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

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。     

沙丁胺醇与三氟甲基丙烯酸印迹作用的理论研究

以沙丁胺醇(SAL)为印迹分子,三氟甲基丙烯酸(TFMAA)为功能单体,运用量子化学密度泛函理论(DFT)的LC-WPBE方法和6-31G(d,p)基组,模拟SAL印迹分子与TFMAA功能单体形成稳定复合物的构型,讨论了其稳定复合物的成键作用位点及数目、自然键轨道(NBO)电荷的转移及其反应的结合能,探讨了SAL与TFMAA相互作用的原理及分子印迹中溶剂的影响.模拟计算结果表明,SAL与TFMAA印迹比例为1∶4,以氯仿为溶剂时,合成的复合物能量最低,吸附性更强.     

三唑酮分子印迹预组装体系的分子模拟与吸附性能

以三唑酮为模板分子, 以丙烯酰胺(AM)、 丙烯酸(AA)、 甲基丙烯酸(MAA)和三氟甲基丙烯酸(TFMAA)为功能单体预组装了分子印迹聚合物体系, 采用半经验法和从头算法, 利用Hyperchem软件模拟了三唑酮与4种功能单体所组成的分子印迹预组装体系的构型、 能量、 反应配比及复合反应的结合能, 选择复合物结合能最高的功能单体用于分子印迹聚合物的合成. 采用密度泛函方法计算了模板与单体在不同致孔剂中的溶剂化能. 结果表明, 三唑酮与三氟甲基丙烯酸所形成复合物的作用力最强, 在非极性溶剂中溶剂化能最弱. 由预组装体系的差示紫外光谱法研究发现, 一分子三唑酮可与两分子三氟甲基丙烯酸在氯仿中形成氢键复合物, 与分子模拟的结果一致. 在最佳模拟条件下, 合成了三唑酮的印迹聚合物, 利用吸附等温线Langmuir和Freundlich模型研究了印迹聚合物的吸附行为及识别机理. 上述方法对于分子印迹体系的筛选及分子印迹聚合物性能的预测有重要的意义.     

有机磷神经毒剂分子印迹聚合物的模拟模板分子

采用DFT/B3LYP-D3(BJ)/6-31G(d,p)计算模拟方法分析探讨了双(对硝基苯基)磷酸酯(BNPP)替代对氧磷(PO)用作有机磷神经毒剂分子印迹聚合物(MIPs)模板分子模拟物的可行性. 通过对比BNPP和PO两种模板分子分别与各种功能单体形成的复合物的构型稳定性和结合能大小, 确认了以4-甲基丙烯酰胺基安替比林(MAAP)为第一功能单体、 甲基丙烯酸(MAA)为第二功能单体组成的双功能单体体系是最佳功能单体体系. 以BNPP为模板分子、 MAAP-MAA为单体体系、 乙二醇二甲基丙烯酸酯(EGDMA)为交联剂、 纳米二氧化硅为载体, 采用表面印迹技术制备了SiO₂@BNPP分子印迹聚合物, 并对聚合物的表面形貌和吸附性能进行了分析. 实验结果表明, 当n(BNPP)/n(MAAP)/n(MAA)/n(EGDMA)为1∶1∶4∶20时, MIPs的吸附容量最大可达19.03 mg/g, 对4-硝基苯酚(4-NP)的分离因子为17.50; MIPs能够快速吸附模板分子, 5 min即可达到吸附平衡量的92%, 动态吸附平衡时间仅为15 min, 重复使用5次后仍能保持良好的吸附能力; 吸附过程符合准二级动力学模型和Langmuir等温吸附模型, Scatchard方程分析表明MIPs中存在两类吸附作用位点. 实验结果与计算模拟结果的一致性表明, 计算模拟对有机磷神经毒剂MIPs的设计和研究具有一定的指导意义.     

计算机辅助三聚氰胺分子印迹聚合物的制备

以三聚氰胺(MAM)为印迹分子,丙烯酰胺(AM)、甲基丙烯酸(MAA)、N,N-亚甲基双丙烯酰胺(MBA)和衣康酸(IA)为功能单体,二乙烯基苯(DVB)、乙二醇双甲基丙烯酸酯(EGDMA)和三羟甲基丙烷三甲基丙烯酸酯(TRIM)为交联剂,采用量子化学密度泛函理论的长程校正方法模拟并探讨了MAM与4种功能单体的成键作用位点、成键数目、印迹反应摩尔比及印迹作用机理.依据结合能(ΔE)优化了功能单体和交联剂,并借助分子中原子理论(AIM)揭示了MAM与功能单体印迹作用的本质.计算结果表明,MAM通过氢键与4种功能单体以摩尔比1∶6进行印迹聚合,其中IA与MAM形成的复合物结合能最低,结构最稳定;与TRIM和EGDMA交联剂相比,DVB与MAM结合能最低,更适合作为MAM-IA印迹聚合物的交联剂.采用沉淀聚合法合成MAM分子印迹聚合物(MAM-MIPs)并测定其吸附性,当MAM与IA印迹摩尔反应比为1∶6时,以DVB为交联剂时制备的MAM-MIPs吸附性最好,其微球平均粒径为195 nm;Scatchard分析结果表明,在所研究的浓度范围内MIPs对印迹分子MAM的结合位点是等价的,其最大表观吸附量Qmax为20.79mg/g,离解平衡常数Kd为58.82 mg/L;与环丙氨嗪(CYR)、三聚氰酸(CYA)和三聚硫氰酸(TRI)在牛奶中的吸附量相比,MAM-MIPs对MAM表现出较强的特异吸附能力.     

巴比妥印迹聚合物的理论设计与实验性能评价

借助于Gaussian 09程序,运用杂化密度泛函M062X方法,以巴比妥(BAR)为印迹分子,分别以甲基丙烯酸(MAA)、丙烯酰胺(AM)、4-乙烯基吡啶(4-Vpy)及N,N’-亚甲基双丙烯酰胺(MBAD)为功能单体,模拟计算了BAR与不同功能单体间的相互作用,用氢键与结合能(ΔE)优化最佳功能单体.计算结果表明,MAA与印迹分子氢键数目最多,键长最短,ΔE最小,作用力最强,且最佳反应摩尔比为1∶6.采用沉淀聚合法合成BAR与MAA的分子印迹聚合物(MIPs)纳米微球,并对MIPs进行表征.结果表明,与AM,4-Vpy及MBAD相比,MAA与BAR形成的复合物稳定性与选择吸附性更高;乙腈致孔剂中合成的MIPs微球平均粒径为190 nm,分散性良好.Scatchard分析表明,在所研究的浓度范围内MIPs对BAR的结合位点是等价的,其离解平衡常数Kd与最大表观吸附量Qmax分别为63.3 mg/L和17.5 mg/g;热力学研究表明,BAR-MIPs对BAR的吸附为放热过程;BAR-MIPs对BAR的吸附量明显高于其对1,3-二甲基巴比妥酸(DMBA)、2-硫代巴比妥酸(TMB)和戊巴比妥钠(PBS)的吸附量,表现出较强的特异性吸附能力.     

计算机辅助设计三聚氰胺分子印迹聚合物

借助密度泛函理论(DFT)长程校正方法,以三聚氰胺(MAM)为印迹分子,甲基丙烯酸(MAA)为功能单体,分别以二甲基丙烯酸乙二醇酯(EGDMA)、三羟甲基丙烷三甲基丙烯酸酯(TRIM)及二乙烯苯(DVB)为交联剂,以乙腈(ACN)、甲醇(MT)、乙醇(EA)、甲苯(TL)、四氢呋喃(THF)及二甲基亚砜(DMSO)为溶剂,模拟了MAM与MAA单体分子印迹聚合物(MIPs)自组装体系的构型,讨论了MAM与MAA的成键作用位点,及其稳定复合物的印迹反应比例及印迹作用机理,依据结合能(△E)优化了交联剂和溶剂,并借助分子中原子理论(AIM)揭示了MAM与MAA印迹作用的本质.计算结果表明,MAM印迹分子三嗪环上的N与胺基上H均通过氢键与MAA单体进行印迹聚合反应,且在印迹反应比例为1∶6,以TL为溶剂时形成的MAM-MAA有序复合物结合能最低,构型最稳定;与TRIM及EGDMA交联剂相比,DVB与MAM结合能最低,更适宜作为MAM-MAA印迹聚合物的交联剂.本研究为MAM-MIPs合成时印迹比例、交联剂及溶剂的选择提供了理论依据.     

磁性介孔碳喹诺酮印迹聚合物的制备及性能研究

以恩诺沙星(ENR)和环丙沙星(CIP)为模板分子，Fe₃O₄/CO-CS-CH=CH₂、丙烯酰胺(AM)为双功能单体，乙二醇二甲基丙烯酸酯(EGDMA)为交联剂，偶氮二异丁腈(AIBN)为引发剂，乳液聚合法合成了磁性介孔碳喹诺酮印迹聚合物(MIPs)。采用X射线粉末衍射仪(XRD)、全自动比表面孔径分析仪(BET)、红外光谱(FTIR)、扫描电镜(SEM)和动静态吸附实验对其性能进行了研究。结果表明，成功合成了MIPs,为平均孔径4.678 nm的分散均匀球体，比表面积为452 m²/g;其对CIP和ENR的饱和吸附容量分别为40和29.4mg/g,高于非印迹聚合物(NIPs)对CIP和ENR的最大吸附容量(18.4和17.8 mg/g);MIPs对CIP和ENR的吸附符合准二级动力学模型；MIPs对CIP和ENR表现出良好的选择性吸附；MIPs稳定性好、使用寿命长。     

沉淀聚合法制备水杨酸分子印迹微球及其性能研究

以水杨酸(SA)为模板分子,丙烯酰胺(AM)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,利用沉淀聚合法制备了对水杨酸具有较高选择性与较高亲和性的分子印迹聚合物微球(MIPs)。用傅里叶红外光谱和环境扫描电镜表征印迹聚合物微球的结构和形貌,采用静态吸附法考察了水杨酸分子印迹聚合物微球的吸附性能。结果表明,当SA:AM:EDMA摩尔比为1:4:20时,得到的分子印迹聚合物微球粒径均一,球形度较好,对水杨酸具有较好的选择吸附性,最大表观结合量可达到52.42mg/g。     

硅胶表面苏丹红1分子印迹聚合物的制备与性能考察

本文以硅胶为载体,γ-(甲基丙烯酰氧基)丙基三甲氧基硅烷为表面修饰分子,苏丹红1为模板分子,2-乙烯吡啶为功能单体,N,N-亚甲基双丙烯酰胺为交联剂,偶氮二异丁腈为引发剂,制备了硅胶表面修饰分子印迹聚合物(MIPs)。红外光谱(FT-IR)验证了MIPs的成功制备,扫描电子显微镜(SEM)观察了MIPs的表面形貌,通过静态平衡吸附法考察了印迹材料的吸附动力学和饱和吸附量,并通过竞争性吸附对MIPs的吸附选择性进行了分析。     

Theoretical research on self-assembly system of molecularly imprinted polymers formed by melamine and trifluoromethacrylic acid

The long-range correction method (WB97XD) was applied to simulate the self-assembly system of the molecularly imprinted polymers via Gaussian 09 software. Melamine (MAM) was taken as the template molecule and trifluoromethacrylic acid (TFMAA) was taken as the functional monomer. The ethylene glycol dimethacrylate, divinylbenzene, pentaerythritol triacrylate, and trimethylolpropane trimethylacrylate were chosen as the cross-linking agents, respectively. The acetonitrile, methanol, dichloromethane, chloroform, toluene, ethanol, and dimethylsulfoxide were taken as solvents, respectively. The bonding situation, the geometry optimization of the different imprinting ratios, the binding energy, the molecular imprinting mechanism between MAM and TFMAA, and the influence of cross-linking agent as well as solvent have been studied. The detailed topological property was also applied to discuss the nature of the imprinting effect. The results indicate that MAM and TFMAA can form ordered compounds via hydrogen bond interaction. The melamine-molecularly imprinted polymers with a molar ratio of 1:6 have the lowest binding energy, the largest amount of hydrogen bonds, and the stable structure in toluene solvent. Divinylbenzene is the best cross-linking agent for the melamine-molecularly imprinted polymers in comparison with others. The study can provide a theoretical reference for the synthesis of the high selectivity melamine-molecularly imprinted polymers.     

Theoretical Researches on the Recognizing Characteristics of Atrazine Imprinted Polymers with Different Functional Monomers

As a widely used herbicide, the threat of atrazine to both environment and health of people has become the focus. Therefore, the research and analysis of atrazine are getting more important. In this work, the MIT was used to detect atrazine theoretically. Atrazine was taken as a template molecule. MAA, MMA and TFMAA were taken as the functional monomers, respectively. The geometry optimization, the nature of hydrogen bonds, the NBO charge, and the binding energies of the imprinted molecule with the functional monomers were investigated at the B3LYP/6-31g(d,p) level. Results indicated that atrazine had the strongest interaction with TFMAA. When the ratio of atrazine and TFMAA was 1:6, the amount of H-bond formed from atrazine and TFMAA was the largest. Moreover, TFMAA owned the largest binding energy with atrazine while MMA owned the smallest. The study is helpful to interpret experiment phenomena of molecular imprinting and select better functional monomers.     

Binding properties of 2,4,5-trichlorophenoxyacetic acid-imprinted polymers prepared with different molar ratios between template and functional monomer

Several molecularly-imprinted polymers binding the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were prepared with a molar ratio between the functional monomer and the template molecule in the pre-polymerisation mixture set between 1+2 and 20+1. The functional monomer used was 4-vinylpyridine (4-VP), the cross-linker was ethylene dimethacrylate, and the porogenic solvent was a mixture of methanol–water 3+1 (v/v). The polymers obtained were grinded, sieved and packed in 100 mm×3.9 mm HPLC columns. The effects of the mobile phase composition were evaluated by eluting the columns with acetonitrile–water mixtures. The results obtained indicate that column capacity, selectivity factor and the imprinting effect are controlled by ion-pair and hydrophobic interactions between the analyte and the stationary phase. In the full range of ratios considered, column capacity, selectivity factor and imprinting effect are inversely proportional to the molar ratio between the template molecule and the functional monomer.     

Theoretical design and selectivity researches on the enrofloxacin imprinted polymer

In this paper, enrofloxacin (ENRO) was chosen as the template molecule, 4-vinylpyridine (4-Vpy), acrylamide (AM), trifluoromethacrylic acid (TFMAA), and 2-hydroxyethyl methacrylate (HEMA) were selected as the functional monomers, with the following cross-linking agents, ethylene glycol dimethacrylate (EDMA), pentaerythritol triacrylate (PETA), and trimethylolpropane trimethacrylate (TRIM). The stable complex configurations formed by ENRO and four monomers at the molar ratio of 1:1 were calculated using the density functional theory at the B3LYP/6-31G(d,p) level. Their natural bond orbital charges and the action sites were discussed to screen the appropriate functional monomer. The optimal molar ratio of template–monomer complex and the effects of cross-linking agent were investigated. The nature of the imprinting interaction was also researched via the infrared spectrum. The results reveal that the complex formed from ENRO and TFMAA has the strongest hydrogen bond interaction. When the molar ratio is 1:7, the complex has the most stable configuration. Owning to the weakest interaction between EDMA and ENRO, and the strongest interaction between EDMA and TFMAA, EDMA is considered as the suitable cross-linking agent, in comparison with PETA and TRIM for ENRO-MIPs. After the removal of ENRO molecule, the most stable ENRO-TFMAA complex owing to the better binding capacity to ENRO is compared with its structural analogues (ciprofloxacin, sparfloxacin, pefloxacin, ofloxacin, and sarafloxacin). This study provides a reliable theoretical guidance for the preparation of new ENRO-MIPs.     

Configurational Simulations and Theoretical Calculations of Molecularly Imprinted Polymers of Histamine and 2‐(Trifluoromethyl)acrylic Acid Based on Computational Chemistry

In this article, we provide a theoretical discussion on the interactions between a template molecule and functional monomer(s) in the preparation of molecularly imprinted polymers (MIPs ). Density functional theory (DFT ) was used to compute the 3D structures, natural bond orbital, and binding energy in the template–monomer(s) complexes. Histamine (HA ) and 2‐(trifluoromethyl)acrylic acid (TFMAA ) were, respectively, selected as the template and the monomer. The computational process was performed according to B3LYP method with 6‐311 + (d,p) basis set under the different HA–TFMAA ratios from 1:1 to 1:10. The computational results show that the HA–TFMAA complex at the ratio of 1:5 yields no consequence. Furthermore, the HA–TFMAA complex at the ratio of 1:5 allowed the minimum binding energy and the steadiest condition, with four hydrogen bonds. Configurational simulations and theoretical calculations of the template–monomer complex can be used as an appropriate guiding tool for manufacturing MIPs with high specificity and selectivity, thereby avoiding repeated experiments and wastage of substantial time and investment.     

酚酞分子印迹聚合物的制备及特异吸附性能

以泻药酚酞为模板分子,4-乙烯基吡啶为功能单体制备了模板分子和功能单体不同比例的一系列酚酞分子印迹聚合物。利用扫描电镜对聚合物进行了表面形态分析,采用静态平衡实验法研究了聚合物对模板分子及其类似物的吸附行为和选择性识别能力。实验结果表明,所制备的分子印迹聚合物,吸附 3 h 后基本接近最大吸附量,其中模板分子、4-乙烯基吡啶和交联剂的摩尔比为 1∶6∶20的MIP2的印迹因子为 2.30,效果最佳。Scatchard 分析表明, 在所研究的浓度范围内,吸附过程存在两类结合位点,一类高亲和力结合位点的离解常数为Kd1= 0.63 mmol/L,最大表观结合量 Qmax1 = 25.4 umol/g,另一类低亲和力结合位点的离解常数为 Kd2 =3.5 mmol/L,最大表观结合量 Qmax2 = 61.9 umol/g,通过与酚酞类似物质在酚酞分子印迹聚合物上的吸附行为比较,表明对酚酞具有很好的选择性吸附。     

Optimization of Functional Monomer Content in Protein‐Imprinted Polymers

Abstract

We have prepared synthetic materials having binding specificity toward lysozyme using molecular imprinting. The lysozyme‐imprinted polymers were prepared on silica beads using acrylic acid, acrylamide, and N,N′‐methylenebisacrylamide. The molar ratio of acrylic acid to the template affected the selectivity and the maximum binding specificity was yielded with the molar ratio of 5 to 1 (acrylic acid/template). No binding specificity toward lysozyme was observed when there was no acrylic acid, and the binding specificity decreased when the amount of acrylic acid was high. The functional monomer‐template ratio indicated in this study could be useful for improving the binding specificity in molecular imprinting of proteins.     

Preparation of a stoichiometric molecularly imprinted polymer for auramine O and application in solid‐phase extraction

We describe a stoichiometric approach to the synthesis of molecularly imprinted polymers specific for auramine O. Using the stoichiometric interaction in molecular imprinting, no excess of binding sites is necessary and binding sites are only located inside the imprinted cavities. The free base of the template was obtained to facilitate the interaction with the monomers. Itaconic acid was selected as the functional monomer, and stoichiometric ratio of the interaction with the free base was investigated. The molecularly imprinted polymer preparation conditions such as cross‐linker, molar ratio, porogen were optimized as divinylbenzene, 1:2:20 and chloroform/N,N‐dimethylformamide, respectively. Under the optimum conditions, a good imprinting effect and very high selectivity were achieved. A solid‐phase extraction method was developed using the molecularly imprinted polymers as a sorbent and extraction procedure was optimized. The solid‐phase extraction method showed a high extraction recovery for auramine O in its hydrochloride form and free form compared to its analogues. The results strongly indicated that stoichiometric imprinting is an efficient method for development of high selectivity molecularly imprinted polymers for auramine O.     

槲皮素金属配位分子印迹聚合物的识别性能

以槲皮素与Zn(Ⅱ)的配合物为模板,在甲醇溶液中制备金属配位分子印迹聚合物.通过紫外光谱研究了槲皮素与Zn(Ⅱ)的配位方式及配位比,验证了槲皮素、Zn(Ⅱ)和4-乙烯基吡啶之间的三元配位作用.利用红外光谱对产物的结构进行了表征.用平衡结合实验考察了功能单体及交联剂用量对聚合物吸附性能的影响,优化了聚合物的反应配比.同时对系列印迹聚合物的识别体系进行了考察.结果表明,槲皮素-Zn(Ⅱ)模板印迹聚合物对槲皮素-Zn(Ⅱ)的配合物表现出明显的吸附选择性和特异性,对槲皮素结构类似物芦丁和柚皮素的吸附选择性较差,分离因子分别为3.21和1.91.