Synthesis and characterization of mixed-ligand complexes using a precursor mononuclear oxidovanadium(V) complex derived from a tridentate salicylhydrazone oxime ligand

The mononuclear oxidovanadium(V) complex [VO(L)(OEt)(EtOH)] (1), where H2L = Salicyloyl hydrazone of diacetyl monooxime, reacts separately with five different reactants viz. pyridine (py), 4-methylpyridine (4mepy), 4,4′bipyridine (4,4′bipy), 8-hydroxyquinoline (Hox) and KOH to yield the mononuclear oxidovanadium complexes [VO(L)(OEt)(py)] (2), and [VO(L)(OEt)(4mepy)] (3), the binuclear complex [VO(L)(OEt)]2(μ-4,4′bipy) (4), the mononuclear bis chelate complex [VO(L)(ox)] (5) and the water soluble dioxidovanadium salt K[VO2L]·H2O (6) respectively. Complex 5 has been characterized by X-ray crystallography, and crystallizes in the orthorhombic space group Pna21 having a distorted octahedral O4N2 coordination environment. All five complexes are characterized by elemental analysis, various spectroscopic techniques (UV–Vis, IR, NMR and ESI Mass) and cyclic voltammetry. The spectral and electrochemical data of these five complexes are compared with those of the precursor complex.

► Synthesis of mixed-ligand complexes from a oxidovanadium(V) complex.
► Pyridine, 4,4′bipy, 8-hydroxyquinoline (Hox) and KOH were used as reactant.
► Adduct, bridged complex, bis chelate and dioxidovanadium salt were obtained.
► X-ray crystal structure of the bis chelate is reported.
► Spectral and electrochemical properties are compared.