Formation and Identification of Aryldiazenyl Radicals Using the ESR Technique

Article abstract of DOI:10.1246/bcsj.59.1877

Aryldiazenyl radicals were formed at -104 - -116 deg C by photoirradiation of cyclopropane solutions of 1-aryl-2-(arylthio)diazenes and of 1-aryl-3,3-dimethyltriazenes in the presence or absence of olefins, and also by irradiation of cyclopropane solutions of substituted 1,2,3-benzothiadiazoles in the presence of di-t-butyl peroxide.The ESR spectra were analyzed and the hfs constants were assigned by reference to the spectra of methyl, 2H, and 15N-labelled aryldiazenyl radicals and to the results of CINDO calculations.Aryldiazenyl radicals are relatively persistent and the -N=N group rotates about the C-N² bond axis.The preferred conformations of the radicals were considered.