Synthesis, structural characterization and electrochemical activity of oxidovanadium(IV/V) complexes of a diprotic ONS chelating ligand

The present work reports the chemistry of a few oxidovanadium(IV) and (V) complexes of the ONS chelating ligand S-benzyl-β-N-(2-hydroxyphenylethylidine) dithiocarbazate (H2L). Major objective of this work is to arrive at some general conclusions about the influence of binding environment generated by the replacement of an O-donor center by a S-donor point in a ligand (of a similar arrangement of the other O- and N-donor points) on the redox behavior and on the structural features of comparable [VO(OEt)(ONS)] and [VO(OEt)(ONO)] complexes. Synthesis, characterization by various physicochemical techniques (UV–Vis, IR, EPR and elemental analysis), exploration of electrochemical activity of the oxidovanadium(V) complex [VVO(OEt)L] (1), the mixed ligand complex [VVO(N–O)L] (3) (where N–O is the mono anion of 8-hydroxyquinoline) and a binuclear complex [VVO(OEt)L]2(μ-4,4′-bipy) (2) are reported. Similar studies on of mixed ligand oxidovanadium(IV) complexes of the formula [VVO(N–N)L] (4,5) (where N–N = 2,2′-bipy and o-phen) are also presented here. The [VVO(OEt)L] complex is pentacoordinated and distorted square pyramidal, while the [VIV(N–N)L] complexes are hexacoordinated and octahedral. Structural features of the complex 1 were compared with the corresponding aspects of the previously reported analogous complex [VVO(OEt)(ONO)] (1′).

Graphical abstractExploration of structural, electrochemical and chemical reactivity some new oxidovanadium(IV/V) complexes of a diprotic tridentate ONS chelating ligand is reported. Structural features, spectroscopic and electrochemical properties of the complex 1 involving a ONS donor ligand are compared with a similar type oxidovanadium(V) complex of a ONO donor ligand.Figure optionsDownload full-size imageDownload as PowerPoint slide