Organometallic cobalt(iii) complexes with tridentate imino-oximic ligands: structural, spectroscopic and electrochemical properties

Abstract

A series of binuclear complexes of the type [(μ-OH)(RCo^IIIL)₂]⁺ were L is the tridentate 2-(2-pyridylethyl)imino-3-butanone oximato ligand and R = Me, Et, CH₂CF₃, CH₂Cl or Cy have been prepared and characterised. Some of their physico-chemical properties, namely the Co–R bond lengths, the ν_Co–Me Raman frequencies and the E_1/2 half-wave potentials of the one-electron reduction process have been determined. Comparison of these properties with those of the metalloorganic derivatives containing tetradentate ligands, such as cobaloximes, Costa model derivatives and cobalamins, suggests that in the present compounds the Co–C bond strength and the electrochemical behaviour are more influenced by electronic than by steric factors.