Optical spectra and reactivities of radical anions of 4-nitrobenzyl compounds produced by pulse radiolysis of acetonitrile solutions

Abstract

Electronic absorption spectra are reported for transients formed on pulse radiolysis of acetonitrile solutions of aromatic nitrobenzyl compounds and are assigned to the solute radical anions. Decay of the transients is fairly rapid but is markedly slower in the presence of tetraethylammonium formate. It is suggested that the CH2CN radical is responsible for the rapid decay and that formate ion scavenges this species. With 4-nitrobenzyl chloride, the decay of the transient is observed to be second order, in contrast to electrochemical experiments where first-order decay is observed. With 4-nitrobenzyl fluoride or alcohol, decay of the initially formed transient is accompanied by formation of a new species absorbing at longer wavelength. Identification of the 4-nitrobenzyl chloride anion is supported by first-order decay of the species in water with k = 4 x 103 sec-1 (found by Hayon and Madhavan).