Institute of Molecular Science, Shanxi University, Taiyuan 030006, Shanxi, People's Republic of China.
J Chem Phys. 2013 Jun 28;138(24):244304. doi: 10.1063/1.4811330.
Inorganic benzene-like compounds such as boroxine and borazine are of interest in chemistry. Here we report on theoretical prediction of a new member of the inorganic benzene family: boronyl boroxine. This perfectly planar D3h B6O6 (1, (1)A1') cluster is identified as the global minimum of the system at density functional theory (B3LYP) and molecular orbital theory levels, which lies at least ∼20 kcal∕mol lower in energy than alternative structures. It can be formulated as B3O3(BO)3 and features a boroxol B3O3 ring as the core with three boronyl (BO) groups attached terminally, closely resembling boroxine and obtainable from the latter via isovalent BO∕H substitution. Detailed bonding analyses reveal weak π aromaticity in boronyl boroxine, rendering it a true analog to boroxine and borazine. Upon electron attachment, the slightly distorted C2v B6O6(-) (2, (2)A2) anion is also perfectly planar, and its electronic properties are calculated. A huge energy gap (4.83 eV) is predicted for B6O6(-) (2) at B3LYP level, which is characteristic of a stable closed-shell neutral cluster. Similar to benzene, boronyl boroxine is also predicted to be an effective inorganic ligand to form sandwich-type complexes, such as D3d [B3O3(BO)3]2Cr (4, (1)Ag).
无机苯类化合物，如硼氧环和硼氮环，在化学中很有研究价值。在这里，我们报告了无机苯家族的一个新成员的理论预测：硼基硼氧环。这种完全平面的 D3h B6O6（1，（1）A1'）簇在密度泛函理论（B3LYP）和分子轨道理论水平上被确定为体系的全局最小值，其能量至少比替代结构低约 20 kcal/mol。它可以表示为 B3O3（BO）3，具有硼氧环 B3O3 作为核心，三个硼基（BO）基团末端连接，与硼氧环和硼氮环非常相似，可以通过等电子 BO/H 取代从后者获得。详细的键分析表明，硼基硼氧环中存在弱π芳香性，使其成为真正的硼氧环和硼氮环类似物。在电子加成后，略微扭曲的 C2v B6O6(-)（2，（2）A2）阴离子也是完全平面的，并且计算了其电子性质。在 B3LYP 水平上，预测 B6O6(-)（2）的能隙巨大（4.83 eV），这是稳定的满壳中性簇的特征。与苯类似，硼基硼氧环也被预测为形成夹心型配合物的有效无机配体，如 D3d [B3O3（BO）3]2Cr（4，（1）Ag）。
