化学学报 ›› 2009, Vol. 67 ›› Issue (14): 1585-1590. 上一篇    下一篇

研究论文

双核钯配合物Pd2L2和Pd2L2X2 (L=Me2PCH2PMe2; X=F, Cl, Br, I, H)的量子化学理论研究

仇毅翔 李 佳 王曙光

  

  1. (上海交通大学化学化工学院 上海 200240)

  • 投稿日期:2008-09-19 修回日期:2009-02-26 发布日期:2009-07-28
  • 通讯作者: 王曙光

Quantum Chemical Theoretical Investigations on Dinuclear Palladium Complexes Pd2L2 and Pd2L2X2 (L=Me2PCH2PMe2; X=F, Cl, Br, I, H)

Qiu, Yixiang Li, Jia Wang, Shuguang   

  1. (School of Chemistry and Chemical Technology, Shanghai Jiaotong University, Shanghai 200240)
  • Received:2008-09-19 Revised:2009-02-26 Published:2009-07-28
  • Contact: Wang, Shuguang

采用ab initio HF, MP2方法和密度泛函理论方法, 对Pd(0), Pd(I)双核配合物Pd2L2和Pd2L2X2 (L=Me2PCH2PMe2; X=F, Cl, Br, I, H)的几何结构和电子结构进行了研究. 研究表明Pd2L2中Pd原子间的相互作用主要来自电子相关效应, Pd2L2X2中Pd原子间的相互作用则主要来自d轨道的成键作用. MP2方法和局域泛函Xα方法能对两类配合物的几何结构给予准确的描述. 在Pd2L2中, Pd原子的4d电子组成一一对应的成键、反键轨道, 轨道作用相互抵消使Pd原子间仅存在微弱的相互作用. X原子与Pd2L2的作用使Pd—Pd反键轨道电子占据数减少, 成键作用加强. 两类配合物的 Pd—Pd键长与NAO键级之间存在很好的线性关系. 还对Pd2L2和Pd2L2X2的低占据电子激发态进行了含时密度泛函理论计算, 分析不同配合物的电子跃迁特征, 并就卤素配体对Pd2L2X2光谱性质的影响进行了讨论.

关键词: 双核钯配合物, 密度泛函理论, Pd—Pd相互作用, 电子结构, 电子光谱

The molecular geometric and electronic structures of Pd(0) and Pd(I) dinuclear complexes Pd2L2 and Pd2L2X2 (L=Me2PCH2PMe2; X=F, Cl, Br, I, H) have been investigated by means of ab initio HF, MP2 and density functional theory (DFT) methods. It was found that the interaction between Pd atoms of Pd2L2 was mainly due to the electronic correlation, and the interaction between Pd atoms of Pd2L2X2 was mainly due to the bonding interaction of 4d orbitals. The MP2 and local spin density (LSD) Xα methods had good performance in reproducing the experimental geometric features. In Pd2L2, the counteractions of 4d bonding and anti-bonding orbitals largely weaken the strengths of Pd—Pd bond. However, the bonding of X atom with Pd2L2 makes the occupation of electrons in Pd—Pd anti-bonding orbitals reduced and bonding strength increased. There are good linear correlations between the Pd—Pd bond lengths and NAO Pd—Pd bond orders of Pd2L2 and Pd2L2X2 from the natural orbital analysis. The electronic absorption spectra of the Pd dinuclear complexes have been investigated by the TDDFT method. The influence of haloid ligands on the electronic spectra of Pd2L2X2 was also examined and some explanations were given by the changes of orbital energy level.

Key words: dinuclear palladium complex, density functional theory, Pd—Pd interaction, electronic structure, electronic spectra