Synthesis, characterisation and electrochemical studies of dioxouranium (VI) complexes of dioxolenes with pyridine bases

Abstract

Mixed ligand complexs of the formulae UO₂ (O ͡O) (L---L) (H₂O) (2-5) where O ͡O =dioxolenes viz pyrocatechol (2), tert-butylcatechol (3), di-tert-butylcatechol (4) and tetrachlorocatechol (5) and L---L =pyridine (b), bipyridine (c), <em>o</em>-phenanthroline (d) and dipyridylamine (e) have been prepared and characterised by elemental, IR, UV-vis and thermal analyses. Cyclic voltammograms suggest three successive redox responses. The catechol oxidation is highly sensitive to the nature of the substituents. The low energy transition in the visible region is dependent on the nature of the catechol and pyridine base used. This band is assigned to ligand-to-ligand charge transfer (LLCT) transition and is qualitatively assigned as 3b₁ (cat) &reg;&pi;* (base) transition.