Unstable intermediates. Part 133.—Electron spin resonance studies of 1-monochloro and 1,1-dichloro radicals formed from irradiated alkyl chlorides and α-chlorocarboxylic acids

Abstract

Exposure of various organic chlorides to ⁶⁰Co γ-rays gave a range of radical products detected by e.s.r., prominent amonst which were 1-chlororadicals. Powder spectra for these radicals at S-, X- and Q-band frequencies are exemplified and interpreted with the aid of results from single crystals. The influence of the quadrupole moment of chlorine on these spectra is discussed.

Methyl chloride gave mainly H₂ĊCl radicals at 77 K, whilst methylene chloride gave H₂ĊCl and HĊCl₂ radicals. Monochloroacetic acid gave HĊCl(CO₂H) radicals at room temperature. Dichloroacetic acid gave Cl₂ĊCO₂H radicals, and the amide gave corresponding radicals. In aqueous or methanolic solutions dichloroacetate ions gave both Cl₂ĊCO^–₂ and ClĊHCO^–₂ radicals, but trichloroacetate ions gave only Cl₂ĊCO^–₂ radicals.