Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
Faculty of Chemical Technology, University of Pardubice, CZ-532 10 Pardubice, Czech Republic.
Molecules. 2023 Apr 21;28(8):3645. doi: 10.3390/molecules28083645.
Modern computational protocols based on the density functional theory (DFT) infer that polyhedral ten-vertex carboranes are key starting stationary states in obtaining ten-vertex cationic carboranes. The rearrangement of the bicapped square polyhedra into decaborane-like shapes with open hexagons in boat conformations is caused by attacks of N-heterocyclic carbenes (NHCs) on the motifs. Single-point computations on the stationary points found during computational examinations of the reaction pathways have clearly shown that taking the "experimental" NHCs into account requires the use of dispersion correction. Further examination has revealed that for the purposes of the description of reaction pathways in their entirety, i.e., together with all transition states and intermediates, a simplified model of NHCs is sufficient. Many of such transition states resemble in their shapes those that dictate -rearrangement among various isomers of ten-vertex carboranes. Computational results are in very good agreement with the experimental findings obtained earlier.
基于密度泛函理论(DFT)的现代计算方案推断,多面体十顶点碳硼烷是获得十顶点阳离子碳硼烷的关键起始稳定态。双帽四方多面体通过 N-杂环卡宾(NHC)对骨架的攻击,重排成具有船式构象的开六元环的类十硼烷形状。对反应途径计算研究中发现的稳定点进行单点计算,清楚地表明,考虑“实验”NHC 需要使用色散校正。进一步的研究表明,为了完整地描述反应途径,即包括所有过渡态和中间体,简化的 NHC 模型就足够了。许多这样的过渡态在形状上类似于决定各种十顶点碳硼烷异构体之间重排的过渡态。计算结果与之前获得的实验结果非常吻合。