共价有机骨架材料的合成及应用

共价有机骨架材料(Covalent organic frameworks,COFs)是有机单体通过可逆共价键连接形成的晶型有机多孔材料.自2005年首例COFs报道以来,大量新型COFs应运而生.COFs具有质量轻、密度低、结构规整、孔道结构可调、比表面积大、化学稳定性高的优势,在生命科学、环境保护和能源化工等方向具有巨大的应用潜力.由于功能化的COFs易实现不同物质在其内部的传输,目前研究人员已经成功将大量COFs应用于气体的吸附和分离与存储、催化剂、药物传递、有机电子器件和选择性分离薄膜等领域并取得了丰硕的研究成果.大量研究表明,COFs是高效存储CO2、H2和CH4的多孔材料,并且也可以作为催化剂载体,甚至可以直接作为催化剂用于催化各种化学反应.COFs的水分散度高且不会对细胞产生毒性,对布洛芬、5-氟尿嘧啶和槲皮素等药物表现出高效的负载和释放性能.2D COFs的π阵列型结构孔道高度规整,容易形成良好的载流子传导路径,可作为半导体元器件、超级电容器和质子交换膜等有机电子器件的理想候选材料.由于其高度有序且稳定的纳米孔道结构特性,2D COFs还可作为性能良好的纳滤薄膜,以高效分离溶剂中的染料分子.本文总结了COFs的各种特性并概述了COFs的结构设计、功能化和合成方法,综述了COFs在气体吸附与存储、催化剂、药物传递、有机电子器件和选择性分子筛薄膜领域的应用进展,并对其发展的新趋势进行了展望.     

金属有机骨架在水环境治理领域的应用

金属有机骨架(MOFs)由金属节点与有机配体通过配位键连接而成的多孔网络框架材料,其具有高比表面积和孔隙率以及丰富可调的孔结构,使其成为广泛关注的研究热点之一。对近几年来MOFs在水环境治理领域,特别是对重金属离子和有机污染物治理领域的研究进展进行了综述;讨论了MOFs通过构件分子和孔结构的修饰与调控对水中污染物的吸附机理;指出作为吸附剂MOFs最大的优越性在于,可根据目标污染物分子、离子的特点,在MOFs中引入不饱和金属位点和各种官能团和对骨架结构、孔隙大小和孔表面物理化学特性进行调控,以达到增大吸附选择性、增加吸附容量、提高吸附速率的目的,在吸附法去除重金属离子和有机污染物治理领域的有很大的潜力。同时,在合成MOFs时采用环境友好的构建分子,避免二次污染,并逐步降低成本。     

共价有机骨架储氢性能的研究进展

共价有机骨架(COFs)具有良好的热稳定性,大的表面积,高的孔隙率和极低的密度,因而显示出优异的储氢性能。重点介绍了COFs储氢性能的研究进展和目前存在的问题,提出了今后的研究重点和发展方向。     

金属有机骨架材料在光催化反应中的应用研究进展

环境问题和能源危机的是当今人类社会面临的两大重要问题。光催化技术被认为是解决环境问题和能源危机的有效途径之一。光催化技术利用的关键就是光催化材料的开发。金属有机骨架材料(Metal-organic frameworks,MOFs)是由金属或金属簇与有机配体构筑的一类具有周期性网络结构的新型多孔晶体材料,具有比表面积大、孔道结构规整、孔尺寸可调、催化活性位丰富等优点,被广泛应用于气体存储、气体分离、多相催化、半导体、仿生矿化等多个领域。近十几年来,众多科研工作者尝试将MOFs材料用于光催化反应,并取得了许多优秀的科研成果。尤其是近几年,MOFs在光催化领域的应用受到了越来越多科研工作者的关注。主要综述了近几年MOFs作为光催化剂在催化产氢、CO_2还原、烷基化反应、有机物氧化、有机还原、交叉脱氢偶联反应和去除环境污染物等方面的应用研究进展,并对未来MOFs光催化材料的发展提出了建议。     

共价有机骨架材料的CO2捕获性能研究

共价有机骨架材料(COFs)作为一类新型的纳米多孔晶体材料,由于具有表面积大、结构多样性、永久孔隙率高和热稳定性高等优点,在CO_2捕获性能方面表现出优异的应用前景。简要介绍了COFs的合成及表征方法、描述CO_2捕获性能的物理量。综述了几类COFs对CO_2捕获性能的研究进展,如含硼类、三嗪类和亚胺类COFs,并对它们的捕获性能进行了比较和总结,指出其优点和局限性。最后对未来的研究方向和发展趋势进行了展望。     

双金属类MOF材料的制备及应用

金属有机骨架(MOFs)是一种多孔材料,具有较高的孔隙率、大的比表面积和均匀分散的活性位点等特性,得到了研究者的广泛关注。主要介绍了双金属类MOFs材料的制备方法,及其在气体储存和非均相催化等领域的应用。其中,着重介绍了掺杂的金属活性组分对二氧化碳(CO_2)的吸附及苯酚催化加氢的作用机理,并展望了未来的发展前景。     

多级孔金属有机骨架材料的合成及应用研究进展

通过对目前多级孔金属有机骨架材料MOFs的合成方法及其在吸附、催化、传感领域应用进行介绍与总结,对多级孔MOFs材料的合成方法与应用前景进行评述与展望。     

金属有机骨架材料在气体吸附与分离中的应用研究进展

金属有机骨架材料(MOFs)因具有超高比表面积、较大的孔隙率、多样化且可调的孔道结构及相对温和的制备条件等优势,目前已成为化学和材料等学科的研究热点之一。概述了MOFs材料的制备方法及其用于气体(含碳、含氮及含硫)吸附与分离方面的研究进展,并对其在该方面今后的发展趋势和应用前景进行了展望。     

金属有机骨架材料固定化酶的研究进展

金属有机骨架材料(MOFs)凭借其较高的比表面积和孔体积、可设计和调控的孔径及结构,以及化学和热稳定性等特点,克服了传统固定化酶载体的孔径尺寸不可控、制备成本高、酶浸出、产物稳定性差等不足,近年来成为一类新型酶固定化载体.首先,本文分类总结了MOFs固定化酶的合成策略,包括后合成包装和从头合成封装(仿生矿化、共沉淀和机械化学封装);然后进一步介绍了多级孔MOFs的孔道设计策略及其固定化酶体系.这种具备分级孔道结构的MOFs用于固定化酶既可以保证酶的较高负载率,又能提高酶催化底物的扩散速率;此外,本文还介绍了MOFs共固定化多酶体系及具有类酶特性的仿生MOFs固定化酶方面的研究.MOFs特有的孔道结构可以大大缩短酶与底物之间的扩散距离,同时充分利用了酶级联反应的中间产物,可以显著提高酶催化活性;文章最后总结了MOFs固定化酶复合材料在生物传感和污染物催化净化领域的主要应用,提出了MOFs固定化酶研究中的一些瓶颈问题,以期为该材料的进一步研究和未来产业化提供借鉴和参考.     

基于MOFs超级电容器电极材料研究进展

超级电容器作为一类新型能源转化存储元件,在能源需求迫切增长的今天备受瞩目,而电极材料的研发则对超级电容器最终性能起着至关重要的作用。金属有机骨架(MOFs)因具备比表面积可观,活性位点丰富,孔径分布可控,易于合成等显著优势,可作为一种优良的电极材料。分别就MOFs, MOFs衍生物以及MOFs复合材料在超级电容器领域的最新研究进展进行了阐述,并展望了MOFs基电极材料未来的研究方向。     

Non-carboxylate based metal-organic frameworks (MOFs) and related aspects

The metal-organic frameworks, in recent years, show a variety of new developments that includes new methods of preparation, post synthesis modifications and novel class of compounds. Though most of the developments happened in the carboxylate based family of compounds, the other related systems are also equally interesting. In this article, we have highlighted some of the developments that have taken place in the family of non-carboxylate metal-organic frameworks. We have also highlighted some of the recent attempts at modifying the surfaces and pores of the MOFs by careful chemical manipulations.     

Characterization of mixing performance in a microreactor and its application to the synthesis of porous coordination polymer particles

Here we quantitatively evaluated the mixing performance of a tailor-made microreactor with central-collision type through the iodide/iodate chemical test reaction, and applied the microreactor to the synthesis of zeolitic imidazolate framework-8 (ZIF-8), which is a subclass of porous coordination polymers (PCPs) or metal organic frameworks (MOFs). The chemical test reaction demonstrated excellent mixing performance of the microreactor with a characteristic mixing time shorter than 1 ms, which is approximately 100 times faster than those of a batch reactor and a millimeter-sized Y-shaped mixer. Taking advantage of the rapid and uniform mixing, the microreactor successfully produced ZIF-8 particles with high reproducibility by simply mixing aqueous solutions of zinc nitrate and 2-methylimidazole. The synthesis at room temperature resulted in ZIF-8 particles with chamfered cube shape, while a lower temperature of 5 °C produced raspberry-type spherical particles. We confirmed that prepared ZIF-8 particles have BET surface area of ～1500 m²/g and exhibit the gate adsorption behavior caused by the structural transition of the ZIF-8 framework.     

Controlling Monomer Feeding Rate to Achieve Highly Crystalline Covalent Triazine Frameworks

The synthesis of highly crystalline covalent triazine frameworks (CTFs) with ultrastrong covalent bonds (aromatic C?N) from the triazine linkage presents a great challenge to synthetic chemists. Herein, the synthesis of highly crystalline CTFs via directly controlling the monomer feeding rate is reported. By tuning the feeding rate of monomers, the crystallization process can be readily governed in a controlled manner in an open system. The sample of CTF‐HUST‐HC1 with abundant exposed {001} crystal facets has the better crystallinity and thus is selected to study the effect of high crystallinity on photoelectric properties. Owing to the better separation of photogenerated electron–hole pairs and charge transfer, the obtained highly ordered CTF‐HUST‐HC1 has superior performance in the photocatalytic removal of nitric oxide (NO) than its lesser crystalline counterparts and g‐C₃N₄.     

Porous Organic Frameworks Featured by Distinct Confining Fields for the Selective Hydrogenation of Biomass-Derived Ketones

The asymmetric hydrogenation of biomass-derived molecules for the preparation of single enantiomer compounds is an effective method to reduce the rapid consumption of fossil resources. Porous organic frameworks (POFs) with pure organic surfaces may provide unusual confinement effects for organic substrates in chiral catalysis. Here, a series of POF catalysts are designed with chiral active centers decorated into sharply defined one-dimensional channels with diameters in the range of 1.2–2.9 nm. Due to the synergistic effect originating from the conjugated inner wall, the POF material (aperture size 2.4 nm) concentrates over 90% of aromatic species into the porous architecture, and its affinity is one or two orders of magnitude higher than those of classical porous solids. As determined by PBE+D3 calculation, the phenyl fragment reveals strong π–π interaction for steric hindrance around the metal active site to achieve stronger asymmetric induction. Therefore, this POF catalyst achieves high conversion (>99% yield) and enantioselectivity (>99% ee) for various substrates. The advantages of using the POF platform as a chiral catalyst can provide new perspectives on POF-based solid-state host–guest chemistry and asymmetric heterogeneous catalysis.     

Coordination‐Induced Interlinked Covalent‐ and Metal–Organic‐Framework Hybrids for Enhanced Lithium Storage

Covalent organic frameworks (COF) or metal–organic frameworks have attracted significant attention for various applications due to their intriguing tunable micro/mesopores and composition/functionality control. Herein, a coordination‐induced interlinked hybrid of imine‐based covalent organic frameworks and Mn‐based metal–organic frameworks (COF/Mn‐MOF) based on the Mn? N bond is reported. The effective molecular‐level coordination‐induced compositing of COF and MOF endows the hybrid with unique flower‐like microsphere morphology and superior lithium‐storage performances that originate from activated Mn centers and the aromatic benzene ring. In addition, hollow or core–shell MnS trapped in N and S codoped carbon (MnS@NS‐C‐g and MnS@NS‐C‐l) are also derived from the COF/Mn‐MOF hybrid and they exhibit good lithium‐storage properties. The design strategy of COF–MOF hybrid can shed light on the promising hybridization on porous organic framework composites with molecular‐level structural adjustment, nano/microsized morphology design, and property optimization.     

On the prevention of accidents and injuries : A comparative analysis of conceptual frameworks

The meaning of prevention has changed as new applications of the concept have appeared. Ideas presented in eleven different conceptual frameworks are compared. Identification of the frameworks took place through searches in databases and relevant literature. Five are general by nature, while six relate to injuries and accidents. All are supported by just a few parameters, the time dimension being the most prominent. Compatibility was established on three additional dimensions: level (individual, organizational or societal); direction (“bottom-up” or “top-down”); and in relation to the trichotomy “host-agent-environment”. An attempt to synthesize all these dimensions into one general model of accident and injury prevention is presented.     

Rational Design of Catalytic Centers in Crystalline Frameworks

Crystalline frameworks including primarily metal organic frameworks (MOF) and covalent organic frameworks (COF) have received much attention in the field of heterogeneous catalysts recently. Beyond providing large surface area and spatial confinement, these crystalline frameworks can be designed to either directly act as or influence the catalytic sites at molecular level. This approach offers a unique advantage to gain deeper insights of structure–activity correlations in solid materials, leading to new guiding principles for rational design of advanced solid catalysts for potential important applications related to energy and fine chemical synthesis. In this review, recent key progress achieved in designing MOF‐ and COF‐based molecular solid catalysts and the mechanistic understanding of the catalytic centers and associated reaction pathways are summarized. The state‐of‐the‐art rational design of MOF‐ and COF‐based solid catalysts in this review is grouped into seven different areas: (i) metalated linkers, (ii) metalated moieties anchored on linkers, (iii) organic moieties anchored on linkers, (iv) encapsulated single sites in pores, and (v) metal‐mode‐based active sites in MOFs. Along with this, some attention is paid to theoretical studies about the reaction mechanisms. Finally, technical challenges and possible solutions in applying these catalysts for practical applications are also presented.     

HKUST-1/KCoFC复合材料的制备及其对Cs+的吸附研究

在这项工作中,制备了一种以金属有机配位聚合物(MOFs)材料(HKUST-1)为载体,通过KCoFC(Co(NO₃)₂与K₄Fe(CN)₆反应产物)功能化修饰后的新型复合材料,并通过FTIR、SEM、XRD对其进行表征。研究初始Cs⁺浓度、吸附时间、溶液pH值对吸附效果的影响,用吸附动力学和吸附等温线模型研究HKUST-1/KCoFC对Cs⁺的吸附过程。实验表明:在40 min内,Cs⁺吸附量迅速增加,复合材料对Cs⁺吸附量最佳的pH为8;HKUST-1/KCoFC对Cs⁺吸附过程符合准二级动力学和Langmuir模型。     

Sintering Metal–Organic Framework Gels for Application as Structural Adhesives

Metal–organic frameworks (MOFs)/coordination polymers are promising materials for gas separation, fuel storage, catalysis, and biopharmaceuticals. However, most applied research on MOFs is limited to these functional materials thus far. This study focuses on the potential of MOFs as structural adhesives. A sintering technique is applied to a zeolitic imidazolate framework-67 (ZIF-67) gel that enables the joining of Cu substrates, resulting in a shear strength of over 30 MPa, which is comparable to that of conventional structural adhesives. Additionally, systematic experiments are performed to evaluate the effects of temperature and pressure on adhesion, indicating that the removal of excess 2-methylimidazole and the by-product (acetic acid) from the sintered material by vaporization results in a microstructure composed of large spherical ZIF-67 crystals that are densely aggregated, which is essential for achieving a high shear strength.