物理化学学报 >> 2011, Vol. 27 >> Issue (09): 2035-2042.doi: 10.3866/PKU.WHXB20110903

理论与计算化学 上一篇    下一篇

2-(2-羟基苯亚甲基胺)-4,6-二羟基-嘧啶的质子转移异构化反应

周子彦1, 刘敏3, 苏忠民2, 谢玉忠3, 丁慎德1, 王华静1   

  1. 1. 山东理工大学化学工程学院, 山东淄博 255049;
    2. 东北师范大学化学学院功能材料化学研究所, 长春 130024;
    3. 延边大学理学院化学系, 吉林延吉 133002
  • 收稿日期:2011-02-28 修回日期:2011-05-26 发布日期:2011-08-26
  • 通讯作者: 周子彦 E-mail:zyzhou@sdut.edu.cn
  • 基金资助:

    国家自然科学基金(20703008)和山东省自然科学基金(ZR2009BL024)资助项目

Proton-Transfer Isomerization Reactions of 2-(2-Hydroxybenzylidenamino)pyrimidine-4,6-diol

ZHOU Zi-Yan1, LIU Min3, SU Zhong-Min2, XIE Yu-Zhong3, DING Shen-De1, WANG Hua-Jing1   

  1. 1. College of Chemical Engineering, Shandong University of Technology, Zibo 255049, Shandong Province, P. R. China;
    2. Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China;
    3. Department of Chemistry, College of Science, Yanbian University, Yanji 133002, Jilin Province, P. R. China
  • Received:2011-02-28 Revised:2011-05-26 Published:2011-08-26
  • Contact: ZHOU ZI-Yan E-mail:zyzhou@sdut.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20703008) and Natural Science Foundation of Shandong Province, China (ZR2009BL024).

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摘要： 为了探索2-(2-羟基苯亚甲基胺)-4,6-二羟基-嘧啶(M1)分子醇式和酮式结构互变异构化的反应机理, 利用密度泛函理论(DFT)方法, 在B3LYP/6-311+G(d, p)基组水平上, 对M1化合物异构化反应的势能面进行了研究, 在探讨各种可能的反应途径中, 发现单体至少有8 种异构体和10 种过渡态. 结果表明: 2-(2-羟基苯亚甲基胺)-6-羟基-4(3H)嘧啶酮(M6)不论是单体、与水形成的配合物, 还是二聚体, 比其相对应的异构体能量低, 表明在通常情况下是以M6形式稳定存在的; 在考察的可能反应途径中, 直接进行的分子内质子转移过程需要的活化自由能为143.8 kJ·mol-1, 水助催化时, 反应的活化自由能为38.9 kJ·mol-1, 二聚体双质子转移的活化自由能为0.6 kJ·mol-1, 二聚体双质子转移所需活化自由能最低, 在室温下就可以进行, 由此可见氢键在降低反应活化能方面起着重要的作用.

关键词: 2-(2-羟基苯亚甲基胺)-4,6-二羟基-嘧啶, 密度泛函理论, 互变异构, 质子转移

Abstract: To determine the tautomerism mechanism between the enol form and the keto form of 2- (2-hydroxybenzylidenamino)pyrimidine-4,6-diol (M1) the potential energy surface of the isomerization was studied using density functional theory (DFT) calculations at the B3LYP/6-311+G(d, p) level. We found that there were at least 8 isomers and 10 transition states in the possible reaction pathways. All the possible processes of the reaction were studied. The results showed that the energy of 6-hydroxy-2-(2- hydroxybenzylideneamino) pyrimidine-4(3H)-one (M6) was lower than those of the other isomers in the form of a monomer, a hydrate, and a dimer. Therefore, it was the most stable isomer. In these possible reaction pathways the activation free energy required for intramolecular prototropy was 143.8 kJ·mol-1 and for the proton transfer process that was catalyzed by water was 38.9 kJ·mol-1. The activation free energy in the double-proton transfer of the dimer was 0.6 kJ·mol-1, which was the lowest value. The latter pathway was feasible at room temperature. This implies that hydrogen bonding plays an important role in depressing the activation energy of the reaction.

Key words: 2-(2-Hydroxybenzylidenamino)pyrimidine)-4,6-diol, Density functional theory, Tautomerism, Proton transfer