NMR STUDIES OF AROMATIC NITROGEN HETEROCYCLIC COMPOUNDS: BENZOTRIAZOLES

Abstract

Author Institution: Air Force Materials Laboratory (MAYH)The chemical shifts and coupling constants of benzotriazole, its 1-methyl and 2-methyl derivative and its anion and cation have been measured. LAOCOON III was used to iteratively refine the reported parameters. H\""{u}ckel Molecular Orbital calculations were performed in the hope of facilitating the choice of input parameters for the computation of the complex ABCD spectrum of the 1-methylbenzotriazole. No useful correlation was found between $\pi$-electron densities and chemical shifts of the aromatic protons. A deuteration scheme was therefore resorted to in order to unambiguously assign the resonance frequencies of these four protons. Protonation and deprotonation experiments were also performed with benzotriazole to determine the effect of charge on the AA' BB' spectra recorded at room temperature. The NMR and MO data are compiled and compared