Gas-Phase Electron Diffraction Studies on Two 11-Vertex Dicarbaboranes,closo-2,3-C2B9H11andnido-2,9-C2B9H13

Abstract
The molecular structures of two carbaboranes, closo-2,3-C2B9H11 and nido-2,9-C2B9H13, were determined experimentally for the first time using gas-phase electron diffraction (GED). For closo-2,3-C2B9H11, a model with C2v symmetry was refined to give C−B bond distances ranging 158.3−167.0 pm and B−B distances ranging 177.4−200.0 pm. The structure of nido-2,9-C2B9H13 was refined using a model with Cs symmetry to give C−B bond lengths ranging 160.3−171.9 pm and B−B lengths ranging 173.0−196.1 pm. Ab initio computations (up to MP2/6-311+G*) were also carried out on these and the related nido-7,8-C2B9H13, which was not sufficiently stable to allow determination of its molecular structure by GED.