A highly soluble asymmetric perylene-bis (dicarboximide)-acceptor system incorporating a methylene bridged methoxybenzene-donor: Solvent dependence of charge transfer interactions

The synthesis and photophysical properties of an asymmetrically substituted perylene-bis(dicarboximide), (PDI), system (1) containing a methylene bridged 4-methoxy-benzene donor and a solubilizing branched C-13 alkyl chain are described. As compared to most PDIs, the fluorescence of 1 is strongly quenched in polar (but not in non-polar) solvents due to a photo-induced electron transfer process. Transient absorption spectroscopy and time resolved emission in e. g. acetonitrile indicates that upon excitation the radical anion of the PDI is formed with a rate of ca. 3.5 x 10(9) s(-1), and the charge transfer state has a lifetime of ca. 3 ns. A Frontier Molecular Orbital description is provided, by using DFT calculations.