title: Methyliminopropadienone CH3-N═C═C═C═O: photoelectron spectrum and electronic structure.
abstract: N-Methyliminopropadienone MeN═C═C═C═O 1a was generated by flash vacuum thermolysis of three 5-(aminomethylene)-1,3-dioxane-4,6-diones (Meldrum's acid derivatives). Online monitoring of the reactions permitted the recording of the UV-photoelectron spectra and the determination of the first two ionization energies of 1a as 9.0 and 12.4 eV. The first ionization energy (and the calculated highest occupied molecular orbital energy) of 1a are more comparable with those of N-methylketenimine than with ketene. In contrast, the calculated lowest unoccupied molecular orbital energy is significantly lower than those of both ketene and N-methylketenimine, thereby making iminopropadienones powerful electrophiles. Calculated charge densities indicate that electrophiles should attack at C3 or O and nucleophiles at C2 or C4 in broad agreement with experimental observations.
authors.affiliation: Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, UMR CNRS 5254, Université de Pau et des Pays de l'Adour, 64 000 Pau, France. anna.chrostowska@univ-pau.fr
authors.forename: Anna
authors.initials: A
authors.lastname: Chrostowska
authors.forename: Alain
authors.initials: A
authors.lastname: Dargelos
authors.forename: Saïd
authors.initials: S
authors.lastname: Khayar
authors.forename: Curt
authors.initials: C
authors.lastname: Wentrup