Electronic coupling in inter‐ and intramolecular donor‐acceptor systems as revealed by their solvent‐dependent charge‐transfer fluorescence

Abstract

Abstract The solvent dependence of the radiative‐rate constant of both inter‐ and intramolecular donor‐acceptor systems reveals the occurrence of significant intensity borrowing from one or more local transitions. This phenomenon appears to be especially pronounced in systems of the type D‐3σ‐A, where donor and acceptor interact via through‐bond interaction over a relay of three σ bonds. Within the context of a three‐state model, involving the no‐bond state (DA), the charge transfer state (D + A − ) and a single locally excited state [(DA)*], a simplified method is given to analyse the electronic coupling elements between these states.