Redox pattern in a group of copper(II) dimers : comments on equipotential Cu₂ ^II-Cu^IICu^I and Cu^IICu^ICu₂ ^II couples

Abstract

The redox activity of four oximato-bridged strongly exchange-coupled copper(II) dimers is examined using cyclic voltammetry and coulometry in acetonitrile solution. A well-defined quasi-reversible couple corresponding to the process Cu₂ ^II + e⇌ Cu^IICu^I is observed in all cases. The couple corresponding to the next stage of reduction Cu^II Cu^II + e ⇌Cu₂ ^I is identified in two complexes. The E°₂₉₈ values for the various couples are reported with rationalisation of observed trends in terms of exchange interaction and ligand 10 Dq. The circumstances which may lead to superposition of the two successive one electron couples in copper(II) dimers are discussed.