物理化学学报 >> 2010, Vol. 26 >> Issue (05): 1429-1434.doi: 10.3866/PKU.WHXB20100325

量子化学及计算化学 上一篇    下一篇

杂环型稳定硅烯插入HF、H2O和NH3反应

孙龙, 解菊   

  1. 扬州大学化学化工学院, 江苏 扬州 225002
  • 收稿日期:2009-10-15 修回日期:2010-01-08 发布日期:2010-04-29
  • 通讯作者: 解菊 E-mail:xieju@yzu.edu.cn

Insertion Reactions of Heterocyclic Stable Silylenes into HF, H2O and NH3

SUN Long, XIE Ju   

  1. College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu Province, P. R. China
  • Received:2009-10-15 Revised:2010-01-08 Published:2010-04-29
  • Contact: XIE Ju E-mail:xieju@yzu.edu.cn

摘要:

硅烯为卡宾的硅类似物, 在有机光和热化学中作为一类重要的反应活性中间体引起了化学界的广泛兴趣. 杂环型硅烯是实验合成的稳定硅烯, 因其在有机硅化学中的重要作用, 十几年来在实验和理论上均有研究报道. 本文基于单重态杂环型硅烯的特殊电子性质和丰富的化学反应性, 系统探讨了几种杂环型硅烯的插入反应. 使用密度泛函理论(DFT), 在B3LYP/6-311++G(d,p)水平上研究了三种氮杂环型不饱和硅烯(1, 3, 4)和两种氮杂环型饱和硅烯(2, 5)分别与H—X (X=F, OH, NH2)键的插入反应, 阐明了插入反应的机理并对各反应的结果进行了比较. 杂环型硅烯与H—X的插入反应机理类似于简单硅烯, 体现了硅烯的亲电亲核的双重反应性. 由反应势垒和反应热看, 五种硅烯与H—X键的插入反应均为HF最容易, H2O次之, NH3最难. 饱和硅烯的反应性比不饱和硅烯的反应活性高, 这也间接验证了杂环型饱和硅烯在实验中较难合成.

关键词: 杂环型稳定硅烯, 插入反应, 过渡态, 能垒

Abstract:

Divalent silicon species (silylenes) corresponding to carbenes in organic chemistry are key intermediates in numerous thermal and photochemical reactions of organosilicon compounds. Considering the electronic characteristics of this class of compounds, the higher homologues of the nitro-heterocyclic silylenes are also of interest and have been studied experimentally and theoretically. This prompted us to take a closer look at the chemical behavior of nitro-heterocyclic silylenes on a theoretical basis. The insertion reactions of nitro-heterocyclic unsaturated stable silylenes (1, 3, 4) and nitro-heterocyclic saturated silylenes (2, 5) into HF, H2O, and NH3molecules were performed using density functional theory (DFT) at the B3LYP/6-311++G(d,p) level. The insertion mechanisms were investigated and results from various reactions were compared. The results indicated that the insertion reaction mechanisms of heterocyclic silylenes and HX were similar to those of simple silylene. From the reaction energy barrier and the reaction enthalpy, the insertion reaction could occur easily according to the following order: HF>H2O>NH3. The reaction activities of saturated silylenes were stronger than those of unsaturated silylenes. Therefore, it is difficult to synthesize heterocyclic saturated silylenes.

Key words: Heterocyclic stable silylene, Insertion reaction, Transition state, Energy barrier

MSC2000: 

  • O641