氮杂硅三环类化合物的质谱研究

本文对二十四个氮杂硅三环类化合物进行了质谱研究.测定了它们的低分辨质谱,收集了大部分化合物的高分辨质谱数据并进行了亚稳跃迁测定。结果表明,分子离子的稳定性、基峰的生成方式以及碎片离子的多少主要取决于取代基R的性质.分子的电子轰击质谱裂解存在三种基本方式:(1)断裂Si～R键,生成高度稳定的(M-R)~ 离子,碎片离子较少;(2)开环,失去碎片C_2H_3O;(3)开环,失去碎片CH_2O或CH_3O.用电荷自由基定域理论解释这类化合物的质谱裂解机理,并对影响分子离子稳定性的有关因素及影响基峰形成的原因进行了讨论.

Mass spectra of silatranes

Mass spectra of twenty four silatranes were studied in detail using high resolution mass spectrometry and metastable ion measurements. The stability of molecular ion, the mode of formation of the base peak and the number of tragment ions depend mainly upon the property of substituent group. The fragmentation of silatrane under electron impact can take the following three routes: (1) the cleavage of the Si-R bond to produce a highly stable ion (M-R)+; (2) the ring fragmentation with the lose of the fragment C2H3O; (3) openning of one of the ring followed by the loss of CH2O or CH3O. The fragmentation mechanisms were discussed in terms of charge radical localization.