Interference effects on through-bond electronic interaction propagation

The propagation of an electron donor–acceptor interaction through a molecular structure is described by using the Greenʹs function formalism, with orbital decimation to reduce the system to a two-level representation. Analytical expressions for the effective donor/acceptor energy and coupling show the effect of destructive interference of pathways created by side bonds or lone pairs, respect to the main chain pathway. Application for model systems suggests that destructive interference will make saturated bridging groups, and particularly with lone pairs, less efficient than unsaturated groups, for donor–acceptor interaction propagation through a σ-bond pathway.