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采用密度泛函理论(DFT)在B3LYP/6-31G(d)水平上,研究硅苯、1-硅萘及9-硅蒽的[4+4]二聚反应的微观机理和势能剖面,考察了反应的取代基效应和溶剂效应。计算结果表明,所研究反应均为协同反应,且2个C-Si键同步形成。随反应物分子芳香环从小到大的增加,[4+4]反应在热力学和动力学上均变得越来越有利。硅苯中硅原子上具有吸电子性质的CCl_3及具有给电子性质的NH_2取代基,在热力学和动力学上均有利于反应。苯溶剂对所研究反应的势能剖面影响较小。
The density functional theory (DFT) at the B3LYP / 6-31G (d) level was used to investigate the microscopic mechanism and potential energy profile of [4 + 4] dimerization of silanes, 1-silanaphthalene and 9-silanthrene The substituent effect and solvent effect of the reaction. The calculated results show that all the reactions studied are synergistic, and two C-Si bonds are formed simultaneously. With the small to large increase of the aromatic ring of reactant molecules, the [4 + 4] reaction becomes more and more thermodynamically and kinetically. CCl 3 with electron-withdrawing properties on the silicon atom in silicon benzene and the NH 2 substituent with electron donating properties are thermodynamically and kinematically favorable to the reaction. Benzene solvent has little effect on the potential energy profile of the studied reaction.