Department of Physical and Organic Chemistry, Institute Jozef Stefan, Jamova c. 39, SI-1000 Ljubljana, Slovenia.
J Phys Chem A. 2010 Jan 21;114(2):1147-52. doi: 10.1021/jp909603z.
The singlet potential energy surface for the CF3S + NO2 reaction has been theoretically investigated using the B3LYP/6-311+G(3df) level of theory. The geometries, vibrational frequencies, and zero-point energies of all stationary points involved in the title reaction have been examined. More accurate energies of stationary points were obtained using ab initio G3//B3LYP and CBS-QB3 composite methods. The results show that the initial addition of CF3S with NO2 leads to CF3SNO2 or CF3SONO intermediates, which are formed without an electronic barrier. CF3SNO2 can easily isomerizes to CF3SONO, while CF3SONO readily isomerizes to CF3S(O)NO or dissociates to CF3SO + NO, which are the major products of the title reaction. Reaction channels leading to the formation the CF3O + SNO and CF2S + FNO2 products are highly improbable processes due to high energy barriers involved. We have also computed heats of formation for CF3SNO2, CF3SONO, and CF3S(O)NO intermediates. It was found that the most stable is the cis-perpendicular form of CF3SONO isomer with DeltaH(f,0)0 = -243.6 kcal mol-1.
采用 B3LYP/6-311+G(3df)理论水平对 CF3S+NO2 反应的单重势能面进行了理论研究。研究了标题反应中所有涉及的驻点的几何形状、振动频率和零点能。使用从头算 G3//B3LYP 和 CBS-QB3 组合方法获得了更准确的驻点能量。结果表明，CF3S 与 NO2 的初始加成导致 CF3SNO2 或 CF3SONO 中间体的形成，而无需电子势垒。CF3SNO2 可以很容易地异构化为 CF3SONO，而 CF3SONO 很容易异构化为 CF3S(O)NO 或解离为 CF3SO + NO，这是标题反应的主要产物。由于涉及到高能量势垒，导致形成 CF3O + SNO 和 CF2S + FNO2 产物的反应通道是极不可能的过程。我们还计算了 CF3SNO2、CF3SONO 和 CF3S(O)NO 中间体的生成热。结果发现，最稳定的异构体是 CF3SONO 的顺式-垂直形式，其 DeltaH(f,0)0 = -243.6 kcal mol-1。
