title: Superexchange-mediated electronic energy transfer in a model dyad.
abstract: 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 Förster model in reproducing the observed energy migration rates when treating PMI as the donor. However, despite an increased charge transfer contribution in the effective donor state, the increase in solvent polarity is not accompanied by an enhancement in the electronic coupling between the subunits, which is rationalized from a detailed analysis of the excited-state wavefunctions.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 Canada.
authors.forename: Carles
authors.initials: C
authors.lastname: Curutchet
authors.forename: Florian A
authors.initials: FA
authors.lastname: Feist
authors.forename: Bernard
authors.initials: B
authors.lastname: Van Averbeke
authors.forename: Benedetta
authors.initials: B
authors.lastname: Mennucci
authors.forename: Josemon
authors.initials: J
authors.lastname: Jacob
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.forename: Thomas
authors.initials: T
authors.lastname: Basché
authors.forename: David
authors.initials: D
authors.lastname: Beljonne