Paper

Dalton Trans., 2005, 1310 – 1318, DOI: 10.1039/b418276f

Gas-phase electron diffraction studies of the icosahedral carbaboranes, ortho-, meta– and para-C₂B₁₀H₁₂

Andrew R. Turner, Heather E. Robertson, Konstantin B. Borisenko, David W. H. Rankin and Mark A. Fox

The molecular structures of the three closo-carbaboranes, ortho-, meta– and para-C₂B₁₀H₁₂, were experimentally determined using gas-phase electron diffraction (GED). All unique bond distances for ortho and meta carbaboranes were determined experimentally for the first time. For ortho-carbaborane (R_G= 0.046), a model with C_2v symmetry refined to give bond distances of 1.624(8) for C–C, 1.093(8) for C–H and 1.192(3)–1.196(3) for B–H. For meta-carbaborane (R_G= 0.040) a model with C_2v symmetry refined to give a CC distance of 2.575(9). For para-carbaborane (R_G= 0.062) a model with D_5d symmetry refined to give a C–B bond distance of 1.698(3), B(2)–B(3) of 1.785(1), B(2)–B(7) of 1.774(4) and CC of 3.029(5). These GED structures are compared with geometries from other experimental diffraction methods (neutron, X-ray) and ab initio calculations.

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