一些重酮体系与水的亲核加成反应的计算研究

Computational Study of the Nucleophilic Addition Reactions between some Heavy Ketones and Water

采用密度泛函理论(DFT)方法在B3LYP/6-311++G(d,p)水平上对4类重酮体系的模型化合物(H2X=Y,X为Si或Ge,Y为S或Se)与水的亲核加成反应的反应机理和势能剖面进行了理论计算研究,利用Bader的AIM(Atomin Molecules)理论对反应过程进行了电子密度拓扑分析研究.结果表明,所研究的4个反应的反应机理完全相同,即:两反应物分子首先经过一无能垒过程形成中间体络合物,该中间体络合物再经过4元环过渡态形成产物.4个反应的活化能垒分别为17.87、18.32、35.32及40.25 kJ/mol.所研究的4个双键体系的反应活性顺序为:Si S>Si Se>Ge S>Ge Se.

DFT calculations at the B3LYP/6-311 ＋＋G（ d, p） level were employed to study the mechanism and the potential energy surface of the nucleophihc addition reactions between model compounds of four heavy ketones and water. The electron density topological analysis was carried out for the reaction process according to Bader＇ s AIM theory. The results show that all of four reactions proceed in the same way： 1 ） two reactant molecules form an intermediate complex with no energy barrier; 2） the intermediate complex isomerizes to give the product via a four-member ring transition state, the energy barriers are 17.87, 18.32, 35.32 and 40.25 kJ/mol, respectively. The reactivity order of four double bonds is ： Si=S〉Si=Se〉Ge=S〉Ge=Se..