REVERSIBLE CHARGE MIGRATION IN THE EXCITED-STATE OF AN ELECTRON DONOR-DONOR-ACCEPTOR SYSTEM DETECTED VIA DELAYED CHARGE-TRANSFER FLUORESCENCE

Trichromophoric electron donor-donor-acceptor compounds are described which emit fluorescence exclusively from a charge-separated state best described as D(2)D(1)(+)A(-). This state, which has a dipole moment m u(e) approximate to 24 D, is formed quantitatively upon excitation of the electron acceptor chromophore. In solvents of moderate polarity su bsequent electron transfer from D-2 to D-1, leading to the formation o f the D(2)(+)D(1)A(-) State (mu(e) approximate to 42 D), can occur in a reversible fashion. This reversibility gives us the unique opportuni ty to experimentally investigate the energetics of the charge migratio n D(2)D(1)(+)A(-) reversible arrow D(2)(+)D(1)A(-).