Superexchange-mediated electronic energy transfer in a model dyad

On the basis of time-dependent density functional theory (TD-DFT) calculations coupled to the polarizable continuum model (PCM) and single molecule spectroscopic studies, we provide a detailed investigation of excitation energy transfer within a model bi-chromophoric system where a perylene monoimide (PMI) donor is bridged to a terrylene diimide (TDI) acceptor through a ladder-type pentaphenylene (pPh) spacer. We find that the electronic excitation on the PMI donor significantly extends over the bridge giving rise to a partial charge transfer character and inducing a approximately 3-fold increase in the electronic interaction between the chromophores, which explains the failure of the Först…