Electronic structure and thermal decomposition of 5-aminotetrazole studied by UV photoelectron spectroscopy and theoretical calculations

Abstract

The electronic properties and thermal decomposition of 5-aminotetrazole (5ATZ) are investigated using UV photoelectron spectroscopy (UVPES) and theoretical calculations. Simulated spectra of both 1H- and 2H-5ATZ, based on electron propagator methods, are produced in order to study the relative gas-phase tautomer population. The thermal decomposition results are rationalized in terms of intrinsic reaction coordinate (IRC) calculations. 5ATZ yields a HOMO ionization energy of 9.44 ± 0.04 eV and the gas-phase 5ATZ assumes mainly the 2H-form. The thermal decomposition of 5ATZ leads to the formation of N 2, HN 3 and NH 2CN as the primary products, and HCN from the decomposition of a intermediate CH 3N 3 compound. The reaction barriers for the formation of HN 3 and N 2 from 2H-5ATZ are predicted to be ≈228 and ≈150 kJ/mol, at the G2(MP2) level, respectively. The formation of HCN and HNNH from the thermal decomposition of a CH 3N 3 carbene intermediate is also investigated.