三环硅芳香化合物二聚反应的理论研究

Theoretical Study on the Dimerization Reactions of Some Tricyclic Silaaromatic Compounds

采用密度泛函理论方法在B3LYP/6-31G*水平研究了一些三环硅芳香化合物(1-硅蒽、2-硅蒽及9-硅菲)的可能的[2+2]、[4+2]及[4+4]二聚反应的微观机理和势能剖面,并与硅苯、1-硅萘及2-硅萘的类似反应进行了比较.计算结果表明,[2+2]和[4+4]反应为同步的协同过程,而[4+2]反应为非同步的协同过程.无论从热力学还是从动力学来看,1-硅蒽的[2+2]和[4+2]反应都远比[4+4]反应容易进行.两种不同的进攻方式(endo进攻与exo进攻)在热力学和动力学上的差别不大.1-硅蒽(2-硅蒽)的反应性高于硅苯和1-硅萘(2-硅萘),因此其稳定性低于硅苯和1-硅萘(2-硅萘).

The mechanism and potential energy surface of [2 ＋ 21, [4 ＋ 2] and [4 ＋ 4] dimerization reac- tions of some tricyclic silaaromatic compounds （1-silaanthracene, 2-silaanthracene and 9-silaphenanthrene） were stud- ied by using density functional theory （DFF） at the B3LYP/6-31G＊ level. The obtained results were compared with those of dimerization reactions of silabenzene, 1-silanaphthalene and 2-silanaphthalene studied previously. The results showed that [ 2 ＋ 2 ~ and [ 4 ＋ 4 ] reactions occur in a concerted and synchronous way, while [ 4 ＋ 2 ] reactions proceed in a concerted but nonsynchronous way. [ 2 ＋ 2 ] and [ 4 ＋ 2 ] Reactions of 1-silaanthracene proceed much more easily than corresponding ~4 ＋ 43 reactions both thermodynamically and kinetically. The difference between exo and endo approaches is not obvious both in the thermodynamic and kinetic properties. 1-Silaanthracene （2-silaanthra- cene） has higher reactivity and hence lower stability than silabenzene and 1-silanaphthalene （2-silanaphthalene）.