STUDIES ON BIS(VANILLIN)BENZIDINE COMPLEXES OF TITANIUM(III), VANADIUM(III), IRON(III), MANGANESE(II), COBALT(II) AND NICKEL(II)

The complexes of bis(vanillin)benzidine (vn2bz) of the type [M(vn2bz)( H2O)2Cl2]2Cl2 [where M = Ti(III), V(III) and Fe(III)] and [M(vn2bz)(H2 O)Cl]2Cl2 [where M = Mn(II), Co(II) and Ni(II)] have been synthesized and characterized on the basis of elemental analyses, molar conductanc es, thermogravimetric analyses, magnetic moments, infrared and electro nic 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 act s as a nonfunctional bidentate chelating agent. The complexes of titan ium(III), vanadium(III), and iron(III) are found to be hexa-coordinate octahedral, whereas manganese(II), cobalt(II), and nickel(II) complex es are tetra-coordinate tetrahedral.