects of the synthesized compounds were tested against various microbial species and the results show that the metal complexes are more biologically active than the free ligand.
Mannich base, Metal complexes of benzimidazole, O, N and O, S donor, Antimicrobial activity