内含式化合物X@B12P12的结构与稳定性研究

采用B3LYP/6-31G*方法，对内含式化合物X@B₁₂P₁₂(X=Li^0/+、Na^0/+、K^0/+、Be^0/2+、Mg^0/2+、Ca^0/2+、H和He)的不同对称性构型进行了计算，讨论其最稳定构型的几何参数、布居分析、偶极矩、电离势、包含能、振动频率、能隙和自旋密度． 发现在X@B₁₂P₁₂化合物中，客体X=Li、Na^0/+、K^0/+、Mg^0/2+、Ca^0/2+和He处在偏离笼的中心0.006 nm的半径内． Be²⁺沿着C₃轴偏离中心点0.279 nm． 在Be@B₁₂P₁₂和H@B₁₂P₁₂的基态结构中，Be和H与笼上的B原子成键． 除Li@B₁₂P₁₂、 Be²⁺@B₁₂P₁₂和He@ B₁₂P₁₂外， 其余结构为C_s对称稳定构型．

Structure and Stability of Endohedral Complexes X@B12P12

All structures of X@B12P12 (X=Li0/ ,Na0/ ,K0/ ,Be0/2 ,Mg0/2 ,Ca0/2 ,H and He) are optimized at the B3LYP/6-31G density functional level of theory, and the corresponding frequency calculations at the same level are used to characterize the optimized structures with energy minima without imaginary frequencies. The geometries,natural bond orbitals (NBO), dipole moments, adiabatic ionization potentials, inclusion energies, vibrational frequencies, energy gaps and spin densities are also discussed. The calculations predict that X= Li, Na0/ , K0/ ,Mg0/2 ,Ca0/2 and He are in the vicinity of 0.006 nm of the cage center, and Be2 is displaced by 0.279 nm from the cage center along the threefold axis of B12P12. Be@B12P12 and H@B12P12 have endohedral Be-B and H-B bonds respectively. Except for Li@B12P12, Be2 @B12P12, and He@B12P12, all conformations favor Cs symmetry.