齐墩果酸分子印迹聚合物预组装体系的分子模拟及聚合物制备

Computational Strategies for the Design and Study of Oleanolic Acid-imprinted Prepolymerization Mixtures

以齐墩果酸(OA)为模板分子,三氟甲基丙烯酸(TFMAA)、α-甲基丙烯酸(MAA)、丙烯酰胺(AM)、4-乙烯基吡啶(4-VP)为功能单体,三氯甲烷、四氢呋喃、乙醇、甲醇和丙酮为溶剂,基于量子化学密度泛函理论(DFT)和ONIOM方法,采用Gaussian09软件模拟计算了模板分子与不同功能单体的印迹聚合物预组装体系的构型,探讨了模板分子与功能单体在不同印迹比例时所形成复合物的成键情况以及反应过程中的结合能,并采用自洽反应场极化连续模型(CPCM)计算了功能单体与模板分子在不同溶剂中的溶剂化能。结果表明,TFMAA与模板分子OA以1:1摩尔比形成复合物的结合能ΔE最高(-70.99kJ·mol^(-1)),结构最稳定,模板分子和功能单体在三氯甲烷中的溶剂化能最小。同时,采用实验方法验证模拟结果,并利用扫描电镜、傅里叶红外光谱仪和静态吸附实验对印迹聚合物的形貌、化学基团和吸附性能等进行表征。结果表明,模拟结果与实验结果完全一致,计算机模拟对分子印迹体系的筛选和机理研究提供了理论依据。

In this study,the pre-organization system of molecularly imprinted polymer with oleanolic acid as template,2-（trifluoromethyl） acrylic acid （TFMAA）,methacrylic acid （MAA）,acrylamide （AM）,and 4-vinylpyridine （4-VP） as functional monomers,chloroform,tetrahydrofuran （THF）,ethanol,methanol,and acetone as solvents was studied by computational methods.The density functional theory （DFT） and ONIOM method was used to investigate the geometry optimization,active sites,natural bond orbital charges,binding energies of the imprinted molecule.The solvation energy of template and monomer in different solvent was calculated using self-consistent reaction field of polarizable continuum model approach （CPCM）.The theoretical results showed that the compound of the ratio of OA-TFMAA （1∶1） had the highest binding energy （-70.99kJ·mol^-1） and the most stable structure,and the solvation energy for template and monomer in chloroform were lower than that in THF,ethanol,methanol,and acetone.The corresponding experimental results were used to verify the simulation results.Meanwhile,the polymers were characterized by using scanning electron microscopy,fourier transform infrared spectrum,and adsorption experiments.The experimental result is completely consistent with the theoretic analysis,which indicates that the computer simulations can provide a route to more efficient MIP design strategies.