In this article, the geometrical and electronic structures of a series of borepin and beryllepin transition-metal sandwich complexes M(C₆H₆R)₂ (R = BH, Be; M = Cr, Mo, W) have been systematically investigated at the B3LYP and BP86 levels of theory. Comparing to Cr(C₆H₆)₂, the optimized structures possess the relatively larger binding energies, similar HOMO-LUMO and fundamental gaps. The topology parameters and energy decomposition analyses show the M-C₆H₆R bonding interactions are mostly covalent bonds. The detailed molecular orbital and Adaptive Natural Density Partitioning analyses indicate that the spd-π interaction plays an important role in stabilizing M(C₆H₆R)₂. Nucleus independent chemical shift (NICS) analysis indicates the aromaticity of the C₆H₇B/C₆H₆Be ligands is strengthened by the metal atoms in the sandwich complexes M(C₆H₆R)₂. Based on the negative free energy changes of the reactions of the C₆H₇B/C₆H₆Be ligands with M(C₆H₆)₂, the concerned borepin and beryllepin sandwich complexes probably are synthesized in gas phases.

在本文中，已系统地研究了一系列销钉和铍基过渡金属夹心复合物M（C ₆ H ₆ R）₂（R = BH，Be; M = Cr，Mo，W）的几何和电子结构B3LYP和BP86水平的理论。与Cr（C ₆ H ₆）_2相比，优化后的结构具有相对较大的结合能，相似的HOMO-LUMO和基本能隙。拓扑参数和能量分解分析显示MC ₆ H ₆R键相互作用主要是共价键。详细的分子轨道和自适应自然密度分配分析表明，spd-π相互作用在稳定M（C ₆ H ₆ R）_2中起着重要作用。核独立化学位移（NICS）分析表明，夹心复合物M（C ₆ H ₆ R）_2中的金属原子增强了C ₆ H ₇ B / C ₆ H ₆ Be配体的芳香性。基于C ₆ H ₇ B / C ₆ H ₆反应的负自由能变化作为具有M（C ₆ H ₆）_2的配体，有关的硼异戊烯和贝瑞林三明治复合物可能是在气相中合成的。