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采用B3LYP/6-311++G(d,p)方法,对环体聚硅氧烷D4H进行了量子化学研究。优化了D4H的几何构型,研究了目标化合物在几何结构、电子结构、偶极距、前线轨道等方面的性质。结果表明,D4H分子中Si-O八元环采取“椅式-船式”低能构象。Si原子上集中了大部分的正电荷,而O、C原子则带负电荷。各原子对分子HOMO、LUMO贡献的区别并不明显,HOMO、LUMO能量差较大,表明分子具有一定的稳定性。溶剂效应分析表明,随着溶剂极性的增加,分子的能量越来越小,稳定性增加。
The cyclic polysiloxane D4H was investigated by B3LYP / 6-311 ++ G (d, p) method. The geometry of D4H was optimized and the properties of the target compound in geometry, electronic structure, dipole moment and frontier orbit were studied. The results show that the Si-O eight-membered ring in D4H molecule adopts the “chair-boat” low-energy conformation. Si atoms concentrate most of the positive charge, while O and C atoms are negatively charged. The contribution of each atom to HOMO and LUMO is not obvious, and the energy difference between HOMO and LUMO is larger, indicating that the molecule has certain stability. Solvent effect analysis shows that as the solvent polarity increases, the energy of the molecules gets smaller and smaller, and the stability increases.