Designing metal-organic frameworks for radiation detection

Five metal-organic frameworks (MOFs) were synthesized and investigated via steady-state photoluminescence and radioluminescence measurements. Unique spectral features were observed in the 2.5 MeV proton spectra, corresponding to differences in the electronic and crystalline structures of each material. Targeted structural transformations and infiltration with extrinsic dopants were also employed to modify the luminescence of these frameworks, establishing MOFs as a platform to design new radiation detection materials.     

多色应力发光的镧系掺杂金属有机框架

金属有机框架(MOF)和应力发光(ML)材料被认为是两种有前途的材料,并在诸多领域得到了广泛应用.若能将二者结合起来获得ML-MOF材料,则势必会拓展它们的应用范围.但目前对MLMOF的研究并不多,且其中的ML机制仍不明确.在本研究中,我们提出了一种通过在非中心对称SBD MOF中掺杂镧系离子来开发ML-MOF的策略,...     

基于金属-有机骨架的锂离子电池硅负极的研究进展

近年来,金属-有机骨架(MOFs)及其衍生物由于具有高孔隙率、可修饰的官能团、可控的化学成分等优点,在改善硅负极体积膨胀和导电性等方面取得了很大进展.通过讨论MOFs及其衍生物在锂离子电池硅负极的最新研究成果,重点阐述了以MOFs为基体的硅负极的结构设计,提出了影响其电化学性能的相关因素.最后,针对MOFs及其衍生物在...     

金属-有机骨架材料水相合成路线研究进展

金属-有机骨架材料具有优异的物理化学性质,因而在气体储存、吸附分离、药物传输、超级电容器、催化等领域具有广阔的应用前景.然而大多数金属-有机骨架材料的合成通常需要用到大量的有机溶剂,而这些有机溶剂的使用不仅会增加金属-有机骨架材料的生产成本,且极易对环境造成影响.基于此,理想的合成路线是用水代替有害的有机溶剂,以降低成本及减轻其对环境的影响.本文总结了近期金属-有机骨架材料水相合成路线的研究进展,重点概括了不同水相合成法制备金属-有机骨架材料的机理,并分析了各种方法的优缺点.此外,还讨论了当前绿色且低成本工业化生产金属-有机骨架材料存在的问题以及未来可能的发展方向.     

Functionalization of silicon nanowire surfaces with metal-organic frameworks

Metal-organic frameworks (MOFs) and silicon nanowires (SiNWs) have been extensively studied due to their unique properties; MOFs have high porosity and specific surface area with well-defined nanoporous structure, while SiNWs have valuable one-dimensional electronic properties. Integration of the two materials into one composite could synergistically combine the advantages of both materials and lead to new applications. We report the first example of a MOF synthesized on surface-modified SiNWs. The synthesis of polycrystalline MOF-199 (also known as HKUST-1) on SiNWs was performed at room temperature using a step-by-step (SBS) approach, and X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy elemental mapping were used to characterize the material. Matching of the SiNW surface functional groups with the MOF organic linker coordinating groups was found to be critical for the growth. Additionally, the MOF morphology can by tuned by changing the soaking time, synthesis temperature and precursor solution concentration. This SiNW/MOF hybrid structure opens new avenues for rational design of materials with novel functionalities.      

Spatial compartmentalization of metal nanoparticles within metal-organic frameworks for tandem reaction

Fabrication of multifunctional catalysts has always been the pursuit of synthetic chemists due to their efficiency,cost-effectiveness,and environmental friendliness.However,it is difficult to control multi-step reactions in one-pot,especially the spatial compartmentalization of incompatible active sites.Herein,we constructed metal-organic framework(MOF)composites which regulate the location distribution of metal nanoparticles according to the reaction path and coupled with the diffusion of substrates to achieve tandem reaction.The designed UiO-66-Pt-Au catalyst showed good activity and selectivity in hydrosilylation-hydrogenation tandem reaction,because the uniform microporous structures can control the diffusion path of reactants and intermediates,and Pt and Au nanoparticles were arranged in core-shell spatial distribution in UiO-66.By contrast,the low selectivity of catalysts with random deposition and physical mixture demonstrated the significance of artificial control to the spatial compartmentalization of active sites in tandem catalytic reactions,which provides a powerful approach for designing high-performance and multifunctional heterogeneous catalysts.     

Spatial compartmentalization of metal nanoparticles within metal-organic frameworks for tandem reaction

Fabrication of multifunctional catalysts has always been the pursuit of synthetic chemists due to their efficiency,cost-effectiveness,and environmental friendliness.However,it is difficult to control multi-step reactions in one-pot,especially the spatial compartmentalization of incompatible active sites.Herein,we constructed metal-organic framework(MOF)composites which regulate the location distribution of metal nanoparticles according to the reaction path and coupled with the diffusion of substrates to achieve tandem reaction.The designed UiO-66-Pt-Au catalyst showed good activity and selectivity in hydrosilylation-hydrogenation tandem reaction,because the uniform microporous structures can control the diffusion path of reactants and intermediates,and Pt and Au nanoparticles were arranged in core-shell spatial distribution in UiO-66.By contrast,the low selectivity of catalysts with random deposition and physical mixture demonstrated the significance of artificial control to the spatial compartmentalization of active sites in tandem catalytic reactions,which provides a powerful approach for designing high-performance and multifunctional heterogeneous catalysts.     

Highly luminescent metal-organic frameworks through quantum dot doping

The incorporation of highly luminescent core-shell quantum dots (QDs) within a metal-organic framework (MOF) is achieved through a one-pot method. Through appropriate surface functionalization, the QDs are solubilized within MOF-5 growth media. This permits the incorporation of the QDs within the evolving framework during the reaction. The resulting QD@MOF-5 composites are characterized using X-ray fluorescence, cross-sectional confocal microscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and small-angle X-ray scattering. The synergistic combination of luminescent QDs and the controlled porosity of MOF-5 in the QD@MOF-5 composites is harnessed within a prototype molecular sensor that can discriminate on the basis of molecular size.     

Photothermy-strengthened photocatalytic activity of polydopamine-modified metal-organic frameworks for rapid therapy of bacteria-infected wounds

Herein,a metal-organic framework(MOF)was modified using polydopamine(PDA)to develop the MOFPDA as a photoresponsive bacteria-killing agent under 660 nm light irradiation.The modification using PDA led to the production of not only more heat,but also much more~1O₂.This is because the PDA could interact with the porphyrin ring of the MOF throughπ-πinteraction and the charge transfer between PDA and the MOFs decreases the ene rgy of the band of hybrid nanoparticles.In addition,greater levels of hyperthermia induced by PDA modification accelerated the charge trans fe r,which significantly strengthened the photocatalytic perfo rmance of MO F-PDA.Furthermore,after modification,the light abso rbance and water dispersibility of nanoparticles were both enhanced;both are important for the improvement of photocatalytic and photothermal properties.Consequently,MOF-PDA exhibited the highly effective antibacterial efficacy of 99.62%and 99.97%against Staphylococcus aureus and Escherichia coli,respectively,under 20 min 660 nm light irradiation.     

Chiral nanoporous metal-organic frameworks with high porosity as materials for drug delivery

A chiral nanoporous metal-organic framework (MOF) with high porosity is obtained based on nontoxic zinc and achiral hexadentate ligand. It shows high drug loading and slow release of the proportion of the loaded drug with a complete delivery time of about one week when used as a material for adsorption and delivery of anticancer 5-fluorouracil.     

镧系金属有机骨架/聚酰亚胺复合材料的制备及其性能

采用水热法合成两种含镧系稀土金属的金属有机骨架：1,3,5-均苯三甲酸铽（Tb （BTC））和1,3,5-均苯三甲酸铕（Eu （BTC））,采用原位法以1,4-双（2-三氟甲基-4-氨基苯氧基）苯（6FAPB）和1,2,3,4-环丁烷四酸二酐（CBDA）为单体,将Tb （BTC）和Eu （BTC）分别引入到聚酰亚胺（PI）中,制备出Tb （BTC）和Eu （BTC）质量分数分别为7wt%的Tb （BTC）/PI和Eu （BTC）/PI两种复合材料膜。利用FTIR、紫外-可见光谱仪（UV-vis）、TGA、XRD、SEM、万能拉伸试验机和气体渗透性测试等对Tb （BTC）/PI和Eu （BTC）/PI复合材料的结构和性能进行表征。研究结果表明,Tb （BTC）和Eu （BTC）含有较少的孔结构,且孔径在介孔范围,但热稳定性较高。Tb （BTC）和Eu （BTC）的加入提高了Tb （BTC）/PI和Eu （BTC）/PI复合材料的热性能和力学性能,玻璃化转变温度由纯PI （6FAPB-CBDA）的351.9℃分别提高到358.0℃和354.8℃,失重5%热分解温度由431.6℃分别提高到447.8℃和441.1℃,拉伸强度由60.8 MPa分别提高到77.7 MPa和70.4 MPa,杨氏模量由1.54 GPa分别提高到2.80 GPa和2.17 GPa。但Tb （BTC）/PI和Eu （BTC）/PI复合材料膜的光透明性有所降低,500 nm处的光透过率由82.3%分别下降到23.0%和24.2%。气体渗透测试结果表明,Tb （BTC）和Eu （BTC）的加入均可提高PI （6FAPB-CBDA）膜的气体渗透性,Eu （TBC）/PI对H₂、O₂、N₂和CO₂的渗透性较高,分别为119.23、15.02、3.21和90.35 Barrer,O₂/N₂为4.68,CO₂/N₂为28.15。     

High photoluminescent metal-organic frameworks as optical markers for the identification of gunshot residues

Gunshot residue (GSR) are solid particles produced when a firearm is discharged, and its detection is important evidence in forensic investigations. Currently, scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS) is the standard technique adopted for the analysis and identification of GSR; however, this methodology is inefficient for lead-free ammunition. Herein, we report the inclusion of high photoluminescent metal-organic frameworks in ammunition to allow for the visual detection of GSR. The tests indicated that marked GSR is easily visible in proportions above 5.0 wt %. A total of 1 g of marker suffices to tag 100 0.38 mm bullets or 62 0.40 mm bullets.     

Photochemical hydrogen production from water using three-dimensional Zn-Pd metal-organic frameworks

A Zn-Pd heterometallic metal-organic framework (MOF) based on 3,5-pyridine-dicarboxylic acid (H2-pydc), namely [Zn2(H2O)3{PdCl2(pydc)2}]n (Zn-Pd-2) was successfully synthesized by a slow diffusion method and characterized by single-crystal X-ray diffraction, CHN elemental analysis, FT-IR spectroscopy, thermogravimetric (TG) analysis and N2 gas adsorption measurement. The single-crystal X-ray analysis revealed that the framework morphology of Zn-Pd-2 is as same as that of [Zn2(DMF)3{PtCl2(pydc)2}]n. The Zn-Pd-2 was found to be an effective catalytic performance for the photochemical reduction of water in a well-known photo-system made up of [Ru(bpy)3Cl2] (bpy = 2,2'-bipyridine), MV(2+) (methyl-viologen) and Na2 EDTA (Disodium ethylenediaminetetraacetate); 20.2 turnover based on Zn-Pd-2 was achieved at 4 h irradiation.     

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.     

Controlled self-assembly of metal-organic frameworks on metal nanoparticles for efficient synthesis of hybrid nanostructures

We report a novel approach for synthesizing inorganic nanoparticle/metal-organic frameworks (MOFs) heterostructured nanocomposites by self-assembly of MOFs on nanoparticles. This approach involves the synthesis of Au nanoparticles and preferential growth of [Cu(3)(btc)(2)](n) frameworks consisting of Cu(2+) ions and benzene-1,3,5-tricarboxylate (btc) on nanoparticles. Aggregates consisting of 11-mercaptoundecanoic acid (MUA)-stabilized Au nanoparticles linked by Cu(2+) ions were necessary for preferential self-assembly of [Cu(3)(btc)(2)](n) frameworks on the aggregates, resulting in the formation of Au nanoparticles/[Cu(3)(btc)(2)](n) nanocomposites. The present approach was confirmed to be applicable for other hybrids consisting of Au nanoparticles and tetragonal [Cu(2)(ndc)(2)(dabco)](n) frameworks.     

Solvothermal synthesis of La-based metal-organic frameworks and their color-tunable photoluminescence properties

A series of La-based metal?organic frameworks (La-MOFs) phosphors have been successfully synthesized by a facile solvothermal method without assistance of any surfactant or template. The results show that the ethanol volume ratio is important to obtain adjustable shape and size of La-MOFs in the synthesis process. The obtained samples possess flake-like architectures with about 3–5 μm in length. Under UV excitation, all the La-MOFs:Tb³⁺, Eu³⁺ phosphors exhibit the characteristic emissions of Tb³⁺ and Eu³⁺. Moreover, the emitting color of the as-obtained products can be acquired from green, green-yellow, yellow, yellow-orange, orange, to red owing to the efficient energy transfer (ET) between Tb³⁺ and Eu³⁺ions. The ET efficiency of the samples was calculated, and the maximum was found about 96.84%. Furthermore, the dipole–quadrupole interaction has been reasonable proved by the energy transfer between Tb³⁺ and Eu³⁺. These results indicated that La-MOFs:Tb³⁺, Eu³⁺ might be as a novel potential candidate as phosphors for displays and lightings.

     

Combining metal-organic frameworks(MOFs)and covalent-organic frameworks(COFs):Emerging opportunities for new materials and applications

In the past decades,metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)basically enjoy the coordination chemistry and covalent chemistry,respect...