A STUDY OF THE VACUUM PYROLYSIS OF 1,2,3-BENZOTRIAZINES - THE HEI ULTRAVIOLET PHOTOELECTRON-SPECTRA OF BENZAZETE AND O-BENZYNE

A CW CO2 laser is used as a directed heat source to carry out the vacu um pyrolysis of 1,2,3-benzotriazine (1a) and 4-methyl-1,2,3-benzotriaz ine (Ib). We report the first HeI photoelectron (pe) spectrum of benza zete (2a), which correlates with ionization energies calculated with H AM/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 th is study correlates with the spectrum published by Zhang and Chen, but not with the spectra reported in two earlier publications.