Oxovanadium(IV) complexes with tridentate dibasic schiff base ligands and 2-(2’-pyridyl)benzimidazole

Abstract

Several tridentate dibasic schiff base ligands with ONO donor set react with VO(OAc)₂ in presence of the neutral bidentate ligand 2-(2'-pyridyl)benzimidazole (PBH) containing iNN donor set to form monomeric and six-coordin4ted complexes of the type [VO(SB) (PBH)] (H₂SB = tridentate schiff bases). These are orange to brown coloured paramagnetic solids with normal magnetic moments. All the complexes exhibit a strong IR band at 960 cm ^-1 due to (V=O). Their EPR spectra are characterised by a single unresolved signal at <i>g </i>= 2.00 ± 0.02. ElectrochemicaI measurements are characterised by oxidation to vanadium(V) and reduction to vanadium(lII) at + 0.98 to + 1.26 V vs SCE and - 1.08 to - 1.50 V vs SCE, respectively. The thermo gravimetric measurements indicate the stability of the complexes and their stepwise thermal decomposition finally giving V₂O₅ as the end product.