Gas-phase flash reactions of diborane, triborane carbonyl and tetraborane with alkynes

Several known volatile closo-carboranes (1,5-C2B3HS5 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 reaction s 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 fla sh reactions. All carboranes found in these high-energy reactions are the m ost thermally stable isomers of their class. The non-isolable borane (B3H7) is suggested as the initiator in all thermal flash reactions reported here .