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

A series of binuclear complexes of the type [(mu-OH)((RCoL)-L-III)(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 v(Co-Me) 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.