TADFIW水解反应机理的密度泛函理论

摘要

应用密度泛函理论(DFT)在B3LYP/6-31G(d,p)水平下对四乙酰基二甲酰基六氮杂异伍兹烷(TADFIW)甲酰基的水解反应机理进行了研究.结果表明,TADFIW上的甲酰基水解时,甲酰基被质子化,碳氧双键中的氧原子带有负电荷0.619 e,碳原子带有正电荷0.471 e,亲核试剂水分子进攻质子化甲酰基的碳原子,同时,碳氮键键长由0.1310 nm增至0.1491nm.水分子中的一个氢原子与氧原子断裂,向氮原子转移.该反应的活化能为125.92 kJ/mol,从热力学上看,TADFIW中甲酰基的水解反应比较容易发生.按照同样的方法设计了TADFIW上乙酰基的水解反应过渡态,乙酰基水解反应活化能为158.76 kJ/mol.TADFIW中的甲酰基较乙酰基优先发生水解反应.%The hydrolysis mechanism of formoxyl of TADFIW was studied by a density-functional theory method in B3LYP/6-31G(d,p) level. The results showed that, when hydrolysis reaction of formoxyl of TADFIW took place, the oxygen atom of carbon-oxygen double bond had negative charges with 0. 619e,while the carbon atom had positive charges with 0. 471e in transition state. The carbon atom of formoxyl was attacked by the nucleophilic reagent water molecule. The bond length of carbon-nitrogen increased from 0. 1310 mm to 0. 1491 mm. One hydrogen atom of water molecule was separated from the oxygen atom and transferred to the nitrogen atom. The activation energy was 125. 92 kJ/mol. The hydrolysis of the formoxyl of TADFIW easily took place from the view of thermodynamics. The transition state of the hydrolysis reaction of one acetyl was designed. The activation energy was 158. 76 kj/mol. The formoxyl had a prior reaction over acetyl in TADFIW.