Transient Charge-transfer Complexes with Chlorine Atoms by Pulse Radiolysis of Carbon Tetrachloride Solutions

Abstract

CHARGE-TRANSFER complexes are known as transient species in reactions of free radicals. This is because of the relatively high electron affinities of some radicals (Table 1). There are reports of solvent effects1 and of the vapour phase halogenation of aromatic compounds2 which show the possible influence of such complexes on reaction mechanisms. So far only very limited proof for the existence of these complexes is available. Charge-transfer complexes with iodine atoms3–5 and with bromine atoms6,7 as electron acceptors have been detected by flash photolysis and pulse radiolysis. This communication reports charge-transfer complexes of chlorine atoms seen during pulse radiolysis of carbon tetrachloride solutions of aromatics. In an earlier communication8 the typical behaviour of very short-lived transients (of the order of µsec) was reported. These have now been identified as charge-transfer complexes of chlorine atoms with aromatic solutes.