Intramolecular electron transfer in polymers with aromatic side groups as a stepping stone

Abstract

Intramolecular electron-transfer reactions in polymers with aromatic side groups were confirmed by the pulse radiolysis of solutions containing poly(4-vinylbiphenyl-co-1-vinylpyrene). First, the optical absorption spectra and decay reactions of the anions produced by electron pulses in 2-methyltetrahydrofuran containing homopolymers poly(4-vinylbiphenyl) or poly(1-vinylpyrene) were studied. Steady-state optical absorption spectra of these polymer anions produced by {gamma}-radiolysis at 77 K were also studied for comparison. Second, solutions containing the copolymers in which a small number of biphenylyl side groups of poly(4-vinylbiphenyl) were substituted by pyrenyl groups were examined. The transient absorption spectra observed by pulse radiolysis of these solutions clearly showed the existence of the intramolecular electron-transfer process along the polymer chain with the biphenylyl side groups as a stepping stone. The results were analyzed on the basis of a simple one-dimensional random-walk mechanism.