Facile two-electron reduction of a closo-rhodathiadecaborane.

Closo-to-arachno redox flexibility in metallaheteroboranes may be viewed as a metal-to-ligand cooperative action with application in catalysis. The treatment of [PSH][arachno-4-SB(8)H(11)] with [RhCl(PPh(3))(3)] affords, after chromatography, three new 10-vertex rhodathiaboranes, [2,2,2-(H)(PPh(3))(2)-closo-2,1-RhSB(8)H(8)] (3), [6,6,9-(PPh(3))(3)-arachno-6,5-RhSB(8)H(9)] (4) and [2,2,2-(Cl)(H)(PPh(3))-6-(PPh(3))-closo-2,1-RhSB(8)H(7)] (5). 3 reacts quantitatively with PPh(3) to form 4, which, in turn, reacts with chlorinated solvents to give the chloro-ligated cluster 5.

Ligand-controlled regioselectivity in the hydrothiolation of alkynes by rhodium N-heterocyclic carbene catalysts.

Rh-N-heterocyclic carbene compounds [Rh(μ-Cl)(IPr)(η(2)-olefin)](2) and RhCl(IPr)(py)(η(2)-olefin) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-carbene, py = pyridine, olefin = cyclooctene or ethylene) are highly active catalysts for alkyne hydrothiolation under mild conditions. A regioselectivity switch from linear to 1-substituted vinyl sulfides was observed when mononuclear RhCl(IPr)(py)(η(2)-olefin) catalysts were used instead of dinuclear precursors. A complex interplay between electronic and steric effects exerted by IPr, pyridine, and hydride ligands accounts for the observed regioselectivity.

Adducts of the supraicosahedral stannacarborane 1,6-Me2-4,1,6-closo-SnC2B10H10; synthetic, structural and computational studies.

The 13-vertex stannacarborane 1,6-Me(2)-4,1,6-closo-SnC(2)B(10)H(10) reacts with the Lewis bases 2,2'-bipyridine, 1,10-phenanthroline, 4,4'-dimethybipyridine and 4,4'-diphenylbipyridine, in toluene, to precipitate bright-yellow adducts 1,6-Me(2)-4-(L(2))-4,1,6-closo-SnC(2)B(10)H(10) (, respectively) in good yield. Compounds have been characterised by NMR spectroscopy and single-crystal X-ray diffraction. Compound is somewhat less stable in solution but has also been studied crystallographically.