Low-temperature pulse radiolysis. I. Negative ions of halogenated compounds

The absorption spectra and kinetic behavior of the species produced in irradiated ethanol solutions of 1- and 2-chloronaphthalenes, 4-chlorobiphenyl, 1- and 2-bromonaphthalenes, and 2and 4-bromobiphenyls were studied using pulse radiolysis at 100 deg K. The spectra observed are ascribed to the parent negative ions of these halogenated compounds. The negative ions of the chlorinated compounds have long lifetimes and an appreciable part remains even at a few seconds after the pulse. On the other hand, the negative ions of the brominated compounds disappear in a complicated manner within 100 msec. Ethanol solutions of 1,2,3trichlorobenzene and tetrachloroethylene give intense absorptions in the ultraviolet region which may also be ascribed to the negative ions of these solutes. Pulse radiolysis of ethanol solutions of benzyl chloride gives only absorption due to benzyl radicals. The negative ion of benzyl chloride dissociates into a benzyl radical and a chloride ion at 100 deg K. (auth)