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用量子化学从头算和密度泛函理论(DFT)对CH3S与CH2SH自由基反应进行了研究。在B3LYP/6-311+G(d,p)水平上优化了反应通道各驻点物种(反应物、中间体、过渡态和产物)的几何构型,用内禀反应坐标(IRC)计算和频率分析的方法对过渡态结构及连接性进行了验证。在QCISD(T)/6-311++G(d,p)水平上计算了各物种的单点能,并对总能量进行了零点能校正。研究结果表明,CH3S与CH2SH反应为多通道反应,有3条可能的反应通道。反应物首先通过C-S键相互作用形成链状碳-硫偶合中间体IM1,再经过裂解和脱氢气机理生成主要产物P1(CH3SH+CH2S)和次要产物P2和P3。根据势能面分析,所有反应均为吸热反应。相对于CH3S与CH2SH,各产物能量分别为(-175.2,335.5和331.5)kJ.mol-1。
The free radicals of CH3S and CH2SH have been studied by ab initio and density functional theory (DFT). The geometry of each stationary species (reactant, intermediate, transition state and product) of the reaction channel is optimized at the B3LYP / 6-311 + G (d, p) level using the intrinsic reaction coordinate (IRC) Frequency analysis of the transition state structure and connectivity were verified. The single point energy of each species was calculated at QCISD (T) / 6-311 ++ G (d, p) level and the total energy was corrected for zero point. The results showed that CH3S reacted with CH2SH to multi-channel reaction, with three possible reaction channels. The reactants firstly interact with each other through the C-S bond to form the chain carbon-sulfur coupling intermediate IM1. The main products P1 (CH3SH + CH2S) and the minor products P2 and P3 are formed by the pyrolysis and dehydrogenation mechanism. According to the potential energy surface analysis, all reactions are endothermic. Relative to CH3S and CH2SH, the energy of each product was (-175.2, 335.5 and 331.5) kJ.mol-1.