锗苯与甲醛和二苯甲酮的Diels-Alder反应的计算研究  

Computational studies of the Diels-Alder reactions of germabenzenes with formaldehyde and benzophenone

作　　者：王岩[1] 周涛[1] 袁红霞[1] 

机构地区：[1]信阳师范学院化学化工学院,河南信阳464000

出　　处：《计算机与应用化学》2009年第11期1403-1406,共4页Computers and Applied Chemistry

摘　　要：采用密度泛函理论(DFT)在B3LYP/6-311G(d,p)水平对锗苯与甲醛和二苯甲酮的Diels-Alder反应的微观机理、势能剖面、取代基效应及溶剂化效应进行了理论计算。结果,所研究的反应均为协同的基元反应,形成Ge-O键的反应中,形成2个新键较大不同步,其它反应的不同步性相对较小。羰基碳原子上的苯基取代基于反应不利,而锗苯分子中锗原子上的C(CH_3)_3与CCl_3取代基则有利。在热力学和动力学上,有锗参与的反应均远比无锗的反应容易,而形成Ge-O键的反应比形成Ge-C键的反应容易,结果与实验一致。四氢呋喃溶剂对所研究反应的势能剖面影响较小。4个形成Ge-O键的反应在四氢呋喃溶剂中进行时,其活化能垒分别为38.03、89.75、29.92和29.87 kJ·mol^(-1)。The mechanism, potential energy surface, substituent effect and salvation effect of Diels-Alder reactions of germabenzenes with formaldehyde and benzophenone were investigated theoretically using density functional theory （DFT） at the B3LYP/6-311 G（ d, p） level. It was found that all the studied reactions proceed v/a a concerted way and the reaction forming one Ge-O bond has much larger asynchronicity in the bond-formation process than other reactions. Phenyl group at C atom of carbonyl disfavors the Dials-Alder reactions, while C（ CH3 ）3 and CCl3 groups have opposite effects. The reactions involving Ge atom proceed much more easily than other reactions both thermodynamically and kinetically. The reaction forming one Ge-O bond occurs more easily than that forming one Ge-C bond, which is in agreement with experimental observation. The influence of tetrahydrofuran （THF） solvent on the potential energy surface of the studied reactions is trivial. The activation barriers of four reactions forming one Ge-O bond in THF solvent are 38.03, 89. 75, 29.92 and 29. 87 kJ · mol^-1 respectively.

关 键 词：锗苯 甲醛 二苯甲酮 Diels—Alder反应 反应机理 密度泛函理论 

分 类 号：O641[理学—物理化学] TQ015.9[理学—化学]