1,1-Dimethylsilirane | 70262-75-8

• 分子结构分类: 有机化合物 - 有机杂环化合物
• 英文名称: 1,1-Dimethylsilirane
• CAS: 70262-75-8
• 化学式: C₄H₁₀Si
• 分子量: 86.2089
• InChiKey: FCEOAGVSDADLCM-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.71
• 重原子数：
  5
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  1.0
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为产物：
  描述：

  乙烯 、 二甲基-二(三甲基硅烷基)硅烷 在 六氟化硫 作用下， 293.0 ℃ 、331.97 Pa 条件下， 生成 1,1-Dimethylsilirane
  参考文献：
  名称：

  Direct Gas-Phase Kinetic Studies of Silylene Addition Reactions:  SiH₂ + C₃H₆, SiH₂ + i-C₄H₈, and SiMe₂ + C₂H₄. The Effects of Methyl Substitution on Strain Energies in Siliranes

  摘要：

  Time-resolved studies of the title reactions have been carried out over the pressure range 1-100 Torr (in SF6 bath gas) and at temperatures in the range 293-600 K, using laser flash photolysis techniques to generate and monitor the silylenes, SiH2 and SiMe2. All three reactions showed evidence of pressure dependence, consistent with third-body assisted association reactions to form silirane products. Extrapolation of the pressure-dependent rate constants gave the following Arrhenius parameters: SiH2 + C3H6, log(A/cm(3) molecule(-1) s(-1)) = -9.79 +/- 0.03, E-a (kJ mol(-1)) = -1.9 +/-: 0.3; SiH2 + C4H8, log(A/cm(3) molecule(-1) s(-1)) = -9.91 +/- 0.04, E-a (kJ mol(-1)) = -2.5 +/- 0.3; SiMe2 + C4H8, log(A/cm(3) molecule(-1) s(-1)) = -12.12 +/- 0.02, E-a (kJ mol(-1)) -8.5 +/- 0.2. These parameters are consistent with fast, nearly collision-controlled processes for SiH2 but a tighter transition state for SiMe2. Rice, Ramsperger, Kassel, Marcus theory (RRKM) modeling, based on consistent transition states for silirane decomposition, and employing a weak collisional deactivation model, gave good fits to the pressure-dependent curves for each system, provided an appropriate value of E-a (fitting parameter) was used for each reaction. The kinetic results are consistent with an electrophilically led addition mechanism, although methyl substitution in the alkene hardly affects the rate constants. The RRKM-derived E-o values have been used to derive reaction enthalpies which are in reasonable agreement with values obtained by ab initio calculations at the G2 (MP2,SVP)level. The experimental Delta H degrees values yield strain energies of 190, 196, and 216 kJ mol(-1) for 2-methyl-, 2,2-dimethyl-, and I,1-dimethylsilirane, respectively. Compared to the strain enthalpy of 167 kJ mol(-1) for silirane itself, this shows that methyl substituents in the silirane products substantially increase the strain energies. Theory supports this.

  DOI：

  10.1021/jp981957f

文献信息

• Direct Gas-Phase Kinetic Studies of Silylene Addition Reactions:  SiH₂ + C₃H₆, SiH₂ + <i>i</i>-C₄H₈, and SiMe₂ + C₂H₄. The Effects of Methyl Substitution on Strain Energies in Siliranes
  作者：N. Al-Rubaiey、I. W. Carpenter、R. Walsh、R. Becerra、M. S. Gordon

  DOI：10.1021/jp981957f

  日期：1998.10.1

  Time-resolved studies of the title reactions have been carried out over the pressure range 1-100 Torr (in SF6 bath gas) and at temperatures in the range 293-600 K, using laser flash photolysis techniques to generate and monitor the silylenes, SiH2 and SiMe2. All three reactions showed evidence of pressure dependence, consistent with third-body assisted association reactions to form silirane products. Extrapolation of the pressure-dependent rate constants gave the following Arrhenius parameters: SiH2 + C3H6, log(A/cm(3) molecule(-1) s(-1)) = -9.79 +/- 0.03, E-a (kJ mol(-1)) = -1.9 +/-: 0.3; SiH2 + C4H8, log(A/cm(3) molecule(-1) s(-1)) = -9.91 +/- 0.04, E-a (kJ mol(-1)) = -2.5 +/- 0.3; SiMe2 + C4H8, log(A/cm(3) molecule(-1) s(-1)) = -12.12 +/- 0.02, E-a (kJ mol(-1)) -8.5 +/- 0.2. These parameters are consistent with fast, nearly collision-controlled processes for SiH2 but a tighter transition state for SiMe2. Rice, Ramsperger, Kassel, Marcus theory (RRKM) modeling, based on consistent transition states for silirane decomposition, and employing a weak collisional deactivation model, gave good fits to the pressure-dependent curves for each system, provided an appropriate value of E-a (fitting parameter) was used for each reaction. The kinetic results are consistent with an electrophilically led addition mechanism, although methyl substitution in the alkene hardly affects the rate constants. The RRKM-derived E-o values have been used to derive reaction enthalpies which are in reasonable agreement with values obtained by ab initio calculations at the G2 (MP2,SVP)level. The experimental Delta H degrees values yield strain energies of 190, 196, and 216 kJ mol(-1) for 2-methyl-, 2,2-dimethyl-, and I,1-dimethylsilirane, respectively. Compared to the strain enthalpy of 167 kJ mol(-1) for silirane itself, this shows that methyl substituents in the silirane products substantially increase the strain energies. Theory supports this.