Pure Appl. Chem., 2003, Vol. 75, No. 5, pp. 577-587
doi:10.1351/pac200375050577
Catalytic control of electron-transfer processes*
S. Fukuzumi
Department of Material and Life Science, Graduate School of Engineering, Osaka University, Crest, Japan Science and Technology Corporation, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
Abstract:
Catalytic control of electron-transfer processes is described for a number of photoinduced and thermal electron-transfer reactions, including back electron transfer in the charge-separated state of artificial photosynthetic compounds. The intermolecular and intramolecular electron-transfer processes are accelerated by complexation of radical anions, produced in the electron transfer, with metal ions that act as Lewis acids. Quantitative measures to determine the Lewis acidity of a variety of metal ions are given in relation with the promoting effects of metal ions in the electron-transfer reactions. The mechanistic viability of metal ion catalysis in electron-transfer reactions is demonstrated by a variety of examples of both thermal and photochemical reactions that involve metal ion-promoted electron-transfer processes as the rate-determining steps, which are made possible to proceed by complexation of radical anions with metal ions.