Exciplex Processes Involving Trans Naphthylethylenes. Implications of Ground-State Conformeric Equilibria

Article abstract of DOI:10.1021/j100233a020

Five arylethylenes with 1-naphthyl, 2-naphthyl, and phenyl groups in 1,2-positions have been studied for single-mediated charge-transfer interactions with several amines and paraquat dication. 1-Phenyl-2-(2-naphthyl)ethylene and 1,2-di(2-naphthyl)ethylene exhibit distinct dependence of exciplex emission maxima and lifetimes, and fluorescence quenching constants, on excitation and/or monitoring wavelengths; this is in conformity with the existence of ground-state rotamers for these systems, with distinguishable absorption-emission spectra and fluorescence lifetimes.The fluorescence quenching by aromatic amines and paraquat dication occurs with rate constants in the limit of diffusion control and is accompanied by the formation of radical ions in polar solvents (acetonitrile).The transient spectra and kinetics associated with the radical ions, observed by 337.1- and 355-nm laser flash photolysis, are also reported.