title: Gas-phase infrared spectra of vinyl selenol and vinyl tellurol.
abstract: The infrared spectra (3500-500 cm(-1)) of gaseous vinyl selenol and vinyl tellurol have been recorded at 0.1 cm(-1) resolution. For the latter the spectra were obtained at room temperature, but for the former a temperature of -40 degrees C was required because of the chemical instability of vinyl selenol at room temperature. To compensate the very weak vapor pressure of vinyl tellurol at room temperature, a long optical path up to 136 m was necessary to record its spectrum. B3LYP density functional theory (DFT) calculations have been performed to assign the different absorption bands. Since an unambiguous assignment of the absorption bands requires a precise knowledge on the relative abundance of the syn and gauche rotamers of these compounds, their relative energies and their anharmonic vibrational frequencies were obtained using a very extended Def2-QZVP basis set. Two rotamers, the syn, which is planar, and a nonplanar gauche, were found to be local minima for both compounds. The gauche rotamer presents two degenerate conformers, which differ by the position of the SeH (TeH) hydrogen atom above or below the molecular plane. Our theoretical results are in good agreement with the main features of the experimental spectra. Fundamental bands and some combination bands of vinyl selenol and vinyl tellurol were assigned and compared with those of vinyl alcohol and vinyl thiol, whose spectra had been reported previously in the literature.
authors.affiliation: Institut de Physique de Rennes, Equipe Astrochimie Expérimentale UMR 6251 CNRS, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France. benidar@univ-rennes1.fr
authors.forename: Abdessamad
authors.initials: A
authors.lastname: Benidar
authors.forename: Brahim
authors.initials: B
authors.lastname: Khater
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Guillemin
authors.forename: José A
authors.initials: JA
authors.lastname: Gámez
authors.forename: Manuel
authors.initials: M
authors.lastname: Yáñez
mesh_terms: D003198:Computer Simulation; D056831:Coordination Complexes / Q000737:chemistry*; D005740:Gases / Q000737:chemistry*; D008956:Models, Chemical; D016566:Organoselenium Compounds / Q000737:chemistry*; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D014732:Vibration; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D005740:Gases; D016566:Organoselenium Compounds; D014753:Vinyl Compounds; C547007:vinyl selenol; C547008:vinyl tellurol