甲基自由基与硅甲基自由基结构与电子性质的比较  

Comparison of Structures and Electronic Properties of Methyl Radical and Silyl Radical

作　　者：吕仁庆 吴冲冲 王芳 王淑涛 崔敏 LV Ren-Qing;WU Chong-Chong;WANG Fang;WANG Shu-Tao;CUI Ming(College of Science, China University of Petroleum(East China), Qingdao 266580, China;Department of Chemical and Petroleum Engineering, University of Calgary, T2N 1N4, Calgary, Alberta, Canada)

机构地区：[1]中国石油大学(华东)理学院,山东青岛266580 [2]卡尔加里大学化学与石油工程系

出　　处：《化学教育（中英文）》2019年第2期20-23,共4页Chinese Journal of Chemical Education

基　　金：中国石油大学(华东)教学实验技术改革项目(SY-B201615);山东省研究生优质课程建设项目(鲁学位[2017]1号);中国石油大学重点课程建设项目及中国石油大学教学研究与改革项目(JY-B201634;JY-A201819)

摘　　要：采用理论方法考察了甲基自由基和硅甲基自由基的结构和电子性质。结果表明,甲基自由基上的C和H分别带负电荷和正电荷,而硅甲基自由基上的Si和H分别带正电荷和负电荷。无论是甲基自由基还是硅甲基自由基,锥形结构的中心原子成键轨道的p轨道成分多于平面结构的p轨道成分;平面结构比锥形结构的中心原子更倾向于负电性化。甲基自由基的Laplacian电子密度值的符号为负,而硅甲基自由基的Laplacian电子密度值的符号为正。从而证实了Pauling关于电负性差异导致结构不同的论断。The MP2/6-311+G**theoretical method was employed to investigate the structures and electronic properties of methyl radical and silyl radical.The results show that C and H in methyl radical are negatively charged and positively charged,respectively,while Si and H in silyl radical are positively charged and negatively charged,respectively.The p orbital component of bonding orbital of central atom in puramidal structure is more than that of planar structure for both methyl radical and silyl radical.The central atom of planar structure tends to be electronegatire in comparison to that of pyramidal structure.The sign of Laplacian electron density for methyl radical is negative,while the sign of Laplacian electron density for silyl radical is positive. The conclusion that the difference between methyl and silyl radicals is due to different electronegativity proposed by Pauling was confirmed.

关 键 词：甲基自由基 硅甲基自由基 结构 电子性质 电负性 

分 类 号：O621.14[理学—有机化学]