Thermodynamic, kinetic and electronic structure aspects of a charge-transfer active bichromophoric organofullerene

Abstract

Our recent work on charge transfer in the electronically push–pull dimethylaminoazobenzene–fullerene C60 donor–bridge–acceptor dyad through orbital picture revealed charge displacement from the n(N = N) (non-bonding) and π (N = N) type orbitals centred on the donor part to the purely fullerene centred LUMOs and (LUMO+n) orbitals, delocalized over the entire molecule. Consequently, this investigation centres around the kinetic and thermodynamic parameters involved in the solvent polarity dependent intramolecular photo-induced electron transfer processes in the dyad, indispensable for artificial photosynthetic systems. A quasi-reversible electron transfer pathway was elucidated with electrode-specific heterogeneous electron transfer rate constants. Solvent polarity controlled kinetic and thermodynamic parameters associated with intra-molecular photo-induced electron transfer processes in an electronically push–pull type dimethylaminoazobenzene–fullerene C60 donor–bridge–acceptor dyad are reported. A quasi-reversible electron transfer pathway is elucidated with electrode-specific heterogeneous electron transfer rate constants for the trans-dyad across the electrode/electrolyte interface.