四角锥形结构化合物BeB4X4(X=H，F，Cl)，HBB4H4与BB4H4+中B4平面环的半芳香性

选用6-311++G(3df,2p)基组,在二级微扰的理论下,对四角锥形结构化合物BeB4X4(X=H,F,Cl),HBB4H4与BB4H4+的分子振动频率,及原子间的相互作用进行了计算,作用能的计算使用了CCSD(T)方法。结果显示HBB4H4与BB4H4+是违反韦德规则的另两个特例,它们表现稳定的原因与芳香性有关。

One Kind of B4 Plane Ring in the Square Pyramidal Clusters BeB4X4(X=H, F, Cl), HBB4H4 and BB4H4+ with Special Half Aromaticity

Using the 6-311++G(3df,2p) basis set, the clusters BeB₄X₄(X=H, F, Cl), HBB₄H₄ and BB₄H₄⁺ which all have a square pyramidal shape were got at the second-order Mller-Plesset perturbation (MP2) level with all frequencies real. The vertexes of these square pyramidal clusters are Be, BH and B separately. They all act as a two electron donor for B₄X₄, and the B₄X₄ act as a bowl to accommodate the pair of electrons. The interaction energies between the vertexes and the B₄X₄ bowls were calculated at the CCSD(T) level. The interactions between bowls with different terminal atoms and transferred electrons were discussed. The character of the B₄ ring is affected deeply with the terminal atoms. For HBB₄H₄ and BB₄H₄⁺, they are four and six electrons short of the Wade magic electron count, but they all have their strong bonding here.