Studies on bis(vanillin)benzidine complexes of titanium(III), vanadium(III), iron(III), manganese(II), cobalt(II) and nickel(II)

Abstract

The complexes of bis(vanillin)benzidine,(vn₂bz)of the type [M(vn₂bz)(H₂O)₂CI₂]₂CI₂[where M=Ti(III), V(III) and Fe(III)] and [M(vn₂bz)(H₂O)Cl]₂CI₂ [where M= Mn(II),Co(II) and Ni(II)] have been synthesized and characterized on the basis of elemental analyses, molar conductances, thermogravimetric analyses,magnetic moments, infrared and electronic spectra. The ligand vn₂bz has six coordination sites. The phenolic OH group (remains unionized) and the methoxy groups do not take part in coordination and remain forbidden sites. Only azomethine nitrogens take part in coordination. Thus: the ligand bis(vanillin) benzidine acts as a nonfunctional bidentate cbelating agent. The complexes of titanium(III), vanadium(III), and iron(III) are found to be hexa-coordinate octahedral, whereas manganese(II),cobalt(II), and nickel(II) complexes are tetra-coordinate tetrahedral.