Influence of the donor chemical structure on the effective distance in photoinduced electron transfer

In the context of the finite sink approximation, a parametrization of diffusion-limited electron transfer quenching of 9,10-dicyanoanthracene fluorescence by ‘π’ and ‘n’ donors is reported. The effective transfer distance R increases with exergonicity for ‘π’ donors (as shown by previous authors) and for ‘n’ donors although in a different manner. Therefore, our caveat about the necessity of distinguishing ‘π’ from ‘n’ donors for quenching rates is confirmed by the investigation of the effective transfer distance. This is illustrated by a detailed discussion of the data concerning a mixed donor: benzylamine.