次黄嘌呤氢迁移反应机理的理论研究  

Theoretical Study on the Hydrogen Transfer Reaction Mechanism of Hypoxanthine

作　　者：张爱华[1] 杨宝华[1] 李琳[1] 施致雄 ZHANG Aihua;YANG Baohua;LI Lin;SHI Zhixiong(Yanjing Medical College,Capital Medical University,Shunyi 101300,China)

机构地区：[1]首都医科大学燕京医学院,北京顺义101300

出　　处：《信阳师范学院学报（自然科学版）》2022年第1期32-35,共4页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(21777107)。

摘　　要：采用密度泛函理论方法,在B3LYP/6-31G^(**)水平下研究了无水催化、水催化次黄嘌呤氢迁移反应的微观机理和势能曲线图。计算结果表明:(1)无水催化时次黄嘌呤经过四元环的过渡态,发生分子内氢迁移反应,实现烯醇式向酮式的转变;(2)1分子水催化次黄嘌呤氢迁移反应过渡态的结构为六元环;(3)2分子水催化次黄嘌呤氢迁移反应过渡态的结构为八元环,催化剂存在时发生的是分子间氢迁移反应。能量计算表明,水分子催化下次黄嘌呤氢迁移反应的活化能垒小于无水催化直接H迁移过程的活化能垒,另外,氢键在增大次黄嘌呤水合物稳定性、降低氢迁移反应活化能方面起到非常重要的作用。The hydrogen transfer reaction mechanism and potential energy surface of hypoxanthine(Hx)have been theoretically investigated using density functional theory(DFT)at the B3LYP/6-31G^(**) level,which included water as catalyst.The results showed that the H transfer reaction between enol form and keto form of Hx may take place via a cyclic transition state.(1)Without water as catalyst,the inner H transfer reaction may occur via 4-membered cyclic transition state.(2)With one water molecule as catalyst,the H transfer reaction of Hx involved 6-membered cyclic transition state.(3)With two water molecules as catalysts,the H transfer reaction of Hx belonged to an intermolecular H transfer reaction and its transition state is 8-membered cyclic structure.The study of the potential energy surface showed that H shift reaction may proceed more easily with two water molecules as catalysts.In addition,the effect of hydrogen bonds played an important role in increasing the stabilities of complexes on Hx with H 2O and lowering the activation energies of H shift.

关 键 词：次黄嘌呤 氢迁移反应 活化能 密度泛函理论 

分 类 号：O643.12[理学—物理化学]