平面型四核铜簇合物Cu_4(CH_2XMe_n)_4桥键性质的密度泛函研究

Density functional studies on bridge bond properties of square-planar tetranuclear copper clusters Cu_4(CH_2XMe_n)_4

采用密度泛函B3LYP方法,用LanL2DZ和6 31G*基组分别优化了平面型四核铜簇合物Cu4(CH2SiMe3)4和Cu4(CH2XMe2)4(X=P,As)的几何构型,并对B3LYP/LanL2DZ方法优化的结构进行了红外振动频率计算和自然键轨道分析.结果表明,簇合物均呈笼状结构,Cu-C-Cu三中心桥键之间电子的离域增强了Cu簇合物的稳定性,配位C原子的C-H平伏键与C-Cu配位键之间存在σ超共轭效应.

The geometries of Cu4 （CHz SiMe3 ）4 and Cu4 （CH2 XMe2 ）4 （X = P, As） have been calculated by using density function method B3LYP with LanL2DZ and 6 - 31G^＊ basis set as well as IR vibrational frequencies and natural bond orbital analyses for their optimized geometries by B3LYP method with LanL2DZ basis set. The results show that each of the clusters is shaped like a cage. The eight - membered ring that is composed of the three - centre bridge bonds is delocalized, which plays a great role of stability in cluster. The σ - hyperconjugation is found between the C--H equatorial bonds of coordi- nate carbon atoms and C--Cu coordinate bonds.