【摘要】 使用量子化学中的Hartree-Fock方法和密度泛函理论中的B3LYP方法 ,分别在 3- 2 1G 和 6 - 31G(d)水平上 ,计算了尿酸分子从三羰基异构体向三羟基异构体的转化 .结果表明 ,转化过程经历了单羟基和双羟基异构体 2种中间物和 3种过渡态时的分子内质子转移 (IPT) ,转移中的H原子和邻近的N ,O和C原子形成了具有四元环结构的过渡态 .随着IPT的进行 ,N—H键逐渐被削弱和断裂 ,O—H键则逐渐生成 .3个反应的活化能分别为 190 3kJ/mol,181 4kJ/mol和 2 4 9 9kJ/mol(B3LYP/ 6 - 31G(d) ) .较高的活化能表明在室温下 ,无催化剂的IPT难以进行更多还原

【Abstract】 Quantum chemistry theory of Hartree-Fock method at the 3-21G * basis set level and density functional theory with B3LYP method at the 6-31 G( d ) basis set level were employed to study the intramolecular proton transfer(IPT)process of uric acid molecule.In order to convert the three-carbonyl-group tautomer into the three-hydroxy-group one,the reaction undergoes two intermediates and three transition states.A four-membered cyclic substructure was formed in the transition state which involving transferring hydrogen atom and its neighboured nitrogen,oxygen and carbon atoms.The activation energies of the three reactions including scaled zero-point vibrational energies predicted by B3LYP/6-31G( d )are 190.3 kJ/mol,181 4 kJ/mol and 249 9 kJ/mol respectively and the last reaction is rate-determining step.更多还原