Oxorhenium(V) complexes with tetradentate NSNO pyridylthioazophenolates: syntheses, spectral and electrochemical studies

A family of oxorhenium(V) complexes of newly designed pyridylthioazophenolate ligands has been synthesized and isolated in pure form. The solid state structure of an organic compound (HL1) has been established by X-ray crystallography. The molecular structure observed in the solid state is that the two molecules of the ligand (HL1) in the asymmetric unit have similar geometries, except for the orientation of the pyridine ring. This series of organic moieties acts as tetradentate monobasic NSNO donor chelators in oxorhenium(V) complexes which has been characterized by elemental analyses, IR, ¹H-NMR, UV–Vis. The complexes are 1:1 electrolytes in nature in MeOH solution, the counter anion being ClO ₄ ⁻ . The electrochemical studies of the [Re^VO(L)Cl]ClO₄ complexes in MeCN using TBAP as supporting electrolyte exhibit quasi-reversible voltammogram showing one-electron couple for [Re^VIO(L)Cl]²⁺−[Re^VO(L)Cl]⁺ in the 1.11–1.29 V vs SCE range.