在B3LYP/6-31++G**水平下,对氧化呋咱单体及二聚体进行了几何构型优化,发现在由单体结合形成二聚体的过程中,子分子的平面构型并没有发生改变。通过振动频率分析结果推测出,分子中形成较大的π-π共轭,对C-H键的振动频率有影响,使得C-H...在B3LYP/6-31++G**水平下,对氧化呋咱单体及二聚体进行了几何构型优化,发现在由单体结合形成二聚体的过程中,子分子的平面构型并没有发生改变。通过振动频率分析结果推测出,分子中形成较大的π-π共轭,对C-H键的振动频率有影响,使得C-H伸缩频率发生了略微的红移,强度也明显增强。分子中原子(atoms in molecular,AIM)理论得出C-H共价键键临界点处电子密度的Laplacian值■2ρ具有负值。而O…H与N…H键临界点处2ρ都是大于零的,表明氧化呋咱二聚体中的O…H与N…H符合一般氢键的拓扑特点。二聚体在C-H键临界点处聚积电子的能力增强。运用渐近修正的SAPT(DFT)方法(symmetry-adapted perturbationtheory employing density functional theory),对氧化呋咱二聚体分子间作用进行能量分割。其中二聚体的静电能分别为-30.10kJ.mol-1和-37.36kJ.mol-1,与总的作用能相当,这也从侧面反映了氧化呋咱二聚体中分子中氢键作用主要由静电能决定。展开更多
The non-additivity of the methyl groups in the single-electron lithium bond was investigated using ab initio calculations at the B3LYP/6-311＋＋G＊＊ and UMP2/6-311＋＋G＊＊ levels. The strength of the interaction in ...The non-additivity of the methyl groups in the single-electron lithium bond was investigated using ab initio calculations at the B3LYP/6-311＋＋G＊＊ and UMP2/6-311＋＋G＊＊ levels. The strength of the interaction in the H3C… LiH, H3CH2C… LiH, （H3C）2HC… LiH, and u v （H3C）3C… LiH complexes was analyzed in term of the geometries, energies, frequency shifts, stabilization energies, charges, and topological parameters. It is shown that （H3C）3C radical with LiH forms the strongest single-electron lithium bond, followed by （H3C）2HC radical, then H3CH2C radical, and H3C radical forms the weakest single-electron lithium bond. A positive non-additivity is present among methyl groups. Natural bond orbital and atoms in molecules analyses were used to estimate such conclusions. Furthermore, there are few linear/nonlinear relationships in the system and the interaction mode of single-electron Li- bond is different from the single-electron H-bond and single-electron halogen bond.展开更多
文摘在B3LYP/6-31++G**水平下,对氧化呋咱单体及二聚体进行了几何构型优化,发现在由单体结合形成二聚体的过程中,子分子的平面构型并没有发生改变。通过振动频率分析结果推测出,分子中形成较大的π-π共轭,对C-H键的振动频率有影响,使得C-H伸缩频率发生了略微的红移,强度也明显增强。分子中原子(atoms in molecular,AIM)理论得出C-H共价键键临界点处电子密度的Laplacian值■2ρ具有负值。而O…H与N…H键临界点处2ρ都是大于零的,表明氧化呋咱二聚体中的O…H与N…H符合一般氢键的拓扑特点。二聚体在C-H键临界点处聚积电子的能力增强。运用渐近修正的SAPT(DFT)方法(symmetry-adapted perturbationtheory employing density functional theory),对氧化呋咱二聚体分子间作用进行能量分割。其中二聚体的静电能分别为-30.10kJ.mol-1和-37.36kJ.mol-1,与总的作用能相当,这也从侧面反映了氧化呋咱二聚体中分子中氢键作用主要由静电能决定。
基金supported by the National Natural Science Foundation of China(20973088,21173109,21133005)Specialized Research Fund for the Doctoral Program of Higher Education of China(20102136110001)Program for Liaoning Excellent Talents in University,China(LR2012037)~~
文摘The non-additivity of the methyl groups in the single-electron lithium bond was investigated using ab initio calculations at the B3LYP/6-311＋＋G＊＊ and UMP2/6-311＋＋G＊＊ levels. The strength of the interaction in the H3C… LiH, H3CH2C… LiH, （H3C）2HC… LiH, and u v （H3C）3C… LiH complexes was analyzed in term of the geometries, energies, frequency shifts, stabilization energies, charges, and topological parameters. It is shown that （H3C）3C radical with LiH forms the strongest single-electron lithium bond, followed by （H3C）2HC radical, then H3CH2C radical, and H3C radical forms the weakest single-electron lithium bond. A positive non-additivity is present among methyl groups. Natural bond orbital and atoms in molecules analyses were used to estimate such conclusions. Furthermore, there are few linear/nonlinear relationships in the system and the interaction mode of single-electron Li- bond is different from the single-electron H-bond and single-electron halogen bond.
