【作者】 张美；

【导师】 袁黎明；

【作者基本信息】 华东师范大学 ， 分析化学， 2014， 博士

【摘要】 金属-有机骨架化合物(Metal-Organic Frameworks, MOFs)作为一种新型的功能材料,因其具有高的比表面积、丰富的拓扑结构、持久性的孔结构以及可修饰的孔道表面等特点,使其在气体储存、催化剂、吸附分离、传感等许多领域具有广阔的应用前景。手性金属-有机骨架材料作为MOFs发展的一个重要部分,由于具有多孔的功能位点和手性,使其在不对称合成和手性选择分离领域备受人们的青睐。目前,手性MOFs在手性分离中还主要集中在液相吸附分离,而在色谱分离领域将其用作色谱固定相进行手性分离的报道还比较有限。据我们所知,手性MOFs用于液相色谱固定相进行手性分离的报道仅有三篇,其中一篇是将Bn-ChirUMCM-1仅用于1-苯基乙醇的分离且伴随较低的分辨率,而另外两篇分别将[Zn2(bdc)(L-lac)(dmf)]·DMF(bdc=p-benzenedicarboxylic acid, L-lac=L-lactic acid)和(R)-MOF-silica都仅用于烷基芳基亚砜类物质的分离,三者均显示了较窄的应用范围。本论文旨在探索手性MOFs用作高效液相色谱固定相的分离性能,以便开发具有较高手性选择性的固定相,从而拓展手性MOFs在色谱手性分离领域的应用。本文合成了具有不同手性结构特征的手性MOFs,并将其分别用作高效液相色谱固定相进行外消旋化合物的分离,讨论了流动相的组成、柱温以及溶质含量等对手性MOFs固定相分离性能的影响。另外,通过比较目前已知的手性MOFs在高效液相色谱固定相中的应用情况,小结了在高效液相色谱固定相上具有手性识别能力的手性MOFs的主要特点以及容易在手性MOFs固定相上实现分离的外消旋化合物类型。论文主要包括以下内容：第一章为绪论,概述了手性的基本概念、手性拆分的重要性和手性拆分的主要方法：同时对高效液相色谱法、高效液相色谱手性固定相的发展和主要种类进行了介绍：另外综述了金属一有机骨架材料的发展、合成和在色谱分离领域的应用。最后,提出了本论文的研究目的和意义。第二章合成了一种具有三维螺旋结构的介孔手性金属-有机骨架材料[(CH3)2NH2][Cd(bpdc)i.5]·2DMA (bpdc=4,4’-biphenyldicarboxylate, DMA=N,N’-Dimethylacetamide),将该晶体活化以除去客体分子,经粉末XRD和热重分析表明其活化后结构没有变化。把活化后的晶体研磨并用溶剂悬浮法获得粒径约为5-10μm的颗粒,采用高压匀浆法在40MPa下进行装柱,并用该柱分离多种外消旋化合物。实验结果表明,该柱对醇类、酮类、酚类、黄酮、胺类等10种手性化合物表现了较好的手性识别能力。说明此晶体活化后具有较好的手性识别能力,证明了手性MOFs应用于高效液相色谱手性固定相的可行性,其为手性分离科学研究探索了新的途径。第三章合成了颗粒适中且相对均匀的具有二维手性层面结构的均一手性MOF [Zn2(D-Cam)2(4,4’-bpy)]n (D-Cam=D-Camphoric acid,4,4’-bpy=4,4’-bipyridine),采用湿法装柱制备高效液相色谱手性柱并用于外消旋化合物的分离,讨论了柱温、溶质含量以及流速等对手性分离性能的影响。实验结果表明,该柱对醇类、酚类、酮类、醛类、胺类和手性化合物等9种手性化合物表现了较好的手性识别能力。显示了该晶体填充柱对外消旋化合物具有较好的手性识别能力,手性MOFs能方便地应用于高效液相色谱手性固定相。第四章合成了相对较纯的具有开放手性孔道的的均一手性MOF[Cd2(D-cam)3]·2Hdma·4dma·2H2O (dma=dimethylamine),并将其用作高效液相色谱手性固定相用于外消旋化合物的分离,同时探讨了流动相的组成、柱温和溶质含量等影响外消旋化合物在该固定相上手性分离的关键因素。该固定相对多种手性化合物尤其是对(±)-1-(1-萘基)-乙醇表现了较好的手性识别能力,其分离度(RS)高达4.55,这使[Cd2(D-cam)3]·2Hdma·4dma·2H2O可能成为用于(±)-1-(1-萘基)-乙醇手性分离的有力备选材料。该实验结果表明[Cd2(D-cam)3]·2Hdma·4dma·2H2O填充柱对外消旋化合物具有较好的手性识别能力。第五章合成了一种具有三维六连接自穿插结构的均一手性MOF[Cu2(D-Cam)2(4,4’-bpy)]n,将其制备成高效液相色谱固定相同时用于位置异构体和手性化合物的拆分,并讨论流动相的组成、柱温和溶质的含量等对分离位置异构体和手性化合物的影响。结果显示有10种位置异构体在该固定相上得到拆分,表明该固定相对位置异构体具有较好的分离能力：而作为手性固定相,该MOFs对六种手性化合物(含醇类、酚类和酮类)具有较好的识别能力。表明该手性MOFs同时对位置异构体和外消旋化合物都具有较好的识别作用,说明可以将手性MOF填充柱同时用于手性分离和位置异构体分离。该研究拓展了手性MOFs在色谱分离领域的应用。第六章分别合成了具有不同手性结构特征的四种手性MOFs.即[{Cu(sala)}小[Cd(LTP)2]n、γ-CD-MOF和[Zn2(bdc)(L-lac)(dmf)]·DMF),并将它们用于高效液相色谱固定相进行位置异构体(仅[{Cu(sala)}n]CSP)和外消旋化合物的拆分。四种手性MOFs对所测外消旋化合物的手性识别能力不同,其中具有三维螺旋结构的[{Cu(sala)}n]固定相分别对3种位置异构体和7种外消旋体实现了不同程度的分离,但是剩余三种的手性识别能力相对较差。因此手性MOFs的组成和结构不同,其手性识别能力也不同。第七章以本论文研究的内容为主,同时收集我们课题组其他合作者的相关研究,对MOFs拆分外消旋化合物工作进行了一定的收集、整理、分析和比较,力争总结出一些规律,以便使金属-有机骨架材料的手性分离认识进一步深入。更多还原

【Abstract】 Metal-organic frameworks (MOFs) as a new generation of functional molecular materials, have shown intriguing applications in gas storage, catalysis, separation, sensor and many other fields due to their unusual properties, such as high surface area, rich topologies, permanent microporous, availability of outer-surface modification and so on. Being another important section of MOFs, chiral MOFs also have attracted much attention in asymmetric catalysis and separation because of their porous functionalities and chirality. Chiral MOFs are typically used in adsorption separation, while a few of them were reported for chiral stationary phases in chromatography. To the best of our knowledge, there are only three attempts to utilize chiral MOFs in high-performance liquid chromatography (HPLC). Bn-ChirUMCM-1was only used for1-phenylethanol with low resolution,[Zn2(bdc)(L-lac)(dmf)]’DMF (bdc p-benzenedicarboxylic acid, L-lac=L-lactic acid) and (R)-MOF-silica were specially used for chiral alkyl aryl sulfoxides, all of them showed narrow scope in enantioseparations. In order to explore chiral MOFs as a new kind of chiral stationary phases, they were studied for HPLC chiral separation in this dissertation.Chapter one was the preface. Firstly, the basic concepts of chirality, the important of chiral separations and the chiral separation methods were stated. Secondly, HPLC and chiral stationary phases were introduced. Thirdly, the development, synthesis, and application of MOF were reviewed, especially for eanti﹕eparations in chromatography. Finally, the goals and the significances of this dissertation were also illustrated here.An unusual3-D chiral nanoporous MOF was synthesized in chapter2. X-ray powder diffraction and TG analysis of [(CH3)2NH2][Cd(bpdc)1.5]-2DMA (bpdc=4,4-biphenyldicarboxylate, DMA=N,N’-Dimethylacetamide) were employed to demonstrate that DMA molecules can be removed without breaking the open structure. The crystals of [(CH3)2NH2][Cd(bpdc)1.5] with an average size of5μm were obtained by the solvent suspension. Then, the prepared crystals were slurry-packed into a stainless steel empty column under40MPa. Ten racemates including alcohol, phenol, flavone, ketone, and amide etc. were successfully separated on this column. The experimental results showed that [(CH3)2NH2][Cd(bpdc)1.5] possesses excellent recognition ability for various racemates, the enantioseparations on chiral MOFs is practicable, which opens a new gateway in chiral separation science.In chapter3, a chiral MOF [Zn2(D-Cam)2(4,4’-bpy)]n (D-Cam=D-Camphoric acid,4,4’-bpy=4,4’-bipyridine) with2-D homochiral layers was convenient used as chiral stationary phase with suitable particle size and uniform cubic shaped for enantioseparations. The influence of column temperature, analytes mass and flow rate on enantioseparations was discussed. A wide range of enantiomers such as alcohol, aldehyde, phenol, ketone, amide, and chiral drug etc. were successfully separated with lower column pressure. The convenient and optical selectivity on the naturely chiral MOF column can promote the application of chiral MOFs use as stationary phase for chiral discrimination.A homochiral MOF [Cd2(D-cam)3]·2Hdma·4dma·2H2O (dma=dimethylamine) with open chiral channels was synthesized before used as a new chiral stationary phase for high-performance liquid chromatographic enantioseparation in chapter4. Many kinds of enantiomers were successfully separated on [Cd2(D-cam)3]·2Hdma·4dma·2H2O packed column, especially for (±)-1-(1-naphthyl)ethanol with a high resolution (RS=4.55) which possibly make this chiral MOF as a promising candidate for specific separation of some enantiomers. When racemate of (±)-1-(1-naphthyl)ethanol was separated on the packed optical resolution column, the retention and the selectivity of analyte were influenced by the mobile phase composition, column temperature, and analytes mass.Chapter5focused on exploring the chromatographic characteristic of a homochiral MOF [Cu2(D-Cam)2(4,4’-bpy)]n with3-D six-connected self-penetrating architectures for the separations of positional isomers and chiral compounds. Some impact factors (mobile phase composition, column temperature, and analytes mass) for enantioseparations on this chiral column also had been investigated. Fortunately, besides six racemates of alcohol, phenol, and ketone compounds were successfully discriminated by this chiral stationary phase, ten useful positional isomers were also analyzed on this packed column.[Cu2(D-Cam)2(4,4’-bpy)]n exhibited good selectivity for positional isomers and enantiomers. Therefore, it is practicable that the separation of positional isomers and enantiomers are carried out on the chiral MOF column.Chiral MOFs ([{Cu(sala)}n],[Cd(LTP)2]n, y-CD-MOF, and [Zn2(bdc)(L-lac)(dmf)]-DMF) were packed into four stainless steel empty columns, respectively (chapter six). However, those CSPs possessed different chiral property to give different resolution abilities.[{Cu(sala)}n] with3-D chiral channel framework had separated three positional isomers and seven racemates, whereas another MOFs hadn’t separated for the tests. Thus, the chiral MOFs with different composition and structure may lead to different chiral recognition abilities.In order to gain further insight into the enantioseparation of chiral MOFs, chapter seven gave some collection, analysis, and comparison of the data coming from this dissertation, our group’s work and published reports so that the chiral MOFs as stationary phases will further be utilized in the liquid chromatography.更多还原