title: A combined crossed molecular beams and ab initio investigation on the formation of vinylsulfidoboron (C₂H₃¹¹B³²S).
abstract: We exploited crossed molecular beams techniques and electronic structure calculations to provide compelling evidence that the vinylsulfidoboron molecule (C2H3(11)B(32)S) - the simplest member of hitherto elusive olefinic organo-sulfidoboron molecules (RBS) - can be formed via the gas phase reaction of boron monosulfide ((11)B(32)S) with ethylene (C2H4) under single collision conditions. The reaction mechanism follows indirect scattering dynamics via a barrierless addition of the boron monosulfide radical to the carbon-carbon double bond of ethylene. The initial reaction complex can either decompose to vinylsulfidoboron (C2H3(11)B(32)S) via the emission of a hydrogen atom from the sp(3) hybridized carbon atom, or isomerize via a 1,2-hydrogen shift prior to a hydrogen loss from the terminal carbon atom to form vinylsulfidoboron. Statistical (RRKM) calculations predict branching ratios of 8% and 92% for both pathways leading to vinylsulfidoboron, respectively. A comparison between the boron monosulfide ((11)B(32)S) plus ethylene and the boron monoxide ((11)BO) plus ethylene systems indicates that both reactions follow similar reaction mechanisms involving addition - elimination and addition - hydrogen migration - elimination pathways. Our experimental findings open up a novel pathway to access the previously poorly-characterized class of organo-sulfidoboron molecules via bimolecular gas phase reactions, which are difficult to form through 'classical' organic synthesis.
authors.affiliation: Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA. ralfk@hawaii.edu.
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Beni B
authors.initials: BB
authors.lastname: Dangi
authors.forename: Dorian S N
authors.initials: DS
authors.lastname: Parker
authors.forename: Ralf I
authors.initials: RI
authors.lastname: Kaiser
authors.forename: Yi
authors.initials: Y
authors.lastname: An
authors.forename: Agnes H H
authors.initials: AH
authors.lastname: Chang