Molecular Structure, Vibrational Spectra and Photochemistry of 2-Methyl-2H-Tetrazol-5-Amine in Solid Argon

GOMEZ ZAVAGLIA, ANDREA, I. REVA, L. FRIJA, M.L.CRISTIANO Y R. FAUSTO

Funchal, Madeira

Congreso; Matrix-Isolation Spectroscopy 2005 (MATRIX 2005); 2005

Grupo de Espectroscopía a Bajas Temperaturas. Universidad de Coimbra

P3.10- Molecular Structure, Vibrational Spectra and Photochemistry of 2-Methyl-2H-tetrazol-5-amine in Solid Argon R. Fausto, I.D. Reva, L. Frija, M.L. Cristiano and A. Gómez-Zavaglia Department of Chemistry - University of Coimbra - Portugal -, Facultad de Farmacia y Bioquimica - Universidad de Buenos Aires - Argentina -, and Department of Chemistry and Biochemistry - University of Algarve - Faro - Portugal In this work, the molecular structure, infrared spectrum and UV photochemistry of 2-methyl-2H- tetrazol-5-amine (2MTA) isolated in solid argon (10K) were investigated. The experimental studies were supported by extensive DFT(B3LYP)/6-311++G(d,p) calculations. The infrared spectrum of matrix-isolated 2MTA was fully assigned and correlated with structural porperties. Taking into consideration the observed frequency of the NH2 wagging mode, it is suggested that, in the matrices, the amine group becomes slightly more planar than in the gas phase, due to matrix-packing effects. In situ UV-irradiation (l> 235 nm) of the matrix-isolated 2MTA monomer is shown to induce three main primary photochemical processes: (1) tautomerization to mesoionic 3-methyl-1H-diazirene-3-amine; (2) nitrogen elimination with production of 1-methyl-1H-diazirene-3-amine; and (3) ring cleavage leading to production of methyl azide and cyanamide. Following the primary photoproducts, secondary reactions were observed, leading to spectroscopic observation of methylenimine and isocyanic acid