摘要
在UMP2 (FULL) / 6 311(d ,p)计算水平上 ,计算并讨论了碳氢自由基 (CHx)和异氰酸 (HNCO)发生氢转移反应位能面上驻点的结构和分子结构变化 ,并依据UMP2的优化构型 ,进一步采用UQCISD(T)方法对反应途径上的驻点进行了单点能量计算 .研究指出 ,HNCO同CH2 ,CH3 自由基反应时 ,氢转移过程在分子间以新的C—H键生成和旧的N—H键的断裂的协同方式进行 ,反应途径上均存在弱的氢键超分子复合物 ;而HNCO和CH分子之间发生的氢转移反应机理是在反应剖面的反应物一边生成一个较稳定的分子复合物HN(CH)CO ,而后 ,在生成物一边又生成一个既有热力学又有动力学稳定的复合物H2 CNCO .
The reaction path of isocyanic acid (HNCO) with carbon-hydrogen radicals CH, CH 2 and CH 3 have been investigated by using UMP2 method at 6-311g(d, p) level. The geometries of the stationary points and the changes of molecular structure along the reaction path are discussed. Furthermore, the UQCISD(T, full) single-point energy calculations were performed on the geometries optimized at UMP2/6-311G(d, p) level. For the reactions of HNCO with CH 2 and HNCO with CH 3, we found that the formation of new C-H bond concerted with the break of old N-H bond along the IRC, and that there was a weak hydrogen-bond hyper-molecular complex on the reactant side for the both reactions. However, for the reaction of HNCO with CH there were two stable molecular complexes HN(CH)CO and H 2CNCO on the reactant side and the product side, respectively
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第7期1167-1172,共6页
Acta Chimica Sinica
基金
国家教育部博士点基金 (No .9990 0 2 715 )
宁夏回族自治区教委基金资助项目
