ELECTROCHEMICAL GENERATION OF EXCITED TICT STATES .3. ARYL DERIVATIVES OF N,N-DIMETHYLANILINE

The electrogenerated chemiluminescence (ECL) of intramolecular donor-acceptor compounds was studied in acetonitrile electrolyte solutions using the triple-step method. The compounds studied were the p-aryl (3-fluoroanthenyl, 1-naphthyl, 1-pyrenyl and 9-anthryl) derivatives of N,N-dimethylaniline. In the electrogenerated spectra, only the twisted intramolecular charge-transfer (TICT) band was observed. The Feldberg plot analysis indicated that the emitting species (excited TICT states) are formed directly by the electron transfer between the radical cation and radical anion (S-route). High emission efficiences (phi-ECL = 2.7-4.7%) and high population yields of the excited states (phi-ES = 8.3-9.2%) were found. The phi-ES values obtained have been interpreted in the terms of the Marcus theory.