Photolysis of aromatic azides. Part 1.—Electronic spectra of aromatic nitrenes and their parent azides

Seven aromatic azides were photolyzed in organic matrices at 77°K. The primary photoproducts are stabilized and their spectra can be recorded. These primary spectra are assigned to nitrenes; they show the general features associated with open shell aromatic structures, they are independent of the solvent and they disappear when the matrix is softened even at low temperature (90°K). Band assignments for the spectra of the nitrenes and their parent azides are given. The effect of nitrogen on the spectrum of the aromatic radical is discussed in terms of the concepts of Dewar and Longuet-Higgins.