氮磷杂环丙烯络合物合成1,2-氮磷杂茂络合物反应机理的理论研究

用密度泛函方法在B3LYP/6-31G*(除W原子采用LanL2DZ基组以外)水平上研究了氮磷杂环丙烯络合物(2H- azaphosphirene complex)热解生成1,3-偶极体腈磷叶立德络合物(nitrilium phosphanylide complex)以及腈磷叶立德络合物(nitrilium phosphanylide complex)与炔(alkyne)反应生成1,2-氮磷杂茂络合物. 结果表明, 第一步反应, 即开环反应生成亚磷烯络合物, 为反应的决速步骤, 其位垒为84.3 kJ•mol^－1, 然后生成的亚磷烯络合物与氰发生终端1,1]加成反应生成腈磷叶立德络合物, 最后该腈磷叶立德络合物与炔发生3＋2]加成反应, 越过很低的位垒即可生成热力学稳定产物1,2-氮磷杂茂络合物. 此外, 还研究了不同取代基和催化剂五羰基合钨对反应机理及反应位垒的影响.

Theoretical Study on the Potential Energy Surface of the Reaction from 2H-Azaphosphirene Complex to 2H-1,2-Azaphosphole Complex

Density functional theory B3LYP/6-31G* (except W with LanL2DZ basis set) has been employed to explore the mechanism of thermolysis of 2H-azaphosphirene complex to nitrilium phosphanylide complex, which could react with alkyne to yield 2H-1,2-azaphosphole complex. The obtained results indicate that the ring-opening reaction of 2H-azaphosphirene complex to phosphinidene is the rate-controlling one, which needs to overcome 84.3 kJ•mol^－1 energy barrier, and then the produced phosphinidene complex could react with cyanogens to yield nitrilium phosphanylide complex, which could further react with alkyne to generate the thermodynamically stable product 2H-1,2-azaphosphole complex. In addition, the catalytic effect of W(CO)₅ and substitution effect on the reaction mechanisms and reaction barriers have also been considered.