Step-wise and concerted reaction paths triggered by electrochemical, homogeneous, and photoinduced electron transfer

摘要

Electron transfers to or from molecules are often accompanied by a profound reorganization such as the cleavage of a bond. The two steps may occur conceitedly or successively. The model developed for the concerted case is illustrated by many electrochemical and homogeneous examples. Competition between the two pathways depends upon intrinsic molecular factors, but also on the incoming electron (or hole) energy as found in several electrochemical and homogeneous systems. Contrary to common intuition, the quantum yields of photoinduced dissociative electron transfers may well be less than unity on account of partitioning between back electron transfer and product formation. It is thus worth comparing, within the same conceptual framework, electrochemical and photochemical reactions involving the same substrate.