Electronic Spectra of Phthalonitrile Isolated in an Argon Matrix

Abstract

The absorption, emission, and magnetic circular dichroism of phthalonitrile (1,2-dicyanobenzene) isolated in an argon matrix are reported between 19 000 and 82 000 cm-1. These spectra are interpreted in terms of parent transitions involving the benzene ring and cyano substituents. The matrix isolation technique affords well-resolved vibrational structure, which permits the determination of vibrational frequencies for the two lowest lying singlet excited states. Contrary to the conclusions of earlier workers, the spin-conserving transitions are Franck-Condon allowed.