多巴胺构象结构和性质的密度泛函理论研究  

Density functional theory study on the conformations and properties of dopamine

作　　者：黄旭慧[1] 孙晓玲[1] 蔡跃飘[1] 王朝杰[1] 

机构地区：[1]温州医学院药学院,浙江温州325035

出　　处：《温州医学院学报》2013年第1期15-21,共7页Journal of Wenzhou Medical College

基　　金：国家自然科学基金资助项目(21177098);温州市科技局科研基金资助项目(Y20080103)

摘　　要：目的:研究多巴胺(DA)最稳定构象DA1在气相、油相环己烷和水相中的构象及其性质变化。方法:用B3LYP/6-311++G(2d,p)对DA不同构象进行全优化,得到最稳定的DA1,再以其二面角φ(C4-C9-C10-N11)为变量,研究在0°～360°范围内不同环境中DA1的构象结构和性质变化,溶剂效应用PCM考虑。采用TD-B3LYP/6-311++G(2d,p)计算UV-Vis谱,并在OPBE/6-311++G(2d,p)//B3LYP/6-311++G(2d,p)水平上计算1H、13C-NMR。结果:φ=180°时,DA1在三相中的能量最低。当0°≤φ≤60°时,水相中DA1构象转变能垒最高,而60°≤φ≤120°范围内则是最低。不同环境中,DA1构象变化的势能曲线遵循正弦函数变化。随着溶剂极性增大,DA1中O-H、N-H和C-N键长逐渐增大。水相中DA1的构象变化引起UV-Vis变化复杂,而气相中最大吸收峰对应单一的HOMO与LUMO+1之间的电子跃迁。环境极性增加,1H-NMR的化学位移值增大而增大,而13C-NMR的化学位移呈逐渐降低。结论:溶剂极性影响DA1的构象变化的能垒高低,随φ的增大,DA1的构象结构和性质均呈现一定的变化规律。Objective： To study the changes of conformations and properties for the most stable conforma-tion DA1 of dopamine （DA） in gas, cyclohexane, and water phases. Methods： Different initial conformations of DA were optimized fully at the B3LYP/6-311 ＋＋G （2d, p） level. The dihedral angle dp （C4--C9-C 10-N 11） in DA 1 was varied at 5 ° step size increased in 0-360 ° range to study the conformation and properties with the polarizable continuum model （PCM）. TD-B3LYP/6-311＋＋G （2d, p） were used to obtain UV-Vis absorption spectra, and calculated XH,13C-NMR at the OPBE/6-311＋＋G （2d, p）//B3LYP/6-311＋＋G （2d, p） level. Results： The lowest energy conformer was qb =180 ° in three phases. As 0 ° 〈 qb 〈 60 °, the rotation energy barrier of DAI in water phase was the highest, but as 60 ° 〈 qb 〈120 °was the lowest. In the different solvents, the potential energy curves of DA1 conformational isomerization could be fitted fairly well by sine function. With the increase of solvent polarity, the bond length of O-H, N-H and C-N elongated slightly. The UV-Vis spectra of DA1 in water was the most changeful, however, its the maximum peak in gas corresponding to HOMO to LUMO＋I electron transition. 1H-NMR chemical shift values increased when solvent polarity raised, while 13C-NMR chemical shift values reversed. Conclusion： The energy barrier of the conformational isomerization of DA1 is affected by solvent polarity. With the increase of qb, the conformations and properties of DA1 present somewhat regular pattern.

关 键 词：多巴胺 B3LYP 构象异构 溶剂效应 

分 类 号：O641[理学—物理化学]