Disproportionation of Rh^II(cod) to Rh^I(cod) and Rh^III(cycloocta-2,5-dien-1-yl):  Hydrogen Atom Transfer vs Electron and Proton Transfer

Abstract

One-electron oxidation of [(dpa)Rh I (cod)] + yields [(dpa)Rh II (cod)] 2+, which reversibly binds dioxygen. In solution [(dpa)Rh II (cod)] 2+ disproportionates to [(Hdpa)Rh I (cod)] 2+ and two isomers of [(dpa)Rh III (cyclooctadienyl)] 2+ . This reaction proceeds most likely via abstraction of an allylic hydrogen atom by the Rh II metallo radical.