Is the trinuclear complex the true reducing species in the Cp2TiCl2/Mn- and Cp2TiCl2/Zn-promoted pinacol coupling?

Abstract

Through a combination of kinetic, voltammetric and product analysis, it has been found that a common Ti^III species obtained from the metal reduction of Cp₂TiCl₂ is involved in the electron transfer to benzaldehyde. A common species in the pinacol dimerization step was also demonstrated. In neither of the two steps is it necessary to invoke trinuclear complexes as previously proposed.