LONG-RANGE, PHOTOINDUCED CHARGE SEPARATION IN SOLVENT-FREE DONOR BRIDGE ACCEPTOR MOLECULES

Charge separation in isolated supermolecules, consisting of an aniline or 4-methoxy aniline donor and a cyanonaphthalene acceptor connected by a semirigid bridge, is described in terms of irreversible sequential intramolecular relaxation involving electron transfer from an electronically excited molecular state and electrostatically driven folding. Sequential folding of the charge transfer state extends the energy range of this state, which is accessible by radiationless electron transfer. The analysis of the intramolecular electron transfer dynamics led to agreement between the distance scale for charge separation inferred from energetic and structural data and accounted for the excess energy dependence of the nuclear Franck-Condon vibrational overlap factors.