甲硅烷基(硅烯)钌配合物中甲硅烷基甲氧基化反应机理的理论研究  

Reaction Mechanism for the Alkoxylation of a Silyl Ligand in the Silyl-(silylene)ruthenium Complex: A Density Functional Theory Study

作　　者：周莉[1] 李阳[1] 林芙蓉[1] 田迪英[1] 雷群芳[2] 方文军[2] 谢湖均[1] 

机构地区：[1]浙江工商大学应用化学系,杭州310018 [2]浙江大学化学系,杭州310028

出　　处：《有机化学》2015年第3期698-704,共7页Chinese Journal of Organic Chemistry

基　　金：国家自然科学基金(No.21203166);食品科学与工程浙江省重中之重一级学科开放基金(No.JYTsp2014111)资助项目~~

摘　　要：采用密度泛函理论(DFT),我们研究了甲硅烷基(硅烯)钌配合物Cp*Ru(CO)(=Si Mes2)Si Me3与甲醇发生反应的机理.整个反应机理包含以下四个步骤:(1)Ru=Si双键和甲醇发生1,2加成反应,随后通过消除Mes2Si(OMe)H生成Cp*Ru(CO)Si Me3;(2)甲硅烷基配体上的甲基以1,2-甲基的迁移方式从硅原子转移到Ru原子上,并与甲醇发生1,2加成反应,生成的甲烷脱离后产生Cp*Ru(CO)Si(OMe)Me2;(3)重复步骤(2)两次,得到甲氧基化的产物Cp*Ru(CO)Si(OMe)3;(4)异腈配位Ru原子后得到最终的产物Cp*Ru(CO)(CNt-Bu)Si(OMe)3.甲醇和Ru=Si双键的1,2加成是整个反应的决速步骤,自由能势垒为35.3 kcal/mol.此外,还研究了甲硅烷基(锗烯)钌配合物与甲醇的反应机理,相比硅烯配合物,锗烯配合物决速步的能垒相对较低,为31.8 kcal/mol.The mechanism for the reaction of a silyl（silylene） ruthenium complex Cp＊Ru（CO）（=Si Mes2）Si Me3 with methanol was investigated via the density functional theory（DFT） calculations. The mechanism includes four steps.（1） The reaction initiates via the 1,2-addition of methanol to the Ru = Si bond, followed by Mes2Si（OMe）H elimination to give Cp＊Ru（CO）Si Me3;（2） A methyl group of the silyl ligand migrates to Ru center via 1,2-Me migration, together with 1,2-addition of methanol, which is followed by the CH4 release to form Cp＊Ru（CO）Si（OMe）Me2;（3） Step（2） repeats twice to give the fully alkoxylated product Cp＊Ru（CO）Si（OMe）3.（4） Coordination of isonitrile affords final product Cp＊Ru（CO）（CNtBu）Si（OMe）3. The first step involving the 1,2-addition of methanol to the Ru=Si double bond is the rate-determining step for the whole reaction with a free energy barrier of 35.3 kcal/mol. The mechanism for the reaction of a silyl（germylene）ruthenium complex with methanol was also considered. The rate-determining step has relatively lower barrier of 31.8 kcal/mol in contrast to the silyl（silylene） ruthenium complex.

关 键 词：DFT计算 反应机理 锗烯配合物 硅烯配合物 

分 类 号：O641.4[理学—物理化学]