Observation of Isotope Effect on Intramolecular Electron Transfer Promoted by Hydrogen Bonding

Abstract

A ferrocene-quinone dyad (Fc-Q) linked with an amide group and Fc-(Me)Q dyad, in which the amide proton acting as a hydrogen-bond acceptor, is replaced by the methyl group, are employed to study the effects of hydrogen bonding between the carbonyl oxygen of the Q^- moiety and N-H proton in the thermal electron transfer reactions. The hydrogen-bonding formation results in remarkable acceleration of the rate of metal ion-promoted electron transfer as compared to the rate of Fc-(Me)Q in which no hydrogen bond is formed. Therefore, H/D effects on thermal electron transfer reactions in Fc-Q, in which amide proton is replaced by dueterium has been examined this time.