The study of detection for transient silicon compuneds using a Fourier transform microwave spectrometer

为了研究在有机硅反应中起重要作用的二甲基硅烷，我们尝试在二甲基氯硅烷和三甲基二甲基硅烷的热解和排放反应中检测二甲基硅烷。傅里叶变换微波谱仪没有观察到它，但是，观察到母物质的许多旋转转变。因此，对DMC1Si和TMDMSi的分子结构和振动运动进行了研究。此外，在硅烷放电反应中，还检测到短寿命分子Si2H2的10.1 -000跃迁。用傅里叶变换微波光谱仪研究了氯二甲基硅烷的5 ~ 20 GHz微波光谱。用取代法得到的（CH_3）_2SiHCl的分子结构为：r_s(Si-Cl) = 2.0604 (10) A^^°，r_s(Si-C) = 1.8542 (10) A^^°，/ClSiC = 108.43（20）°，/CSiC = 112.32（15）°。得到氯原子的四极耦合常数，得到氯原子的离子特征为x_<zz> = -35.556 (6) MHz, 65%。两个甲基顶内旋势势垒V_3的估价值与相关分子的估价值一致。对1,1 -二甲基硅环丁烷的正常、^<29>Si、^<30>Si和^<13>C三种同位素进行了a型跃迁。除了甲基上的^<13>C种外，由于两个甲基顶的内部旋转和环起皱引起的分裂，每个过渡都有六个组分。甲基上的2个^<13>C的光谱与环上的2个^<13>C的光谱有很大的不同。两个甲基顶内旋势势垒V_3的估价值与相关分子的估价值一致。

In order to investigate shote lived dimethylsilane which plays important role in organosilicon reactions, we tried to detect dimethylsilane in the pyrolysis and discharge reactions of dimethylchlorosilane and trimethylenedimethylsilane. It has not been observed by means of a Fourier transform microwave spectrometer, however, many rotational transitions of the parent species were observed. Therefore the molecular structures and vibrational motions of DMC1Si and TMDMSi were studied. In the addition, the 101-000 transition of a short lived molecule, Si2H2, was detected during a discharge reaction of silane.The microwave spectra of five isotopic species of chlorodimethylsilane have been investigated in the region 5 to 20 GHz using a Fourier transform microwave spectrometer. The molecular structure of (CH_3)_2SiHCl obtained by the substitution method is the following one: r_s(Si-Cl) = 2.0604 (10) A^^°, r_s (Si-C) = 1.8542 (10) A^^°, /ClSiC = 108.43 (20)°, and /CSiC = 112.32 (15)°. The quadrupole coupling constants of the chlorine atom was obtained and yielded x_<zz> = -35.556 (6) MHz and 65 % as an ionic character of the chlorine atom. The estimated value of the potential barrier V_3 of internal rotation of two methyl tops is in agreement with those of the related molecules.The a-type transitions of isotopic species, normal, ^<29>Si, ^<30>Si, and ^<13>C, of 1, 1-dimethylsilacyclobutane were observed and assigned. Each transition except ^<13>C species in the methyl group has six components because of the splittings due to the internal rotation of two methyl tops and the ring puckering. The observed spectra of two ^<13>C species in the methyl group were much complicated and distinguished from the spectra of two ^<13>C species in the ring. The estimated value of the potential barrier V_3 of internal rotation of two methyl tops is in agreement with those of the related molecules.