EPR AND ENDOR OF PERFLUOROALKYL RADICAL INTERMEDIATES IN THE REACTION BETWEEN PERFLUOROHYPOFLUORITES AND PERFLUOROALKENES
Source: JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS
Volume: 91 Issue: 21 Pages: 3813-3820
DOI: 10.1039/ft9959103813 Published: NOV 7 1995
EPR and ENDOR spectra of the reaction products of sterically hindered perfluoroalkenes with perfluoromethyl hypofluorite and with the perfluoroether hypofluorite X(CF2O)(n)(CF2CF2O)(m)CF2OF, where X is either OCF3 or a second hypofluorite group OCF2-OF, have been recorded. Tertiary and secondary free radicals are produced by the addition to the alkene double bond of a fluorine atom or of the partner radical formed by the homolysis of the hypofluorite O-F bond. Analysis of the spectra reveals that hyperfine splitting by F-19 nuclei in the gamma and delta positions, and even further from the radical centre, contribute spectra. The alpha- and beta-F-19 hyperfine splitting are discussed in relation to the radical structure and conformation. The beta-F-19 splittings are accounted for by the well known equation a(F)(beta) = B cos(2)(theta); different values of the constant B have to be used according to the number of beta-fluorine substituents bonded to the same alpha-carbon.