Solvation of TICT states in solvent mixtures

The formation of the twisted intramolecular charge transfer (TCIT) state of 4,4'-dimethylaminobenzonitrile (DMABN) depends on solvent relaxation around the giant dipole. In solvent mixtures, dielectric enrichment of the polar solvent in the solvation shell can become the rate limiting kinetic step. The translational and rotational solvent relaxations around DMABN in the course of TCIT state formation raise interesting questions concerning the time scale of the actual electron transfer step in other types of electron transfer reactions, in particular intermolecular processes which involve exciplex intermediates