title: Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12-I2-closo-1,2-C2B10H10: An Electron Diffraction and Computational Study.
abstract: Because of the comparable electron scattering abilities of carbon and boron, the electron diffraction structure of the C2v-symmetric molecule closo-1,2-C2B10H12 (1), one of the building blocks of boron cluster chemistry, is not as accurate as it could be. On that basis, we have prepared the known diiodo derivative of 1, 9,12-I2-closo-1,2-C2B10H10 (2), which has the same point-group symmetry as 1 but in which the presence of iodine atoms, with their much stronger ability to scatter electrons, ensures much better structural characterization of the C2B10 icosahedral core. Furthermore, the influence on the C2B10 geometry in 2 of the antipodally positioned iodine substituents with respect to both carbon atoms has been examined using the concerted application of gas electron diffraction and quantum chemical calculations at the MP2 and density functional theory (DFT) levels. The experimental and computed molecular geometries are in good overall agreement. Molecular dynamics simulations used to obtain vibrational parameters, which are needed for analyzing the electron diffraction data, have been performed for the first time for this class of compound. According to DFT calculations at the ZORA-SO/BP86 level, the (11)B chemical shifts of the boron atoms to which the iodine substituents are bonded are dominated by spin-orbit coupling. Magnetically induced currents within 2 have been calculated and compared to those for [B12H12](2-), the latter adopting a regular icosahedral structure with Ih point-group symmetry. Similar total current strengths are found but with a certain anisotropy, suggesting that spherical aromaticity is present; electron delocalization in the plane of the hetero atoms in 2 is slightly hindered compared to that for [B12H12](2-), presumably because of the departure from ideal icosahedral symmetry.
authors.affiliation: Universität Bielefeld , Universitätsstraße 25, D-33615 Bielefeld, Germany.
authors.forename: Yury V
authors.initials: YV
authors.lastname: Vishnevskiy
authors.affiliation: Universität Bielefeld , Universitätsstraße 25, D-33615 Bielefeld, Germany.|M. V. Lomonosov Moscow State University , Department of Physical Chemistry, GSP-1, 1-3 Leninskiye Gory, 119991 Moscow, Russian Federation.
authors.forename: Denis S
authors.initials: DS
authors.lastname: Tikhonov
authors.affiliation: Universität Bielefeld , Universitätsstraße 25, D-33615 Bielefeld, Germany.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Reuter
authors.affiliation: Universität Bielefeld , Universitätsstraße 25, D-33615 Bielefeld, Germany.
authors.forename: Norbert W
authors.initials: NW
authors.lastname: Mitzel
authors.affiliation: Institute of Inorganic Chemistry of the ASCR , v.v.i, CZ-250 68 Husinec-Řež, Czech Republic.
authors.forename: Drahomír
authors.initials: D
authors.lastname: Hnyk
authors.affiliation: Institute of Inorganic Chemistry of the ASCR , v.v.i, CZ-250 68 Husinec-Řež, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Holub
authors.affiliation: Department of Chemistry, University of York , Heslington, York YO10 5DD, U.K.
authors.forename: Derek A
authors.initials: DA
authors.lastname: Wann
authors.affiliation: Department of Chemistry, University of York , Heslington, York YO10 5DD, U.K.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Lane
authors.affiliation: Materialchemie, Paris-Lodron Universität Salzburg , Hellbrunner Straße 34, A-5020 Salzburg, Austria.
authors.forename: Raphael J F
authors.initials: RJ
authors.lastname: Berger
authors.affiliation: Universität Bielefeld , Universitätsstraße 25, D-33615 Bielefeld, Germany.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Hayes