Topological Effects in Electron Transfer: Applications to Dendrimers and Branched Molecules

Abstract

Dendrimers belong to a class of complex hyperbranched structures through which electron transfer has been observed; in this work, we study the effect of the bridge topology on long-range transfer. Electron-transfer rates for bridge-mediated electron transfer are calculated by solving the steady-state Liouville equation with phenomenological corrections for solvent interaction. While the behavior of linear bridge groups is well-known, branched structures display interesting electron transport properties. Addition of a small side group with nodes equivalent to the bridge nodes increases the steady-state rate, and this effect is amplified by increasing the site−site couplings in the side group. The effect for a single side group is small, but increases with each additional side group producing a noticeable increase in electron transfer rates for structures with several side groups such as dendrimers. Addition of an electron withdrawing side group at the acceptor end of the bridge creates a structure that can...