Synthedses of Aklylsilanes and Study of the Ion-Molecule Reactions Related to their Properties

合成了烷基单硅烷、烷基二硅烷及其氘标记化合物，并测定了其EIMS。通过与它们的缩合相反应的比较，研究了它们的破碎机理。EIMS中出现的大部分碎片离子都可以用缩合相反应的类比来解释。单分子烷中m/ z73的主离子（CH_3SiH_2CH_2CH_2^+）通过s-p偶联得到稳定。从初始MO计算中，优化后的离子几何结构表明，SiH_2-CH_2键和相邻的CH_2-CH_2键比分子离子的键短，Si-C-C的键角接近直角。1,1,2,2 -四甲基二硅烷的特征离子也与单硅烷相同，为m/ z73。然而，从氘标记化合物的结果可以知道，这种离子（CH_3）_3Si^+的结构与单硅烷的结构有很大的不同。该分解反应的中间体被认为是四元环结构。采用LC/MS法测定了二甲基苯基氯硅烷（MW=170）的质谱。采用了两种洗脱液：CH_3CN和MeOH/AcONH_4。从样品和洗脱液之间离子分子反应的结果，可以研究样品分子的性质和反应性。根据两种洗脱液的差异，可以发现分子离子基m/z 170和m/z 171的强度比不同。

The alkylmonosilanes, alkyldisilanes and their deuterium labeled compounds were synthesized, and the EIMS were measured. The fragmentation mechanisms were studied in the comparison with their condensed phase reactions. Most of the fragment ions appeared in EIMS can be explained on the analogy of the condensed phase reactions. The main ion of m/z 73 (CH_3SiH_2CH_2CH_2^+) in monolanes is stabilized by s-p conjugation. From the abinitio MO calculation, the optimized geometry of this ion shows that the SiH_2-CH_2 bond and the neighboring CH_2-CH_2 bond become shorter than those of molecular ion and the bond angle of Si-C-C approaches to right angles. The characteristic ion of 1, 1, 2, 2-tetramethyldisilane is also m/z 73 as same as that of monosilanes. However, from the results of deuterium labeled compounds it can be known that the structure of this ion, (CH_3)_3Si^+, is quite different from that of monosilanes. The intermediate of this decomposition reaction is considered to be the four-membered ring structure. The mass spectra of dimethylphenylchlorosilane (MW=170) were measured by LC/MS method. Two kinds of the eluates, CH_3CN and MeOH/AcONH_4, were used. From the results of ion-molecule reaction between sample and eluate, it may become possible to investigate the properties and reactivities of the sample molecule. As the difference between both eluates it can be found that the intensity ratio between m/z 170 and m/z 171 of molecular ion group is different.