The structure of [PPh(3)(benzyl)][B(10)H(11)] was determined at -123 degrees C and 24 degrees C by single-crystal X-ray analyses. The B(10) core of [B(10)H(11)](-) is similar in shape to that of [B(10)H(10)](2)(-). The 11th H atom asymmetrically caps a polar face of the cluster and shows no tendency for disorder in the solid state. Variable temperature multinuclear NMR studies shed light on the dynamic nature of [B(10)H(11)](-) in solution. In addition to the fluxionality of the cluster H atoms, the boron cage is fluxional at moderate temperatures, in contrast to [B(10)H(10)](2)(-). Multiple exchange processes are believed to take place as a function of temperature. Results of ab initio calculations are presented. Crystal data: [PPh(3)(benzyl)][B(10)H(11)] at -123 degrees C, P2(1)/c, a = 9.988(2) A, b = 18.860(2) A, c = 15.072(2) A, beta = 107.916(8) degrees, V = 2701.5(7) A(3), Z = 4; [PPh(3)(benzyl)][B(10)H(11)] at 24 degrees C, P2(1)/c, a = 10.067(5) A, b = 19.009(9) A, c = 15.247(7) A, beta = 107.952(9) degrees, V = 2775(2) A(3), Z = 4.

Preceramic precursors containing Al−N−B linkages were produced from the reactions of Me3NAlH3 with NH3BH3 in 1:1 and 1:2 ratios in toluene solutions followed by treatment with liquid ammonia. Both precursors were transformed into intimate ceramic mixtures of AlN and BN via pyrolysis under NH3 at 1000 °C. The AlN/BN ceramic composites were characterized by IR, XRD, and solid-state 27Al and 11B MAS NMR spectroscopies. SEM studies revealed that they were composed of nanosized composite particles of AlN and BN.

A yellow, solid, ion-dipole charge transfer complex, [M][B10H14I], is formed upon mixing the solids [M]I (M = [N(n-(C4H9)(4)](+), [P(C6H5)(3)CH3](+), [(Ph(3)P)(2)N](+)) and B10H14. The [B10H14I](-) ion is stabilized in the solid state by the presence of bulky cations; B10H14 cannot be separated by sublimation from the solid. A Job continuous variations experiment establishes that the reaction stoichiometry, a 1:1 molar ratio of [N(n-(C4H9)(4)]I to B10H14, also occurs in CH2Cl2 solution. While there is no apparent reaction when solid alkali metal iodides are mixed with B10H14 in the absence of a solvent, addition of an appropriate solvent to the solid mixture causes formation of the [B10H14I](-) anion. However, removal of the solvent causes the complex to revert to a mixture from which B10H14 can be removed by sublimation. When 2,4-I2B10H12 is mixed with iodide salts of the cations [N(n-C4H9)(4)](+) [P(C6H5)(3)CH3](+), [(Ph(3)P)(2)N](+), Na+, and K+ in the absence of a solvent, there is no apparent reaction. However when a suitable solvent is present, the complex anion [2,4-I2B10H12I](-) is formed. A single crystal X-ray structure determination of [P(C6H5)(3)CH3][2,4-I2B10H12I] shows the unique iodide residing on top of the four hydrogen bridge atoms and the 6,9 boron atoms at the opening of the B-10 basket. Crystal data for [P(C6H5)(3)CH3][2,4-I2B10H12I]: monoclinic P2(1)/c, a = 12.868(4) Angstrom, b = 10.562(3) Angstrom, c = 22.007(8) Angstrom, beta = 99.40(2)degrees, Z = 4, V = 2950.7 Angstrom(3), R = 3.3%, R(w) = 3.6%.