硅烯与异硫氰酸反应机理的量子化学研究  

Theoretical Study of Reaction Mechanism of Silylene with Isothiocyanic Acid

作　　者：韩彦霞[1,2,3] 耿志远[1,2] 王永成[1,2] 梁俊玺[1,2] 闫盆吉[1,2] 

机构地区：[1]西北师范大学化学化工学院,兰州730070 [2]甘肃省高分子重点实验室,兰州730070 [3]陇东学院化学化工学院,庆阳745000

出　　处：《化学学报》2009年第8期773-780,共8页Acta Chimica Sinica

基　　金：甘肃省自然科学基金(No.0710RJZ114);甘肃省教育厅导师基金(No.0801-10)资助项目

摘　　要：采用密度泛函理论B3LYP方法在B3LYP/6-311++G**水平上对反应物、中间体、过渡态进行了全几何参数优化,通过频率分析和IRC方法确认了中间体和过渡态.又用QCISD(T)/6-311++G**//B3LYP/6-311++G**方法计算了各个驻点的单点能,计算结果表明单重态的硅烯与异硫氰酸的反应有抽提硫、插入、抽提亚氨基的路径.而经由三元环中间体的抽提硫反应SiH2+HNCS→IM1→TS2→IM3→TS3→IM4→SiH2S+HNC(P1),反应能垒最低,为主反应通道,硫代硅甲醛和异氰氢酸为主产物.硅烯直接抽提硫、插入N-H键和经由三元环中间体的亚氨基抽提反应为竞争反应通道,在室温下可以发生,应为次反应通道.Using the DFT-B3LYP based on 6-311＋＋G^＊＊ basis set, the geometries of the reactants, the intermediates and the transition states were fully optimized at the B3LYP/6-311＋＋G^＊＊ level. The intermediates and the transition states were examined by using the frequency calculations and the intrinsic reaction coordinate （IRC）. Furthermore, single-point energy calculations were refined at the QCISD level of theory with the same basis set （6-311＋＋G^＊＊）. As a result, the singlet reaction of silylene with isothiocyanic acid contain S-atom abstraction channel, N--H inserted channel, and NH abstraction channel, respectively. The pathway written as SiH2 ＋ HNCS→IM 1→TS2→IM3→TS3→IM4→SiH2S ＋ HNC（P 1） was the main path- way, whose the activation energy was the lowest and the primary products were SiH2S and HNC, respectively. While the channel of NH abstraction, which was a minor channel comparing those of direct S-atom abstraction and N--H insertion, was the competitive reaction channel and can process under the room temperature.

关 键 词：硅烯 异硫氰酸 反应机理 活化能 过渡态 

分 类 号：O643.1[理学—物理化学]