The photochemistry of beta-naphthoyl azide and 4-acetylphenoxycarbonyl azide: The chemical and physical properties of acylnitrenes

We have examined the chemical and physical properties of two acylnitrenes, 4-acetylphenoxycarbonylnitrene (APN) and ;APN is a ground state triplet nitrene which appears to be no more than 5 kcal/mol below the lowest energy singlet nitrene. The properties of APN are dominated by those typically associated with triplet nitrenes: nonstereospecific addition to olefins and a readily detectable electron spin resonance spectrum.;BNN is the first bona fide example of an acylnitrene with a singlet ground state. The properties of BNN are those typically associated with singlet nitrenes: direct or triplet sensitized irradiation of BNA gives products derived exclusively from the singlet nitrene.