Institue of Molecular Science, Shanxi University, Taiyuan, 030001 Shanxi, People's Republic of China.
J Mol Model. 2012 Jul;18(7):3161-7. doi: 10.1007/s00894-011-1322-y. Epub 2012 Jan 10.
Based upon extensive density functional theory and wave function theory calculations performed in this work, we predict the existence of the perfectly planar triangle C(3h) B(6)H(3)(+) (1, (1)A') and the double-chain stripe C(2h) B(8)H(2) (9, (1)A(g)) which are the ground states of the systems and the inorganic analogues of cyclopropene cation D(3h) C(3)H (3) (+) and cyclobutadiene D(2h) C(4)H(4), respectively. Detailed adaptive natural density partitioning (AdNDP) analyses indicate that C(3h) B(6)H (3) (+) is π plus σ doubly aromatic with two delocalized π-electrons and six delocalized σ-electrons formally conforming to the 4n + 2 aromatic rule, while C(2h) B(8)H(2) is π antiaromatic and σ aromatic with four delocalized π-electrons and ten delocalized σ-electrons. The perfectly planar C(2h) B(8)H(4) (5, (1)A(g)) also proves to be π antiaromatic analogous to D(2h) C(4)H(4), but it appears to be a local minimum about 50 kJ mol(-1) less stable than the three dimensional C(s) B(8)H(4)(6, (1)A'). AdNDP, nucleus independent chemical shifts (NICS) and electron localization function (ELF) analyses indicate that these boron hydride clusters form islands of both σ- and π-aromaticities and are overall aromatic in nature in ELF aromatic criteria.
基于本工作中进行的广泛密度泛函理论和波函数理论计算，我们预测了完美平面三角形 C(3h)B(6)H(3)(+)（1，(1)A'）和双链条纹 C(2h)B(8)H(2)（9，(1)A(g)）的存在，它们分别是体系的基态和环丙烯阳离子 D(3h)C(3)H(3)(+)和环丁二烯 D(2h)C(4)H(4)的无机类似物。详细的自适应自然密度分区（AdNDP）分析表明，C(3h)B(6)H(3)(+) 是 π+σ 双重芳香的，具有两个离域的 π 电子和六个离域的 σ 电子，正式符合 4n+2 芳香规则，而 C(2h)B(8)H(2) 是 π 反芳香的，σ 芳香的，具有四个离域的 π 电子和十个离域的 σ 电子。完美平面的 C(2h)B(8)H(4)（5，(1)A(g)）也被证明与 D(2h)C(4)H(4)类似，是 π 反芳香的，但它似乎是一个局部极小值，比三维 C(s)B(8)H(4)(6，(1)A')低约 50 kJ mol(-1)。AdNDP、核独立化学位移（NICS）和电子定域函数（ELF）分析表明，这些硼氢化物团簇形成了 σ-和 π-芳香性的岛屿，在 ELF 芳香性标准中，整体上具有芳香性。
