A benzoquinone Di-imine from the oxidation of pentafluoroaniline by hypochlorite. X-Ray crystal structure and possible formation via pentafluorophenylnitrene

Abstract

Oxidation of pentafluoroaniline by aqueous sodium hypochlorite under phase-transfer conditions gave decafluoroazobenzene (2), octafluorophenazine (3), and the dark red N-chloro-N′-(pentafluorophenyl)-2,3,5,6-tetrafluorobenzo-1,4-quinone di-imine (4) as a mixture of Z- and E-isomers. X-Ray diffraction studies revealed that this chloro imine gives crystals containing both isomers, the structures of which have been solved. Singlet pentafluorophenylnitrene is proposed to be an intermediate in the oxidation reaction whereby compounds (2), (3), and (4) are formed following nucleophilic attack by pentafluoroaniline on the nitrogen atom, and the ortho- and para-positions respectively. A convenient, albeit not high yielding, procedure for the preparation of decafluoroazobenzene is described.