Icosahedral Carbaboranes with Peripheral Hydrogen–Chalcogenide Groups: Structures from Gas Electron Diffraction and Chemical Shielding in Solution

Abstract

Carbaboranes 1,2‐(EH)2‐closo‐1,2‐C2B10H10 (E=S, Se) were prepared, in the case of E=Se for the first time. Their semi‐experimental equilibrium molecular structures were established by the concerted use of quantum‐chemical calculations and gas electron diffraction. A method was developed and implemented to quantify the contribution of experimental data to each refined structural parameter. The accuracy of the experimental structures and those calculated at the MP2 level of theory were gauged by comparison of experimental 11B NMR chemical shifts with quantum‐chemically computed values; the inclusion of electron correlation (GIAO‐MP2) provided superior results. For the purpose of geometrical prediction, the remaining group 16 elements were considered, and the icosahedral structures for E=O and Te were also computed; for E=O the same theoretical approach was used as for E=S, and for E=Te a description similar to that for E=Se was employed.

Solid‐State and Gas‐Phase Structures and Energetic Properties of the Dangerous Methyl and Fluoromethyl Nitrates

“…In parentheses are total standard deviations obtained from Monte Carlo simulations as described earlier . [b] Contribution of GED data to refined value, estimated according to the W2 method . [c] Weighted root‐mean‐square deviation of model rotational constants from experimental.…”

Festkörper‐ und Gasphasenstrukturen sowie energetische Eigenschaften des gefährlichen Methyl‐ und Fluormethylnitrats

“…In Klammern sind die mit der Monte‐Carlo‐Methode berechneten Gesamtstandardabweichungen angegeben. [b] Beitrag der GED‐Daten zu den verfeinerten Werten, geschätzt nach der Methode W2 . [c] Gewichtete Wurzel aus dem mittleren Fehlerquadrat der Abweichung der Rotationskonstanten des Modells vom Experiment.…”

Inter‐ and Intramolecular Aryl–Aryl Interactions in Partially Fluorinated Ethylenedioxy‐bridged Bisarenes**

“…The contributionso fe xperimental dataa nd regularization data, respectively,w ere calculated according to the W2 method. [39] Amplitudes of vibrations were refinedi ng roups keeping the ratios within groups fixed at theoretical values. Modelso fa ll conformers were refined in exactly the same manner with the same extents of regularization.…”