1-锗蒽、2-锗蒽及9-锗菲二聚反应的理论研究

Theoretical study on dimerization reactions of 1-germaanthracene,2-germaanthracene and 9-germaphenanthrene

采用密度泛函B3LYP/6-311G**方法研究了1-锗蒽的[2+2]、[4+2]及[4+4]二聚反应、2-锗蒽及9-锗菲的[2+2]二聚反应的微观机理和势能剖面,考察了苯溶剂对反应势能剖面的影响,并与锗苯、1-锗萘及2-锗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-锗蒽的[4+2]反应最有利,而[4+4]反应最不利。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。苯溶剂对所研究反应的势能剖面影响较小。1-锗蒽(2-锗蒽)的反应性高于锗苯和1-锗萘(2-锗萘)。

Density functional theory（DFT）-B3LYP/6-311G＊ ＊ method was used to study the mechanism and potential energy sur- face of[ 2 ＋2 ], [ 4＋2 ] and [ 4＋4 ] dimerization reactions of 1-germaanthracene and [ 2 ＋2 ] dimerization reactions of 2-germaanthracene and 9-germaphenanthrene. The influence of benzene solvent on the potential energy surface of reactions was explored. The obtained results were compared with those of dimerization reactions of germabenzene, 1-germanaphthalene and 2-germanaphthalene studied previously. The results show that [ 2 ＋2 ] and [ 4 ＋4 ] reactions occur in a concerted and synchronous way, while [ 4 ＋ 2 ] reactions pro- ceed in a concerted but nonsynchronous way. [ 4＋2 ] Reactions of 1-germaanthracene are the most favorable beth thermodynamically and kinetically, while [ 4＋4 ] reactions are the most unfavorable. It seems that the difference between exo and endo approaches is not obvious beth in the thermodynamic and kinetic properties. Benzene, as a poor polar solvent, has only trivial influence on the potential energy surface of the studied reactions. 1-Germaanthracene （2-germaanthracene）has higher reactivity than germabenzene and 1-ger- manaphthalene （2-germanaphthalene）.