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.
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.
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DOI：
10.1021/acs.inorgchem.5b02102
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发表时间：
2015-12
影响因子：
4.6
通讯作者：
Y. Vishnevskiy;D. Tikhonov;C. Reuter;N. Mitzel;D. Hnyk;J. Holub;D. Wann;P. D. Lane;R. J. Berger;Stuart A. Hayes
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文献类型：
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作者：
Y. Vishnevskiy;D. Tikhonov;C. Reuter;N. Mitzel;D. Hnyk;J. Holub;D. Wann;P. D. Lane;R. J. Berger;Stuart A. Hayes
由于碳和硼的电子散射能力相当，C2 v对称分子closo-1，2-C2 B10 H12（1）的电子衍射结构，硼簇化学的构建块之一，并不像它可能的那样准确。在此基础上，我们制备了已知的1，9，1,2-I2-closo-1，2-C2 B10 H10（2）的二碘衍生物，其具有与1相同的点群对称性，但其中碘原子的存在，其更强的散射电子的能力，确保了C2 B10二十面体核的更好的结构表征。此外，C2 B10的几何形状的影响在2 antipodally定位碘取代基相对于两个碳原子已检查使用气体电子衍射和量子化学计算在MP2和密度泛函理论（DFT）水平的协调应用。实验和计算的分子几何形状总体上一致。分子动力学模拟用于获得振动参数，这是需要分析的电子衍射数据，已进行了第一次为这类化合物。根据ZORA-SO/BP 86水平的DFT计算，碘取代基所键合的硼原子的（11）B化学位移由自旋轨道耦合支配。计算了2内的磁感应电流，并与[B_（12）H_（12）]（2-）的磁感应电流进行了比较，后者采用了具有Ih点群对称性的正二十面体结构。发现类似的总电流强度，但具有一定的各向异性，这表明存在球形芳香性;与[B12 H12]（2-）相比，2中杂原子平面中的电子离域略有阻碍，可能是因为偏离了理想的二十面体对称性。
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.