Reactions of 1,1-diphenyl-2-picryl-hydrazyl with NO2, Cl2 and F2

The reactions of 1,1-Diphenyl-2-picryl-hidrazyl (DPPH) with Cl2, NO2 and F2 were studied. In the para-phenyl position substituted diphenylpicrylhydrazines were formed. Besides this, the reaction of halogens led to products which were nitro-substituted in the para-phenyl position. Thus, it was shown that the reactions of halogens and halogen radicals with DPPH include a substitution at the picryl group of DPPH and its derivatives under liberation of NO2. By ESR in situ spectroscopy and computational analysis of spectra, nitro-, dinitro-, fluoro- and difluoro-diphenylpicrylhydrazyls were identified as transient intermediates. In the formation of these species nitrogen dioxide and fluorine act as oxidants for the corresponding substituted hydrazines. (Author)