溶剂对环加成反应HN_3+NH_2CN→5-AT影响的理论研究(英文)

Theoretical Study on Solvent Effect on Cycloaddition Reaction: HN_3+NH_2CN→5-AT

采用B3LYP、QCISD、MP2方法在6-311+G*基组水平上对HN3+NH2CN→5-AT的环加成反应进行了研究,用气相条件下的计算方法结合SCRF/PCM模型对四氯化碳、丙酮、二甲亚砜、水四种不同溶剂下的反应性能进行计算,探讨了溶剂对反应的影响。结果表明,溶剂的极性对反应的影响不明显,从热力学角度考虑:反应在二甲亚砜溶剂中的平衡常数最大,说明反应在二甲亚砜溶剂中最容易自发进行;从动力学角度考虑:反应在各种溶剂中的速率常数均小于其在气相条件下的速率常数,说明反应在气相条件下更具有动力学优势。300～350 K是该反应的适宜温度。

Cycloaddition reaction HN3 ＋ NH2 CN → 5-AT has been theoretically investigated by B3LYP,QCISD and MP2 methods with 6-311 ＋G＊basis set. The solvent effects on the geometries,reaction path properties,energies,thermodynamic,and kinetic characters in four solvents（ carbon tetrachloride,dimethylsulfoxide,aceton,and water）have been studied by using self-consistent reaction field（SCRF）approach with the polarizable continuum model（ PCM）. Results show that effects of solvent on the geometric characters and reaction path properties are negligible. The equilibri-um constant in dimethylsulfoxide solvent is the largest,so the reaction easier occurred spontaneously in dimethylsulfoxide solvent thermodynamically. The rate constant in the solvents is smaller kinetically than that in gas phase,and 300 to 350 K is the most feasible temperature to the reaction.