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，测定了它们的EIMS。通过与凝聚相反应的比较，研究了它们的裂解机理。在EIMS中出现的碎片离子大多可以用凝聚相反应的类比来解释。单烷中m/z 73（CH_3SiH_2CH_2CH_2^+）的主离子是通过s-p共轭稳定的。从头计算结果表明，该离子的SiH_2-CH_2键和相邻的CH_2-CH_2键比分子离子的短，Si-C-C键角接近直角。1，1，2，2-四甲基二硅烷的特征离子m/z也为73，与单硅烷相同。然而，从氘标记化合物的结果可以知道，该离子（CH_3）_3Si^+的结构与甲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。用LC/MS法测定了二甲基苯基氯硅烷（MW=170）的质谱。采用乙腈和甲醇/乙酸乙酯两种洗脱液。从样品与水的离子-分子反应的结果，可以研究样品分子的性质和反应性。由于两种洗脱液之间的差异，可以发现分子离子组的m/z 170和m/z 171之间的强度比是不同的。

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.