物理化学学报 >> 2011, Vol. 27 >> Issue (01): 32-38.doi: 10.3866/PKU.WHXB20110127

理论与计算化学 上一篇    下一篇

二氢卟吩e6赖氨酸酰胺稳定性及电子光谱

万景柏1, 刘淑贞1, 潘树英1, 许旋1,2,3, 李旭1, 叶冰1   

  1. 1. 华南师范大学化学与环境学院, 广州510006;
    2. 广东省高校电化学储能与发电技术重点实验室, 广州510006;
    3. 华南师范大学, 电化学储能材料与技术教育部工程研究中心, 广州510006
  • 收稿日期:2010-07-24 修回日期:2010-10-26 发布日期:2010-12-31
  • 通讯作者: 许旋 E-mail:xuxuan@scnu.edu.cn
  • 基金资助:

    广东省教育部产学研项目(2010B090400184)和广东省自然科学资金项目(9151063101000037)资助

Stability and Electronic Spectra of Chlorin e6 Lysine Amides

WAN Jing-Bai1, LIU Shu-Zhen1, PAN Shu-Ying1, XU Xuan1,2,3, LI Xu1, YE Bing1   

  1. 1. School of Chemistry & Environment, South China Normal University, Guangzhou, 510006, P. R. China;
    2. Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation in Guangdong Universities, Guangzhou 510006, P. R. China;
    3. Engineering Research Center of Materials and Technology for Electrochemical Energy Storage, Ministry of Education of China, South China Normal University, Guangzhou 510006, P. R. China
  • Received:2010-07-24 Revised:2010-10-26 Published:2010-12-31
  • Contact: XU Xuan E-mail:xuxuan@scnu.edu.cn
  • Supported by:

    The project was supported by the Project of Ministry of Education of Guangdong Province, China (2010B090400184) and Natural Science Foundation of Guangdong Province, China (9151063101000037).

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摘要：

采用密度泛函理论在B3LYP/6-31G*水平上对二氢卟吩e6(简称e6)及设计的6个e6赖氨酸酰胺进行几何优化, 对优化构型用B3LYP/6-31G**法进行单点计算, 并用含时密度泛函理论LSDA/6-31G**方法计算电子吸收光谱. 结果表明, 赖氨酸的ε-NH2与e6连接的酰胺更稳定, 其中, 15位的乙酰胺Yε最稳定. 形成赖氨酸酰胺改善了e6 的水溶性, 有利于药物吸收. 各e6 赖氨酸酰胺的前线轨道集中于二氢卟吩环, 由于连接酰胺基侧链的二氢卟吩环平面性有所下降, 前线轨道能隙略为升高, 最大电子吸收波长相对于e6 蓝移16-39 nm, 但仍处于光动力治疗窗口“600-900 nm”. 酰胺链的构象对吸收波长影响较大, Yε三个较稳定构象中, 酰胺链垂直于二氢卟吩环的Yε1和Yε2的二氢卟吩环平面性较好, 最大吸收波长比酰胺链与二氢卟吩环近似平面的Yε红移53、50nm, 三者平均值较e6红移18 nm.

关键词: 密度泛函理论, 二氢卟吩e6赖氨酸酰胺, 电子吸收光谱, 稳定性

Abstract:

The geometric configurations of chlorin e6 and six designed e6 lysine amides were optimized using density functional theory at the B3LYP/6-31G* level. Based on the obtained minimum energy structure, a single point calculation was carried out at the B3LYP/6-31G** level. The electronic spectra of these compounds were calculated using time dependent density functional theory at the LSDA/6-31G** level. The results indicate that the e6 lysine amides, in which the carboxyl of e6 connects with the ε-NH2 of lysine, are more stable. Among them, the 15-acetamide Yε has the highest stability. The formation of lysine amides improves the water-solubility and leads to a slightly poor coplanarity of the chlorin macrocycle in e6. Therefore, the frontier orbital gaps of the e6 lysine amides are slightly higher than that of e6, causing the long wavelength absorption to a small blue-shift of 16-39 nm. The adsorption wavelength is still in the range of 600-900 nm for photodynamic therapy. Furthermore, the long wavelength absorption is strongly affected by the conformation of the molecule. By comparison with Yε, in which the lysine amide group and the chlorin macrocycle are almost coplanar, the planarity of the chlorin ring of Yε1 and Yε2, in which the lysine amide is almost perpendicular to the chlorin ring, is improved and results in red shifts of 53 nm and 50 nm for their long wavelength absorptions, respectively, the average adsorption wavelength of Yε, Yε1, and Yε2 is 18 nm larger than that of e6.

Key words: Density functional theory, Chlorin e6 lysine amide, Electronic absorption spectrum, Stability