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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (11): 1012-1018. 上一篇    下一篇

研究论文

5-甲基胞嘧啶-BH3复合物构型及异构化机理的理论研究

靳玲侠1, 王文亮*,1, 吴东兵2, 王渭娜1   

  1. (1陕西师范大学化学与材料科学学院 陕西省大分子科学重点实验室 西安 710062)
    (2延安大学化学化工学院 延安 716000)
  • 投稿日期:2006-09-11 修回日期:2006-11-15 发布日期:2007-06-14
  • 通讯作者: 王文亮

Theoretical Study on the Structures and Isomerization Mechanisms of 5-Methylcytosine-BH3 Complexes

JIN Ling-Xia1; WANG Wen-Liang*,1; WU Dong-Bing2; WANG Wei-Na1   

  1. (1 Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Mate-rials Science, Shaanxi Normal University, Xi'an 710062)
    (2 Department of Chemistry and Chemical Engineering, Yan'an University, Yan'an 716000)
  • Received:2006-09-11 Revised:2006-11-15 Published:2007-06-14
  • Contact: WANG Wen-Liang

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用B3LYP/6-311＋G(d)及MP2/6-311＋G(d)计算方法, 对5-甲基胞嘧啶与BH3所形成复合物及异构化反应进行了研究, 获得了6种复合物及4个异构化过渡态. 在考虑基组重叠误差校正基础上, 得到了结合能及变形能等信息, 并用自然键轨道分析法讨论了其相互作用情况. 结果表明, BH3与5-甲基胞嘧啶中N(3), O及N(4)相连形成稳定复合物a, b1, b2和c, 其结合能分别为104.58, 92.25, 63.49和43.41 kJ•mol－1; 复合物a, b1, b2, c和d既可通过BH3与5-甲基胞嘧啶不同部位结合直接生成, 也可通过BH3整体迁移实现相互转化; 甲基化对复合物稳定性及相互异构化能垒无明显影响.

关键词: B3LYP, MP2, 5-甲基胞嘧啶, BH3, 复合物, 异构化反应

The structures and isomerization reactions of 5-methylcytosine-BH3 complexes have been investigated by the B3LYP and MP2 methods with 6-311＋G(d) basis set. 6 complexes and 4 transition states were located. Natural bond orbital analysis was performed to reveal the origin of intermolecular interaction. To obtain the accurate binding energies and potential energy surface, single point energy calculations and BSSE correction were performed. The results indicate that a, b1, b2 and c with BH3 directly combining N(3), O or N(4) are stable complexes with the binding energies of 104.58, 92.25, 63.49 and 43.41 kJ•mol－1, respectively. The complexes may be formed with BH3 directly combining to 5-methylcytosine as well as with BH3 entirely transferring on 5-methylcytosine-BH3. The influence of cytosine methylation was not obvious on stabilization orders and the energy barriers of isomerization.

Key words: B3LYP, MP2, 5-methylcytosine, BH3, complex, isomerization