物理化学学报 >> 2000, Vol. 16 >> Issue (04): 317-324.doi: 10.3866/PKU.WHXB20000406

研究论文 上一篇    下一篇

金属原子(离子)-苯配合物的电子转移反应

傅爱萍, 杜冬梅, 周正宇, 俞庆森   

  1. 曲阜师范大学化学系,曲阜 2713165|浙江大学化学院,杭州 310027|山东大学晶体材料国家重点实验室,济南 250100
  • 收稿日期:1999-07-19 修回日期:1999-09-27 发布日期:2000-04-15
  • 通讯作者: 周正宇

Electron Transfer Reaction Mechanism between M-C6H6 and M+-C6H6 Complexes

Fu Ai-Ping, Du Dong-Mei, Zhou Zheng-Yu, Yu Qing-Sen   

  1. Department of Chemistry,Qufu Normal University,Shandong Qufu 273165|School of Chemistry,Zhejiang University,Zhejiang Hangzhou 310027|State Key Lboratory,Crystal Materils Shandong University,Shandong Jinan 250100
  • Received:1999-07-19 Revised:1999-09-27 Published:2000-04-15
  • Contact: Zhou Zheng-Yu

摘要:

用密度泛函理论 (DFT/BLYP)在6-31G基组水平上研究了金属原子-苯与离子-苯配合物的气相电子转移过程 ,得到了M(Li, Na ,Mg)-C6H6 和M+-C6H6 络合物以及它们之间电子转移过程中的先驱络合物的最优几何构型和电子结构. 同时 ,利用线性坐标确定了过渡态的结构. 结果表明 :DFT方法计算得到的单体 ,即原子 (离子)-苯的构型 ,同MP2结果较为一致. 先驱络合物具有C6v对称性 ,给体与受体间距离在0.30~0.36nm ,络合物的稳定化能在0.9~1.5eV之间 ,表明两者间存在较强的相互作用. 另外 ,通过分析过渡态及单体的原子上的电荷分布 ,对电子转移的反应机理进行了探讨 ,给出了反应活化能及电子转移反应的耦合矩阵元 ,并进一步计算出反应的速率常数.对于电子转移反应的重组能 ,通过George Griffith Marcus(GGM)公式(只包含力常数矩阵中的对角元素的贡献)和Hessian矩阵法(包括对角元素和非对角元素的贡献)进行了计算. 结果表明,不同振动模式间的耦合作用对气相电子转移反应的内氛重组能有重要影响.

关键词: 密度泛函理论, 电子转移反应, 先驱络合物, 过渡态

Abstract:

 DFT/BLYP method is used to investigate theoretically the electron transfer (ET) reactions between M(Li, Na, Mg)-C6H6 and M+-C6H6 complexes in the gas phase. The geometry optimization of the metal-benzene complexes and the encounter state in the process of ET reaction was performed at 6-31G basis set level. The precursor complex has C6 symmetry, the distance between acceptor and donor is about 0.30~0.36 nm, which yields the bonding energy approximately 0.9~1.5 eV. It shows that there are relatively strong interactions between them. The geometry of transition state is also obtained by the linear coordinate method. The activation energy, the coupling matrix element and the rate constant of the ET reaction are calculated. According to the reorganization energy of the ET reaction, the values obtained from George-Griffith-Marcus (GGM) method (the contribution only comes from the diagonal elements of the force constant matrix) are larger than those obtained from Hessian matrix method (including the contribution from both diagonal and off -diagonal elements),which suggests that the coupling interactions between different vibrational modes are important to the inner-sphere reorganization energy for the ET reactions in gaseous phase.

Key words: Density functional theory, Electron transfer rection, Encounter complex, Transition state