The scope and limitations of cyanide groups as direction labels for the conformational analysis of matrix-isolated molecules of low symmetry: Part 1: Light-induced infrared dichroism of matrix-isolated 2- and 4-cyanophenyl azides

Abstract Photolysis of 2- and 4-cyanophenyl azides in solid N 2 matrices at 12–20 K yielded anisotropic samples with linearly dichroic infrared spectra. An attempt was made to use the observed dichrosim, largely qualitatively, to correlate the directions of CN bonds with other bond directions in the molecules, thus developing a method of conformational analysis for matrix-isolated molecules. By this means, improved estimates for the directions of the transition moments of the azide stretches and the photo-active electronic absorptions were derived, and 2-cyanophenyl azide was shown, with a high degree of probability, to exist mainly as the anti conformer. Overlap of product and starting material v (CN) bands, however, proved to be a serious disadvantage of this approach.