物理化学学报 >> 2013, Vol. 29 >> Issue (05): 903-910.doi: 10.3866/PKU.WHXB201302272

热力学,动力学和结构化学 上一篇    下一篇

1-甲基胸腺嘧啶A-带结构动力学

李明娟, 刘明霞, 郑旭明   

  1. 浙江理工大学化学系, 先进纺织材料与加工技术教育部重点实验室, 生态染整技术教育部工程研究中心, 杭州 310018
  • 收稿日期:2012-12-18 修回日期:2013-02-27 发布日期:2013-04-24
  • 通讯作者: 郑旭明 E-mail:zxm@zstu.edu.cn
  • 基金资助:

    国家自然科学基金(21033002)和国家重点基础研究发展规划项目(973) (2013CB834604)资助

A-Band Structural Dynamics of 1-Methylthymine

LI Ming-Juan, LIU Ming-Xia, ZHENG Xu-Ming   

  1. Key Laboratory of Advanced Textiles Materials and Manufacturing Technology of the Ministry of Education, and Engineering Research Center for Eco-dyeing and Finishing of Textiles of the Ministry of Education, Department of Chemistry, Zhenjiang Sci-Tech University, Hangzhou 310018, P. R. China
  • Received:2012-12-18 Revised:2013-02-27 Published:2013-04-24
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21033002) and National Key Basic Research Program of China (973) (2013CB834604).

摘要:

获取了1-甲基胸腺嘧啶(MT)涵盖紫外光谱中A带和B带吸收的共5 个激发波长的共振拉曼光谱, 并结合密度泛函理论方法研究了MT的电子激发和Franck-Condon 区域结构动力学. 在TD-B3LYP/6-311++G(d,p)计算水平下, A带和B带吸收被分别指认为πHπL*/πH-2πL+2*πHπL+2/πH-2πL*跃迁. 甲基参与嘧啶环的共轭使MT的A带最大吸收波长λmax相对于胸腺嘧啶(T)发生明显红移, 并对Franck-Condon区域的动态结构产生一定影响. A带和B带共振拉曼光谱分别被指认为14 个振动模式和11 个振动模式的基频、泛频和组合频. C5=C6伸缩+C6H12面内弯曲振动v9, 环变形振动v16和N3C2N1反对称伸缩+C4C5C10反对称伸缩振动v18占据了A带共振拉曼光谱强度的绝大部分. 这表明1πHπL*激发态结构动力学主要沿这些反应坐标展开. 考察了溶剂对共振拉曼光谱的影响, 结果表明, C4=O9伸缩+N3H11面内弯曲振动v8的活性与溶剂性质有关, 其激发态位移量随溶剂性质的变化规律与胸腺嘧啶一致.

关键词: 1-甲基胸腺嘧啶, 结构动力学, 共振拉曼光谱, 密度泛函理论, 振动光谱, 电子光谱

Abstract:

Resonance Raman spectra at five excitations covering the A- and B-band absorptions of 1-methylthymine (MT) were acquired. The Franck-Condon region structural dynamics and electronic transitions of MT were studied in conjunction with density functional theory calculations. The A- and B-band absorptions are assigned as πHπL*/πH-2πL+2* and πHπL+2*/πH-2πL* transitions, respectively, using the B3LYP/6-311 + G(d,p) level of theory. The hyper-conjugation interaction between the CH3 group and pyrimidine ring leads to a noticeable red-shift in λmax of the A-band absorption for MT, relative to that for thymine. It also significantly affects the Franck-Condon region structural dynamics of MT. The A- and B-band resonance Raman spectra are respectively assigned as the 14 and 11 fundamentals, their overtones and combination bands.The A-band resonance Raman intensities of MT are dominated by the v9 (C5=C6 stretching + C6H12 in-plane bending), v16(ring deformation) and v18 (N3C2N1 asymmetric stretching+C4C5C10 asymmetric stretching) modes. This indicates that the structural dynamics of MT are mainly along these reaction coordinates. The effect of solvent on the structural dynamics was examined. The Raman activity of the v8(C4=O9 stretching+N3H11 in-plane bending) vibrational mode is tuned by solvent, and the dependence of the normal mode displacement of v8 on solvent is similar to that for thymine.

Key words: 1-Methylthymine, Structural dynamics, Resonance Raman spectrum, Density functional theory, Vibrational spectrum, Electronic spectrum

MSC2000: 

  • O641