Electronic states of 1,3,5-(sym)-triazine. I. Absorption spectra of pure and mixed crystals

Abstract

Spectra of pure and isotopic mixed crystals of sym-triazine are presented which indicate that the 3455 Å triplet state is E″3(nπ*). These same results confirm previous assignment of the state at 3330 Å as E″3(nπ*). Absorption spectra of sym-triazine in sym-trioxane chemical mixed single crystals are presented and further corroborate these conclusions. Out-of-plane (parallel) vibrations of sym-triazine are considerably affected by crystal fields in both crystal systems. It is demonstrated that assigned state symmetries are not inconsistent with previously obtained experimental results on these states. The nature and type of intermolecular interactions and exciton effects present in the triazine system are briefly discussed. A synthetic route is described which yields substantial quantities of high purity sym-triazine, an absolutely essential part of present and forthcoming work on this system.