Pentahapto-bonded gold heteroborane clusters [3-(R3P)-closo-2,1-AuTeB10H10]- and [3-(R3P)-closo-3,1,2-AuAs2B9H9]-.

Gold acetylide compounds [(R3P)AuC[triple bond]CC(Me)(OH)Et], where R = Ph 1 or cyclohexyl (Cy) 2, were synthesised and 2 was characterised using X-ray diffraction techniques. The solid-state structure of 2 contained a two-coordinate gold atom and a linear P-Au-C[triple bond]C-C bonding sequence. The reactions between 1 or 2 and [NR4][nido-7,8-As2B9H10] or [NR4][nido-7-TeB10H10] in ethanol-acetone solvent afforded the twelve-vertex cluster species [NMe4][3-(R3P)-closo-3,1,2-AuAs2B9H9], where R = Ph 5 or Cy 6, or [NEt4][3-(R3P)-closo-2,1-AuTeB10H10], where R = Ph 7 or Cy 8, in moderate or low yields (ca.

Twisted [(R(3)P)PdX] groups above dicarbaborane ligands: 4-dimethylsulfido-3-iodo-3-triphenylphosphine-closo-3-pallada-1,2-dicarbadodecaborane and 3-dimethylphenylphosphine-3-chloro-4-dimethylsulfido-closo-3-pallada-1,2-dicarbadodecaborane.

The structural analyses of [3-(PPh3)-3-I-4-(SMe2)-closo-3,1,2-PdC2B9H10] or [Pd(C4H16B9S)I(C18H15P)], (I), and [3-(PPhMe2)-3-Cl-4-(SMe2)-closo-3,1,2-PdC2B9H10] or [Pd(C4H16B9S)Cl(C8H11P)], (II), show that in comparison with [3-(PR3)2-closo-3,1,2-PdC2B9H11] the presence of the 4-SMe2 group causes the [PdX(PR3)] unit (X = halogen) to twist about an axis passing through the Pd atom and the directly opposite B atom of the carbaborane ligand. The halogen atoms are located almost directly above a C atom in the C2B3 face, and the conformations of the [PdX(PR3)] units above the C2B3 faces are not those predicted from molecular orbital calculations of the closo-3,1,2-PdC2B9 system. The fact that the variation from the predicted conformation is greater in the case of (I) than in (II) may be ascribed to the greater steric interactions induced by the I atom in (I) compared with the Cl atom in (II).

Coordination and cluster compounds of ruthenium with the [hypho-1,2-S2B6H9]- ligand.

The reaction between [tmndH][hypho-1,2-S(2)B6H9](tmnd =N,N,N',N'-tetramethylnaphthalene-1,8-diamine) and [RuCl(PPh3)2(eta5-Cp)] in CH2Cl2 at room temperature afforded two ruthenathiaboranes, [5-(eta(5)-Cp)-5-(PPh3)-5,4,6-RuS2B6H9], 1, and [Ru(eta(1)-1,2-S2B6H9)(PPh3)2(eta5-Cp)], 2, in 6 and 48% yields, respectively. The heating of a solution of [Ru(eta(1)-1,2-S2B6H9)(PPh3)2(eta5-Cp)] 2 in CH2Cl2 at reflux temperature afforded 1 in 59% yield. Compound 1 could be described as either a hypho nine-vertex {RuS2B6} cluster or a coordination compound of ruthenium which contains a bidentate eta2-dithiaborate cluster ligand; the latter description is preferred.

Pore size engineering in mesoporous silicas using supercritical CO2.

In this paper we investigate the use of supercritical carbon dioxide (sc-CO(2)) for synthesizing calcined mesoporous silicas with tunable pore sizes, wall thickness, and d spacings. Small angle neutron scattering was used to probe the controlled swelling of the triblock copolymer surfactant templating agents, P123 (PEO(20)PPO(69)PEO(20)), P85 (PEO(26)PPO(39)PEO(26)), and F127 (PEO(106)PPO(70)PEO(106)), as a function of CO(2) pressure. The transition from the liquid crystal phase to the calcined mesoporous silicas, formed upon condensation and drying, was also studied in detail.

The synthesis of matrices of embedded semiconducting nanowires.

In this work we report how single crystal nanowires can be assembled into regular arrays using mesoporous thin films to define the architecture. Mesoporous thin films were prepared by a sol-gel method. These provide films of very regular structure and dimensions.

Structural chemistry of arachno-nonaboranes.

Single-crystal conventional-tube and synchrotron X-ray diffraction studies of the anions in [NMe(4)][arachno-B(9)H(12)-4,8-Br(2)] 1 and K[arachno-B(9)H(14)] 2, and also of the series of adducts [arachno-B(9)H(13)-4-L], where L is P(CCH)(3) (3), NHEt(2) (4), NC(5)H(5) (5), or NH(2)CH(2)Ph (6), are reported. Structural studies of 1-6, determined at low temperatures, located all atoms, including bridging and endo-terminal hydrogen atoms. The basic boron-hydride clusters of these, and of all the other known species with the arachno nine-vertex i-nonanborane geometry reported in the literature, are isostructural and feature three bridging and two endo-terminal hydrogen atoms on the open face.