柱撑型可见光响应MOFs的合成、表征及光催化性质研究

发布时间：2018-05-20 13:57

本文选题：金属有机骨架材料 + 柱撑结构　；参考：《东北师范大学》2016年硕士论文

【摘要】：金属有机骨架(Metal-Organic Frameworks, MOFs)材料作为一种新型的多功能分子基材料,受到了众多科研工作者的青睐。MOFs材料因其独特的结构和性能优势,如孔道结构规整、孔尺寸可调、比表面积大、有机配体及金属中心易功能化,在气体储存分离、荧光、磁性及催化等诸多领域展现了多样的功能性。近年来,开发具有可见光响应的MOFs材料以及扩展MOFs材料在人工光合成方面的应用逐渐成为研究的热点。本研究利用蒽基吡啶配体作为光捕获单元构筑了两个同构的具有宽谱带可见光响应的柱撑型MOFs材料-NNU-35(Zn/Cd)。通过单晶和粉末X射线衍射、热重、红外、紫外、稳态荧光、电子顺磁共振等表征手段,证实所制备MOFs材料受可见光激发形成的电荷空穴分离态以配体有机自由基的形式存在。利用这一光生电荷特性,在本论文第二章工作中我们将NNU-35(Zn)应用于可见光引发的原子转移自由基聚合(Atom Transfer Radical Polymerization, ATRP)反应中；而在第三章工作中,我们利用可见光活性的NNU-35(Cd)进行了光催化降解有机染料的研究。具体工作如下：1.利用交叉偶联反应合成了中性有机配体9,10-二(乙炔基吡啶)蒽；并选用1,4-对苯二羧酸作为辅助配体,与Zn2+以混配的方式构筑了新型的柱撑MOFs材料NNU-35(Zn)。分子式为{Zn(bdc)(L1)}2·DMF,结晶于单斜晶系,C2/c空间群。该结构以“柱撑”为特色,Zn2+和二酸形成二维层状结构单元,直线型双吡啶含氮配体在层间起到柱撑作用形成三维骨架结构。光谱研究表明,NNU-35(Zn)可在很宽的可见光范围内接受激发而产生光生电荷,由此我们创新性地尝试利用NNU-35(Zn)作为光敏剂诱导原子转移自由基聚合。实验表明,在室温可见光激发下,该MOFs材料可以有效的将二价铜配合物还原成具有催化活性的一价铜配合物,从而引发对丙烯酸酯类单体的可控聚合。结果显示所制得的聚合物具有较窄的分子量分布,同时链端活性基团可以有效保留,从而使聚合反应可以随着单体的加入继续进行。此外,光引发聚合反应的开启与停止能够通过光源的开启与关闭方便控制。该工作为光活性MOFs材料在光引发可控自由基聚合领域的应用提供了新的研究思路。2.利用柱撑策略,在不同的实验条件下通过金属取代制备了与NNU-35(Zn)同构的金属有机骨架材料NNU-35(Cd)。以NNU-35(Cd)作为光催化剂,我们研究了该MOFs光催化剂在水中对不同环境污染物-有机染料的光催化降解能力。实验结果表明,在可见光照射下,NNU-35(Cd)可以高效催化亚甲基蓝、罗丹明B等有机染料的降解。NNU-35(Cd)不仅具有较好的光催化活性,且能够多次循环利用。
[Abstract]:As a new type of multifunctional molecular materials, Metal-Organic frameworks (MOFs) materials have been favored by many researchers for their unique structural and performance advantages, such as regular pore structure, adjustable pore size and large specific surface area. Organic ligands and metal centers are functionalized and exhibit diverse functions in gas storage separation, fluorescence, magnetism and catalysis. In recent years, the development of MOFs materials with visible light response and the application of expanded MOFs materials in artificial light synthesis have gradually become a hot research topic. In this study, two isomorphic pillared MOFs materials with wide spectral band visible light response were constructed by using anthracenyl pyridine ligands as light trapping units. By means of X-ray diffraction, thermogravimetry, IR, UV, steady-state fluorescence and electron paramagnetic resonance (EPR), it was proved that the charge hole separation state formed by the visible light excitation of the prepared MOFs materials existed in the form of ligand organic free radicals. In the second chapter of this thesis, we apply NNU-35Zn to atom transfer radical polymerization (Transfer Radical Polymerization, ATRP) induced by visible light, while in chapter 3, we apply it to atom transfer radical polymerization. The photocatalytic degradation of organic dyes by visible light active NNU-35 (CD) has been studied. The work is as follows: 1. A new pillared MOFs material, NNU-35 MOFs, was synthesized by cross-coupling reaction, and a new pillared MOFs material, NNU-35ZnN, was synthesized by cross-coupling reaction, and 1 ~ (4) -p-phenylene dicarboxylic acid was used as the auxiliary ligand to construct a new pillared MOFs material, NNU-35 (acetylpyridine) anthracene. The molecular formula is {Znnbdcctadcl)} 2DMF, which crystallizes in the space group of C _ 2 / c in monoclinic system. The structure is characterized by "pillared" Zn2 and diacid to form a two-dimensional layered structure unit. The linear bipyridine nitrogen-containing ligands play a pillared role in the formation of three-dimensional skeleton structure. Spectroscopic studies show that NNU-35Zn) can be excited in a wide range of visible light to generate photogenerated charges. Therefore, we have innovatively tried to use NNU-35Zn) as a Guang Min agent to induce atom transfer radical polymerization. The experimental results show that the MOFs can effectively reduce the divalent copper complexes to monovalent copper complexes with catalytic activity under the excitation of room temperature visible light, thus initiating the controllable polymerization of acrylate monomers. The results show that the polymer has a narrow molecular weight distribution and the chain end active group can be effectively retained so that the polymerization can continue with the addition of monomer. In addition, the opening and stopping of the photoinitiated polymerization can be easily controlled by the opening and closing of the light source. This work provides a new research idea for the application of photoactive MOFs materials in the field of photoinduced controllable radical polymerization. In this paper, the metal-organic skeleton material NNU-35 / CdTe was prepared by metal substitution under different experimental conditions by using the pillared support strategy, which is isomorphic to NNU-35ZnN (NNU-35ZnN). Using NNU-35 CD) as photocatalyst, the photocatalytic degradation ability of MOFs photocatalyst for organic dyes in water was studied. The experimental results show that NNU-35 (CD) can efficiently catalyze the degradation of methylene blue, rhodamine B and other organic dyes under visible light irradiation. It not only has good photocatalytic activity, but also can be reused many times.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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