Synthesis, characterization, and antibacterial activity of novel Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes with vitamin K-3-thiosemicarbazone

Vitamin K-3-thiosemicarbazone (C12H11N3NaO4S2. 5H(2)O, abbreviated as VT), a new Schiff base derivative, has been synthesized. Its crystal structure, determined by X-ray diffraction, is triclinic, space group P (1) over bar. We have also prepared five novel complexes of VT with transition metals: [M (VT)(2)2H(2)O]. nH(2)O, (n = 1 and 2 for M = Cu(n) and Zn(II), respectively ) and [M'(HVT)(2)Cl-2]. mH2O, (m =4, 5, and 7 for M' =Co(II), Mn(II), and N i(n), respectively). These compounds were characterized by IR and UV-Vis sp ectroscopy, molar conductivity, thermal analyses, complexometric titration, and elemental analysis. In all the complexes, the VT ligand coordinates th rough sulfur and oxygen atoms, and the geometry around metal atom is best d escribed as octahedral, in vitro tests of antibacterial activity showed tha t VT and its complexes with Mn(II), Co(n),Ni(II), Cu(II), and Zn(II) all ha d strong inhibitory actions against G(+) Staphylococcus aureus, G(+) Hay ba cillus, and G(-) Escherichia coli. (C) 2000 Elsevier Science Inc. All right s reserved.