New, systematic syntheses of boron hydrides via hydride ion abstraction reactions: preparation of B2H6, B4H10, B5H11, and B10H14

Recent Advances in the Chemistry of Metallacarboranes

“…[1] They are generally synthesized by the reaction of the mono-or dianions of their respective nido-C 2 B 4 or C 2 B 9 carboranes with suitable metal reagents. Much of the interest in them stems from the fact that three primary metalbinding carborane π-type molecular orbitals that are localized on the C 2 B 3 open pentagonal faces, which are quite similar to those in cyclopentadienide [C 5 R 5 ] Ϫ ligands.…”

“…However, at present, that source is no longer available, and no commercial source has taken its place. [5] Thus, a new, convenient and safe method of producing pentaborane (9) is needed Ϫ ideally a one-pot method from a readily available starting material so that the pentaborane (9) can then further react with the appropriate alkyne to generate, in situ, the corresponding small-cage carborane; such a method is described herein. With a steady source of starting materials available, we have extended our studies of the ''carbon atoms apart'' metallacarboranes.…”

“…This is usually accomplished in the original carborane synthesis by treating substituted acetylenes with either the decaborane (14) or pentaborane (9) precursors to give directly carboranes that have adjacent carbon atoms in the cage (''carbon atoms adjacent''). The larger cages are obtained as closo-icosahedra, while the small-cage C 2 B 4 carboranes have nido structures as well as a cage geometry in which the carbon atoms are separated by a boron atom.…”

Kinetics of Boron Hydride Interconversion Reactions

“…Likewise, the self-reaction of 2(84H81 to form either B6HIO and B2H6 or B5H9 and {B3H7) are also ruled out on this basis, and their reaction to form, B5HII and 'B3H5(polymer)', for which their is good evidence in a different context (ref. 28) is unlikely to be an important route in the presence of a vastly greater concentration of B4H1O.…”

Studies on the Syntheses of Boron Hydride Systems.

“…Our earlier development of a simple, safe, and high yield synthesis of B 4 Ho has made available potentially convenient routes to metallapentaboranes through the reaction of ES 4 H ]-with suitable transition metal complexes. These possibilities have been pursued as adjuncts to our boron hydride syntheses.…”