Vibrational spectra and structure of 1-phenyltetrazole and 5-chloro-1-phenyltetrazole: A combined study by low temperature matrix isolation and solid state FTIR spectroscopy and DFT calculations

Abstract

Infrared spectra of 1-phenyltetrazole (C7N4H6) and 5-chloro-1-phenyltetrazole (C7N4H5Cl) isolated in argon matrixes (T=8 K) and in the solid state (at room temperature) were studied. DFT(B3LYP)/6-31G* calculations predict the minimum energy conformation of 1-phenyltetrazole as being non-planar, with the two rings (phenyl and tetrazole) twisted by 29°. For 5-chloro-1-phenyltetrazole, the optimized dihedral angle between the two rings is larger (48°). The theoretically calculated IR spectra of both compounds fit well the spectra observed experimentally. This allowed a reliable assignment of observed IR absorption bands.