A study of the vacuum pyrolysis of 1,2,3-benzotriazines. The Hel ultraviolet photoelectron spectra of benzazete and <i>o</i>-benzyne

Abstract

A CW CO 2 laser is used as a directed heat source to carry out the vacuum pyrolysis of 1,2,3-benzo-triazine (1a) and 4-methyl-1,2,3-benzotriazine (1b). We report the first HeI photoelectron (pe) spectrum of benzazete (2a), which correlates with ionization energies calculated with HAM/3 using an equilibrium geometry obtained at the ab initio HF/6-31G** level of the theory. The pe spectrum of o-benzyne (3) obtained in this study correlates with the spectrum published by Zhang and Chen, but not with the spectra reported in two earlier publications. Keywords: 1,2,3-benzotriazines, vacuum pyrolysis, HeI ultraviolet photoelectron spectra, benzazete, benzyne.