Valence-bond isomer chemistry. Part VII. Photochemical interconversion of the perfluoroxylenes

Abstract

U.v. irradiation in the vapour phase interconverts the perfluoroxylenes, with perfluoro-o-xylene the most photo-chemically reactive, and perfluoro-p-xylene the least. The process probably occurs via para-bonded and prismane valence-bond isomers, and of the possible six isomers of the former type, perfluoro-1,2-, 1,3-, and -2,5-dimethyl-bicyclo[2.2.0]hexa-2,5-diene have been characterised, and the 2,3- and 2,6-isomers tentatively identified.

Perfluoro-1,3-dimethylbicyclo[2.2.0]hexa-2,5-diene undergoes the expected addition of bromine to the CF:CF bond, and substitution by sodium methoxide of the fluorine atom of the CF:C·CF₃ double bond.