Synthesis of new intramolecular charge transfer A-D-A tetrathiafulvalene-fused triads exhibiting large solvent sensitive emission behavior

We have synthesized three new acceptor-donor-acceptor (A-D-A) triads incorporating the donor tetrathiafulvalene (TTF) fused with acceptors quinoxaline and dipyrido[3,2-a:2′,3′-c]phenazine (dppz) systems. Solution emission spectral studies of all these compounds show large solvent sensitive behavior with huge Stokes shifts. The large solvent dependence of the emission indicates that the excited state is stabilized in more polar solvents due to the intramolecular charge transfer. We have also described electrochemical studies of one of the title compounds (compound 1b) exhibiting two oxidation responses at 1.02 and 1.31 V versus Ag/AgCl, that correspond to the oxidized species of TTF monocation and dication, respectively.