Collect. Czech. Chem. Commun. 1999, 64, 806-818

Gas-Phase Flash Reactions of Diborane, Triborane Carbonyl and Tetraborane with Alkynes

Mark A. Fox, Robert Greatrex*, Norman N. Greenwood and Martin Kirk

School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K


Several known volatile closo-carboranes (1,5-C2B3H5, 1,6-C2B4H6, 2,4-C2B5H7, 1,10-C2B8H10) and their alkyl derivatives and ten new alkyl derivatives of these carboranes were identified from the thermal gas-phase flash reactions of B2H6, B3H7CO and B4H10 with ethyne, propyne and but-2-yne. In addition, nido-C4B2H6 and its methyl derivatives were obtained from B2H6-alkyne flash reactions. All carboranes found in these high-energy reactions are the most thermally stable isomers of their class. The non-isolable borane {B3H7} is suggested as the initiator in all thermal flash reactions reported here.

Keywords: Boranes; Carboranes; Alkynes; Gas-phase reactions; Flash reactions.