title: Iminopropadienones RN=C=C=C=O and bisiminopropadienes RN=C=C=C=NR: matrix infrared spectra and anharmonic frequency calculations.
abstract: Methyliminopropadienone MeN=C=C=C=O 1a was generated by flash vacuum thermolysis from four different precursors and isolated in solid argon. The matrix-isolation infrared spectrum is dominated by unusually strong anharmonic effects resulting in complex fine structure of the absorptions due to the NCCCO moiety in the 2200 cm(-1) region. Doubling and tripling of the corresponding absorption bands are observed for phenyliminopropadienone PhN=C=C=C=O 1b and bis(phenylimino)propadiene PhN=C=C=C=NPh 9, respectively. Anharmonic vibrational frequency calculations allow the identification of a number of overtones and combination bands as the cause of the splittings for each molecule. This method constitutes an important tool for the characterization of reactive intermediates and unusual molecules by matrix-isolation infrared spectroscopy.
authors.affiliation: Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, Equipe Chimie Physique, UMR 5254, Université de Pau et des Pays de l'Adour, 64000 Pau, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Bégué
authors.forename: Isabelle
authors.initials: I
authors.lastname: Baraille
authors.forename: Heidi Gade
authors.initials: HG
authors.lastname: Andersen
authors.forename: Curt
authors.initials: C
authors.lastname: Wentrup