氨基氰氢-迁移异构化反应的理论研究

Theoretical Study on The Hydrogen Transfer Isomerization of Cyanamide

利用Gaussian03程序,在B3LYP/6-311G**的水平下对氨基氰分子的腈式、亚胺式异构体构型,氨基氰.H2O复合物的腈式、亚胺式异构体构型,氨基氰.HF复合物的腈式、亚胺式异构体构型,氨基氰.NH3复合物的腈式、亚胺式异构体构型的稳定构型、以及氢-迁移异构化反应过程中可能过渡态(TS)的结构进行全参数优化.根据主要几何构型参数,比较其对应物的相对稳定性;结果表明各复合物腈式结构较亚胺式稳定,氨基氰分子分别与H2O、HF、NH3形成复合物后,进行氢-迁移引起的互变异构反应的活化能大大降低,使反应较易进行;在298.15 K和1.0×105Pa下,气相氨基氰与甲二亚胺分子间的异构反应,各催化剂小分子的催化效能顺序为:NH3>H2O>HF.

A detailed computational study is performed on the hydrogen - transfer isomerization of cyanamide. At the B3LYP/6- 311G＊＊ level, the configurations of isolated and complex cyanamide are optimized, and all their isomers and the structures of corresponding isomers and the possible hydrogen -transfer pathways, transition station. We discussed the relative stability of The result shows that： the energy difference between one pair of isomers is very little ; the neutral molecule can make the reaction easy and the order of their catalytic effectiveness is NH3 〉 H2O 〉 HF.