Showing papers by "Bruce S. Ault published in 1986"

Infrared spectra and structure of the matrix-isolated 1:1 complexes of sulfur trioxide with ammonia and the methylamines

Abstract: The 1:1 molecular complexes between SO/sub 3/ and NH/sub 3/, pyridine, and the methylamines have been isolated and characterized in nitrogen matrices. All complexes are characterized by a red shift of the SO/sub 3/ antisymmetric stretching vibration typified by the 1354-cm/sup -1/ absorption of the SO/sub 3/.NH/sub 3/ complex. In addition, the perturbed symmetric and antisymmetric deformation modes of the coordinated NH/sub 3/ were observed, and assignment was confirmed by /sup 15/N labeling. The magnitude of the red shift of nu/sub 3/ of SO/sub 3/ increased with increasing basicity of the amine from 44 cm/sup -1/ for NH/sub 3/ to 68 cm/sup -1/ for trimethylamine. In addition, the activation of the SO/sub 3/ symmetric stretching mode was observed via lowering in symmetry. While the NH/sub 3/.SO/sub 3/ complex was very sensitive to annealing, the remaining complex studies were quite stable. 31 references, 2 figures, 3 tables.

Matrix isolation infrared spectra of the 1:1 molecular complexes of sulfur trioxide with selected oxygen-containing bases

Abstract: The 1:1 molecular complexes between SO/sub 3/ and a series of oxygen-containing bases have been isolated and characterized in nitrogen matrices. The spectra of the complexes all showed a red shift and splitting of the antisymmetric stretching mode of the SO/sub 3/ subunit in the complex, typified by product bands at 1362 and 1378 cm/sup -1/ in the complex with dimethyl ether. A number of perturbed vibrational modes of the base subunit were observed as well, and generally arose from vibrations involving motion of the oxygen atom of the base. A comparison of the shift of the perturbed base modes in these complexes with previously studied complexes indicated that SO/sub 3/ is a very strong Lewis acid, although only small shifts were observed for the SO/sub 3/ subunit, and the symmetric stretching mode was not activated to a detectable degree.

Infrared matrix isolation studies of the 1:1 molecular complexes of hydrogen chloride and hydrogen bromide with substituted cyclopropanes

Abstract: Caracterisation des complexes formes entre HCl ou HBr et les cyclopropanes portant un substituant electroattracteur: Br, CN, CH 2 Br, CHOHCH 3 ou COCH 3