Vibrational spectroscopy of triazoles and tetrazole

This work deals with the analysis of vibrational spectra of three five membered nitrogen heterocycles, the parent compounds: 1,2,3-triazole, 1,2,4-triazole and tetrazole, and their N-deuterated derivatives. The infrared spectra of these compounds were recorded in condensed states, while the Raman spectra were measured without polarization and using both parallel and perpendicular polarizations of scattered light. The fundamental vibrational frequencies were calculated applying the density functional theory with the Becke3P86 functional and the 6-311G(d,p) basis set. The results of the calculations were utilized in the assignment of the vibrational fundamentals, and the measured fundamental frequencies were used to refine the Vibrational force constants. The considerable association of these compounds in condensed phase caused shifts of some fundamental frequencies of the isolated molecules. Nevertheless, the relative mean deviations between the measured and calculated frequencies were about 1 % or less for every investigated molecule. (C) 2000 Elsevier Science B.V. All rights reserved.