Holub Josef, Vishnevskiy Yury V, Fanfrlík Jindřich, Mitzel Norbert W, Tikhonov Denis, Schwabedissen Jan, McKee Michael L, Hnyk Drahomír
Institute of Inorganic Chemistry of the Czech Academy of Sciences, CZ-250 68, Husinec - Řež, Czech Republic.
Universität Bielefeld, Fakultät für Chemie, Anorganische Chemie und Strukturchemie, Universitätsstraße 25, 33615, Bielefeld, Germany.
Chempluschem. 2020 Dec;85(12):2606-2610. doi: 10.1002/cplu.202000543. Epub 2020 Oct 7.
9-Br-closo-1,2-C B H has been prepared and its gas-phase structure has been examined by means of gas electron diffraction. The structure of the carbaborane core is similar to the structure of the parent compound, which is of C symmetry. A DFT-based search for the corresponding reaction pathway of the bromination of closo-1,2-C B H revealed that the catalytic amount of aluminum reduces the barrier of the initial attack of the bromination agent toward the negatively charged part of the icosahedral carbaborane, i. e., the first transition state, from about 40 to about 27 kcalmol . The Br-Br bond is weakened by an intermediate binding to the large π-hole on the aluminum atom of AlBr , which is the driving force for the AlBr -catalyzed bromination.
9-溴-闭式-1,2-C₂B₁₀H₁₀已被制备出来，并通过气体电子衍射对其气相结构进行了研究。碳硼烷核的结构与母体化合物的结构相似，具有C₂对称性。基于密度泛函理论（DFT）对闭式-1,2-C₂B₁₀H₁₀溴化反应相应反应途径的研究表明，催化量的铝将溴化剂对二十面体碳硼烷带负电荷部分（即第一个过渡态）的初始进攻能垒从约40 kcal/mol降低至约27 kcal/mol。Br-Br键通过与AlBr₃中铝原子上的大π空穴的中间结合而被削弱，这是AlBr₃催化溴化反应的驱动力。
