化学学报 ›› 2000, Vol. 58 ›› Issue (11): 1476-1479. 上一篇    

研究论文

乙硼烷(B~2H~6)在醚溶液中分解的理论研究

范育波;王全瑞;丁宗彪;陶凤岗   

  1. 复旦大学化学系.上海(200433)
  • 出版日期:2000-11-15 发布日期:2000-11-15

A DFT study of dissociation of diborane (B~2H~6) in THF

Fan Yubo;Wang Quanrui;Ding Zongbiao;Tao Fenggang   

  1. Fudan Univ, Dept Chem.Shanghai(200433)
  • Online:2000-11-15 Published:2000-11-15

以二甲醚模拟四氢呋喃在乙硼烷分解过程中的作用。B3LYP/6-31G^*的计算结果发现,硼烷的分解是一个两步过程,每一步中均有一个醚分子与一个硼原子形成硼氧配位键,且只有一个氢桥键断裂。第一步反应的活化能为42.30kJ·mol^-^1,第二步的为4.33kJ·mol^-^1。当考虑溶剂效应时,第一步的活化能更降低为28.03kJ·mol^-^1。

关键词: 乙硼烷, 二甲醚, 分解, 密度泛函理论, 溶剂效应

The detailed dissociation mechanism of diborane (B~2H~6) in vacuum or in tetrahydrofuran (THF) media has been studied at B3LYP/6-31G^* level with dimethyl ether to simulate the involved THF. All the calculations indicate a two-step mechanism for the dissociation. Only one H-bridge bond is broken and one B-O bond is formed in the each S~N-2 like step. Comparing with the dissociation of B~2H~6 in vacuum or in hydrocarbon media, participation of Me~2O significantly lowers the activation barriers in the process. The barriers are further lowered when solvent effect is taken into account (28.03 kJ·mol^-^1 for the first step and 21.00kJ·mol^-^1 for the second one).

Key words: DIBORANE, DIMETHYL ETHER, DECOMPOSITION, SOLVENT EFFECT

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