Chemistry of mangana- and rhenatricarbadecaboranyl tricarbonyl complexes: evidence for an associative mechanism of ligand substitution involving an eta6-eta4 cage-slippage process analagous to eta5-eta3-cyclopentadienyl ring-slippage.

The reaction of the tricarbadecaboranyl anion, 6-Ph-nido-5,6,9-C(3)B(7)H(9)(-), with M(CO)(5)Br [M = Mn, Re] or [(eta(6)-C(10)H(8))Mn(CO)(3)(+)]BF(4)(-) yielded the half-sandwich metallatricarbadecaboranyl analogues of (eta(5)-C(5)H(5))M(CO)(3) [M = Mn, Re]. For both 1,1,1-(CO)(3)-2-Ph-closo-1,2,3,4-MC(3)B(7)H(9) [M = Mn (2) and Re (3)], the metal is eta(6)-coordinated to the puckered six-membered open face of the tricarbadecaboranyl cage. Reactions of 2 and 3 with isocyanide at room temperature produced complexes 8-(CNBu(t))-8,8,8-(CO)(3)-9-Ph-nido-8,7,9,10-MC(3)B(7)H(9) [M = Mn (4), Re (5)], having the cage eta(4)-coordinated to the metal.

Amineborane-based chemical hydrogen storage: enhanced ammonia borane dehydrogenation in ionic liquids.

Ionic liquids are shown to provide advantageous media for amineborane-based chemical hydrogen storage systems. Both the extent and rate of hydrogen release from ammonia borane dehydrogenation are significantly increased at 85, 90, and 95 degrees C when the reactions are carried out in 1-butyl-3-methylimidazolium chloride compared to analogous solid-state reactions. NMR studies in conjunction with DFT/GIAO chemical shift calculations indicate that both polyaminoborane and the diammoniate of diborane, [(NH3)2BH2+]BH4-, are initial products in the reactions.