Sensitized photodecomposition of phenyl azide and α-naphthyl azide

Abstract

The photodecomposition of phenyl azide and α-naphthyl azide can be induced by triplet sensitizers (aromatic ketones) and by singlet sensitizers (aromatic hydrocarbons). From a comparison of transfer rates with sensitizer energies, and from the spectra and the oxidation potentials of the azides, it appears that two different mechanisms may operate concurrently in azide sensitization: (1) spin-allowed energy transfer, including transfer to thermally populated non-linear azide ground states, and (2) electron transfer from the ground state of the azide to the excited state of the sensitizer. Mechanism 1 is probably general, mechanism 2 is restricted to aromatic azides.