THERMAL AND PHOTOCHEMICAL BEHAVIOR OF TRIPLET ARYLNITRENES

The photolysis of phenyl azide, p-nitrophenyl azide and p-methoxyphenyl azide (77 K) yielding the corresponding nitrenes and further paramagnetic intermediates was investigated using u.v. and e.p.r. spectroscopy. After warming up to room temperature the photolyzed solutions were analyzed by h.p.l.c. The formation of triplet nitrene is proved by the respective e.p.r. signals. Depending on the excitation wavelength at 77 K it is possible to excite the thermally stable triplet nitrenes. The electronically excited triplet nitrenes react with the solvent or with the matrix forming the corresponding primary aniline. The radicals (e.g. formyl) observed at longer irradiation times are the result of the photolysis of the formed aniline.