The Effect of Si d-Orbital in the Ion/Molecule Reactions of Organosilicon

本研究的目的是为有机硅阳离子和阴离子的易重排提供证据，并阐明在没有金属原子的有机化合物中没有观察到的特定反应的机制和影响因素。采用FTICR质谱法研究了硅烯阳离子自由基与烯烃分子的离子/分子反应。1-二甲基-1-硅环丁烷和1,1 -[D_6]二甲基-1-硅环丁烷通过70 ev电子电离生成了硅烯阳离子自由基[(CH_3)_2SiCH_2]^+和[(CD_3)_2SiCH_2]+。这些沉默烯阳离子自由基在FTICR细胞中分离后，在超高真空条件下（10 ^<-8>- 10 ^<-9> mbar）与乙烯、[_4]乙烯或丙烯分子反应。结果表明，在离子/分子反应中产生的加合离子应具有四元环结构。为了生成SiC多键，采用Bruker Apex^<TM+> 47e FT-ICR质谱仪和JEOL JMS SX/SX 1 02A四扇形串联质谱仪对2-adamantyl-4-叔丁基-2-三甲基硅氧基- 1,1-二（三甲基硅氧基）- 1-硅环丁烯进行了电子冲击电离（EI）、化学电离（CI）和快速离子轰击电离，以生成含有SiC双键或三键的离子。高分辨率质量测量结果表明，在m/ z330处，碎片离子的基本组成为C_<20>H_<34>Si_2^+。MS/MS/MS和从头算MO计算结果表明，m/ z330离子的结构为含Si=C双键的四元环。

The purpose of this study is to provide evidence for a facile rearrangement of organosilicon cations and anions and to clarify the mechanisms and the effective factors in the specific reactions which are not observed in organic compounds without metallic atoms.1. Ion/molecule reactions of silene cation radicals with alkene molecules were investigated using FTICR mass spectrometry. The silene cation radicals [(CH_3)_2SiCH_2]^+ and [(CD_3)_2SiCH_2]+ were generated by 70 eV-electron ionization of 1-dimethyl-1-silacyclobutane and l, 1-[D_6]dimethyl-1-silacyclobutane. After these silene cation radicals were isolated in the FTICR cell, they were allowed to react with ethene, [_4]ethene, or propene molecules under ultra-high-vacuum conditions (l0^<-8>-l0^<-9> mbar). The resulting FTICR spectra show that the adduct ions, produced in the ion/molecule reactions, should have a four-membered ring structure.2. In order to make an SiC multiple bond, an electron-impact ionization (EI), a chemical ionization (CI) and a fast-ion-bombardment ionization of 2-adamantyl-4-tert-butyl-2-trimethylsiloxy- 1,1-bis(trimethylsilyl)- l-silacyclobut-3-ene were examined in order to generate ions containing an SiC double or triple bond using both a Bruker Apex^<TM+> 47e FT-ICR mass spectrometer and a JEOL JMS SX/SX 1 02A four-sector tandem mass spectrometer. From the results of high-resolution mass measurement, the elementary composition of fragment ions at m/z 330 was found to be C_<20>H_<34>Si_2^+. The results of MS/MS/MS and ab initio MO calculations showed that the structure of the m/z 330 ion is a four-membered ring containing an Si=C double bond.