Electron spin resonance studies of the radicals formed from C-nitroso compounds and olefins. Part 1.—Nitrosodurene and fluoro-olefins

Abstract

A detailed investigation has been made of the temperature dependence of the e.s.r. spectra of radicals obtained from the reaction of 2,3,5,6-tetramethylnitrosobenzene (nitrosodurene) with CF₂CFBr, CF₂CFCl and CF₂CCl₂. Thermodynamic parameters for internal rotation have been derived from computer simulations of the spectra: it is suggested that restricted rotation occurs about the beta-carbon–nitrogen bond in the radical ArN(O)CF₂CFXY, where X, Y = F, Br; F, Cl; and Cl, Cl. Temperature and solvent effects on the nitrogen and fluorine hyperfine coupling constants have been measured and explained in terms of planarity changes about the radical centre.