两性离子双功能化超亲水金属有机框架纳米复合材料的制备及其用于糖肽的选择性富集

蛋白糖基化是生物体中普遍发生且重要的生物学过程,其参与多种分子生物学的功能和途径,是临床诊断重要的生物标志物.但是,糖肽因其丰度低、离子化效率低、糖链异质性等难点,使糖蛋白分析一直面临巨大的挑战.因此,研究合成了一种新型的两性离子双功能化纳米金(AuGC)修饰的超亲水性沸石咪唑骨架(ZIF-8)纳米复合材料(AuGC/...     

A composite metal-organic framework material with high selective adsorption for dibenzothiophene

A composite metal-organic framework material Ag⁺/MOF-101 was synthesized and applied to adsorb dibenzothiophene (DBT) from model oils. The loading of Ag⁺ enhanced the deep adsorptive desulfurization capacity for DBT and significantly weaken the adsorption competitiveness of toluene.     

A pillar-layered Cd(II) metal-organic framework for selective detection of organic explosives

The detection of explosives is crucial for homeland security, environmental cleaning, and military issues. As a new class of porous materials, metal-organic frameworks (MOFs) are promising platforms for the detection of organic explosives. In this work, a new pillar-layered Cd(II) MOF, [CdL_0.5dpe_0.5]·2H₂O (BUT-202, H₄L = 4,8-disulfonaphthalene-2,6-dicarboxylic acid, dpe = 1,2-bis(4-pyridyl)ethylene), was synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, and elemental analysis. BUT-202 has good fluorescent properties, which can be selectively quenched by trace amounts of 2,4,6-trinitrophenol (TNP) in DMF with low detection limit of 0.2 μM.     

A new Dy(III)-based metal-organic framework with polar pores for pH-controlled anticancer drug delivery and inhibiting human osteosarcoma cells

Anticancer drug delivery is considered as the most common and patient acceptable drug administration with reduced side effects. In general, an ideal drug carrier for anticancer drug delivery should have high drug loading capacity, good biocompatibility, and avoid drug delivery in normal tissue (neutral conditions) and promoting the drug release in cancerous tissue (acidic condition). Herein, we synthesize a new porous Dy(III)-based metal-organic framework, [Dy(HABA)(ABA)](DMA)₄] (1, H₂ABA = 4,4'-azanediyldibenzoic acid, DMA = N,N-dimethylacetamide) with uncoordinated N donor sites in the porous surroundings using a bent polycarboxylic acid linker under solvothermal conditions. The structure of the obtained crystalline product has been determined by X-ray single-crystal diffraction, elemental analysis, TGA, XRD, and gas sorption measurement. Due to the suitable window size and polar atom functionalized 1D channels, the activated 1 (1a) was used for anticancer drug 5-Fu loading. A moderately high drug loading and pH-dependent drug-release behavior could be observed for 1a. Furthermore, as demonstrated by the MTT assay, this drug/MOF composite shows low cytotoxicity, good biocompatibility, and anticancer activity against human osteosarcoma cell lines MG63.     

Novel Metal-organic Framework Compound Pb（C5H4NCOO）2 Showing One-dimensional Channel Defined as Four Leads and Four Nicotinic Acids

A novel metal-organic framework(MOF) compound of Pb(C5H4NCOO)2 was hydrothermally synthesized and structurally determined by X-ray single-crystal diffraction. The data of unit cell:orthorhombic space group Pccn,a=1.0325(2) nm,b=1.3597(3) nm,c=0.8499(2) nm,V=1.1931(4) nm3,Z=4,Dc=2.513 g/cm3,R1=0.047 were obtained on the basis of 1365 reflections with Fo>2σ(Fo). PbN2O6 polyhedron adopts the distorted cubic configuration which is assigned to the holodirected geometry. These PbN2O6 polyhedra can form the zigzag...     

A cationic metal-organic framework based on {Zn4} cluster for rapid and selective adsorption of dyes

A unique cluster-based cationic framework was successfully constructed by a mixed-ligand strategy. Due to the cationic network and guest anionic molecules in 1D open channels, the MOF can rapidly and selectively adsorb anionic dyes in ethanol solution and release dyes easily based on chargeexclusive effect.     

A new 3D nickel(II) framework composed of large rings: Ionothermal synthesis and crystal structure

Ionothermal reaction between Ni²⁺ and 1,3,5-benzentricarboxylic acid (H₃BTC) with [AMI]Cl (AMI=1-amyl-3-methylimidazolium) as the reaction medium produced a novel 3D mixed-ligand metal-organic framework [AMI][Ni₃(BTC)₂(OAc)(MI)₃] (1) (MI=1-methylimidazole) with [AMI]⁺ incorporated in the framework. The framework is formed by connecting 2D planes, made up of 32- and 48-membered rings, through 1D chains composed of 32-membered rings. The two BTC³⁻ ligands in 1 show the same connectivity mode with two bidentate and one μ₂ bridging carboxylic groups. This is a new connectivity mode to the already existing 17 in the Ni-BTC system. The role of MI and [AMI]Cl in the structure formation is discussed.     

MOF负载[Ru(bpy)3]2+促进CO2还原反应中贵金属光敏剂的分离和循环利用

在太阳光驱动下,将温室气体CO2还原为燃料分子有望解决人类社会面临的环境污染和能源危机问题.此外,CO通常被用作C1源进行精细化学品制备.因此,开发高活性光催化体系将CO2高选择性还原到CO具有重要科学和实用意义.光催化体系主要由光敏剂、催化剂和电子给体构成,其中光敏剂作为光吸收中心和电子转移桥梁在光催化进程中扮演着极其重要的角色.半个多世纪以来,贵金属配合物光敏剂(如[Ru(bpy)3]2+)因其良好的可见光吸收能力和适中的氧化还原能力,被广泛用于光催化CO2还原体系中.然而,贵金属配合物存在光化学稳定性较差、难以回收利用等问题,严重限制了其广泛应用.因此,开发高效、稳定且易于循环利用的贵金属光敏剂用于CO2光还原具有重要意义.本文采用溶剂热合成法,成功将[Ru(bpy)3]2+限域到金属有机框架中,通过调控钌配体的引入比例制得了一系列非均相钌基光敏剂(UiO-Ru-1,UiO-Ru-2和UiO-Ru-3).通过X射线衍射、高分辨场发射扫描电镜和高分辨场发射透射电镜等技术证明了UiO-Ru的结构和形貌(正八面体).将UiO-Ru用于光催化CO2还原,以四联吡啶铁作为催化剂,UiO-Ru-2表现出极高的敏化能力,在300W氙灯下反应8h,CO的产率可达171mmol/g,同时选择性达到100％,是目前活性较高的光催化CO2还原体系之一.该体系中,UiO-Ru-2循环利用三次,其催化效率没有明显衰减,表明其具有良好的光催化稳定性和可循环利用性.值得注意的是,钌含量增加(UiO-Ru-3)或者降低(UiO-Ru-1)催化活性均有所下降.为解释这一现象,本文利用稳态/瞬态光谱和电化学等技术手段对材料的光电化学性质进行了系统的研究.稳态光谱测试结果表明,随着Ru含量的增加,UiO-Ru的吸光和发光性能逐渐提升,但激发态寿命却在逐渐降低.此外,Ru含量增加会占据孔道,减小金属有机框架的孔径,阻碍底物和活性中心的接触.因此,UiO-Ru-2中钌光敏中心含量适中,较好地平衡了可见光吸收能力、激发态寿命和孔道大小之间的关系,使得其催化活性显著优于其它光敏剂(UiO-Ru-1和UiO-Ru-3).此外,本文利用瞬态吸收光谱和电化学深入研究了光催化机制和电子转移路径,将为高活性贵金属光敏剂异相化并用于构建高效、可持续的CO2还原体系提供重要借鉴.     

An anionic In(III)-based metal-organic framework with Lewis basic sites for the selective adsorption and separation of organic cationic dyes

An In(Ⅲ)-based metal-organic framework (BUT-29) can selectively absorb cationic dyes in DMF even in the presence of other organic dyes, and has the higher adsorption capacity.     

Selective CO(2) adsorption in a metal-organic framework constructed from an organic ligand with flexible joints

A metal-organic framework (SNU-110) constructed from an organic ligand with flexible joints exhibits selective CO(2) adsorption over N(2), O(2), H(2) and CH(4) gases.     

A 3-D metal-organic framework constructed with cobalt(II), 1,3-di(4-pyridyl)propane (bpp) and 3,5-dinitrobenzoate (DNBA) with methyl-3,5-dinitrobenzoate (MDNBA) by in-situ synthesis as a guest

A new 3-D cobalt(II) mixed ligand, metal-organic framework {[Co₂(bpp)₂(DNBA)₄H₂O] ·?MDNBA} (1), (bpp =?1,3-di(4-pyridyl)propane, DNBA =?3,5-dinitrobenzoate and MDNBA =?methyl-3,5-dinitrobenzoate) was synthesized in aqueous-methanol medium. X-ray structural analysis of 1 revealed that the dinuclear cobalt clusters interlinked by two μ-carboxylates and a μ ₂ water molecule, acting as a node, are connected to four other clusters through bridging bpp to generate an extended neutral 3-D network. MDNBA was in-situ synthesized and encapsulated in the framework as a guest molecule. Moreover, the fluorescence spectrum shows 1 exhibits blue fluorescent emission in the solid state at room temperature.     

Effect of the guest solvent molecules on preparation of different morphologies of ZnO nanomaterials from the [Zn2(1,4-bdc)2(dabco)] metal-organic framework

The host and the apohost framework of [Zn₂(1,4-bdc)₂(dabco)]?·?4DMF?·?½H₂O (1?·?4DMF?·?½H₂O) (1,4-bdc?=?1,4-benzenedicarboxylate and dabco?=?1,4-diazabicyclo[2.2.2]octane) were used for the preparation of ZnO nanomaterials. With calcination of the host framework of 1?·?4DMF?·?½H₂O, ZnO nanoparticles could be fabricated. By the same process on fully desolvated framework of 1, ZnO microrods composed of ZnO nanoparticles were formed. These results indicate with removal of the guest solvent from the pores of this metal-organic framework (MOF), nanoparticle agglomeration increases and the role of this MOF in preparation of ZnO nanoparticles was reduced.     

Construction of metal-organic frameworks through coordination and hydrogen bonding interactions: Syntheses, structures and photoluminescent properties of metal complexes with macrocyclic ligand

A macrocyclic ligand L with two diethylenetriamine units linked by two rigid biphenylene spacers was used as building block for construction of metal-organic frameworks. A silver(I) complex with macrocyclic and open-chain mix-type ligands [Ag₂(L)(L′)](ClO₄)₂ (1) [L′=1,6-bis(4-imidazol-1′-ylmethylphenyl)-2,5-diazahexane] was obtained by reaction of L and L′ together with AgClO₄·H₂O. It is interesting that the open-chain tetradentate ligand L′ only served as a bidentate ligand to bridge the Ag₂L units into an infinite one-dimensional (1D) cationic chain. Neutral 1D chain coordination polymer [Cu₂(L)(μ-SO₄)₂]·3H₂O·3MeOH (2) is formed by sulfate bridges between the neighboring Cu₂L units. When L reacted with nickel(II) sulfate instead of copper(II) sulfate, a monomacrocycle molecular complex [Ni₂(L)(H₂O)₄(SO₄)₂] (3) was obtained in which the sulfate anion acts as monodentate ligands rather than as bridges. When Cd(II) salts were used for the reactions with L, another two neutral 1D coordination polymers, [Cd₂(L)(μ-Cl)₂Cl₂]·2H₂O (4) and [Cd₂(L)(μ-Br)₂Br₂] (5), with the same structure were isolated. All the synthesized complexes exhibit three-dimensional framework structures linked by various hydrogen bonds. The photoluminescent properties of the synthesized complexes were studied in the solid state at room temperature, and the Ag(I) and Cd(II) complexes were found to show strong blue luminescence.     

A metal-organic framework with highly polar pore surfaces: selective CO2 adsorption and guest-dependent on/off emission properties

A 3D porous Zn(II) metal-organic framework {[Zn(2)(H(2)dht)(dht)(0.5)(azpy)(0.5)(H(2)O)]·4H(2)O} (1; H(2)dht=dihydroxyterphthalate, azpy=4,4'-azobipyridine) has been synthesised by employing 2,5-dihydroxyterephthalic acid (H(4)dht), a multidentate ligand and 4,4'-azobipyridine by solvent-diffusion techniques at room temperature. The as-synthesised framework furnishes two different types of channels: one calyx-shaped along the [001] direction and another rectangle-shaped along the [101] direction occupied by guest water molecules. The dehydrated framework, {[Zn(2)(H(2)dht)(dht)(0.5)(azpy)(0.5)]} (1') provides 52.7% void volume to the total unit-cell volume. The pore surfaces of 1' are decorated with unsaturated Zn(II) sites and pendant hydroxyl groups of H(2)dht linker, thereby resulting in a highly polar pore surface. The dehydrated framework 1' shows highly selective adsorption of CO(2) over other gases, such as N(2), H(2), O(2) and Ar, at 195 K. Photoluminescence studies revealed that compound 1 exhibits green emission (λ(max)≈530 nm) on the basis of the excited-state intramolecular proton-transfer (ESIPT) process of the H(2)dht linker; no emission was observed in dehydrated solid 1'. Such guest-induced on/off emission has been correlated to the structural transformation and concomitant breaking and reforming of the OH···OCO hydrogen-bonding interaction in the H(2)dht linker in 1'/1.     

基于金属有机框架水凝胶的一步式快速富集检测养殖水体中孔雀石绿北大核心CSCD

孔雀石绿是一种三苯甲烷类化合物,在水产品饲养中对疾病的防治有着不错的疗效,但因对人体健康有危害而被列为禁用药。由于实际样品中成分复杂,对于此类染料的检测方法难以同时兼具富集性好、灵敏度高且方便快速的优点。该工作制备了金属有机框架材料(MOF),采用MOF纳米材料掺杂的水凝胶(PAAM-SA/MOF)对养殖水体中的孔雀石绿进行吸附研究。采用一系列表征手段对MOF、PAAM-SA和PAAM-SA/MOF的微观形貌进行分析,结果表明吸附材料已成功合成。通过优化水凝胶吸附剂用量、吸附时间、孔雀石绿溶液pH、吸附温度、孔雀石绿溶液初始浓度等吸附萃取条件,使溶液中的孔雀石绿基本完全吸附在水凝胶中,在最优条件下,吸附效率最高可达97%。此外,采用不同极性的有机溶剂对吸附的孔雀石绿进行洗脱,通过优化洗脱液体积,脱附率最高达99%。在最佳条件下,该方法在高、中、低3个水平下的样品加标回收试验中回收率达到84.8%~118.1%,相对标准偏差小于5.1%,方法的检出限为0.083μg/L(S/N=3),定量限为0.25μg/L(S/N=10)。该方法简化了前处理过程,结合了MOF和水凝胶这二者各自的优点,添加的MOF材料可以在水凝胶体系中发挥其良好的吸附性,既解决了传统的MOF材料因粒径太小而回收率低的难题,便于吸附后直接提取,同时也解决了纯水凝胶吸附效率较低的问题,整体上提高了吸附效率和可回收性。实际样品测试表明该新型水凝胶吸附材料可用于养殖水体中孔雀石绿的快速萃取和检测,在食品检测领域具有很大潜力。     

Mn(II)-based porous metal-organic framework showing metamagnetic properties and high hydrogen adsorption at low pressure

A Mn(II)-based homometallic porous metal-organic framework, Mn(5)(btac)(4)(μ(3)-OH)(2)(EtOH)(2)·DMF·3EtOH·3H(2)O (1, btac = benzotriazole-5-carboxylate), has been solvothermally synthesized and structurally characterized by elemental analysis, thermogravimetric analysis, and X-ray crystallographic study. 1 is a 3D neutral framework featuring 1D porous channels constructed by {Mn-OH-Mn}(n) chains and btac linkers. Magnetic studies show that 1 is a 3D metamagnet containing 1D {Mn-OH-Mn}(n) ferrimagnetic chains. High-pressure H(2) adsorption measurement at 77 K reveals that activated 1 can absorb 0.99 wt % H(2) at 0.5 atm and reaches a maximum of 1.03 wt % at 5.5 atm. The steep H(2) absorption at lower pressure (98.2% of the storage capacity at 0.5 atm) is higher than the corresponding values of some MOFs (MIL-100 (16.1%), MOF-177 (57.1%), and MOF-5 (22.2%)). Furthermore, activated 1 can adsorb CO(2) at room temperature and 275 K. The adsorption enthalpy is 22.0 kJ mol(-1), which reveals the high binding ability for CO(2). Detailed gas sorption implies that the exposed Mn(II) coordination sites in the activated 1 play an important role to improve its adsorption capacities.     

Construction of three new metal-organic frameworks with distinct SBUs: trinuclear {Cd3(COO)6} clusters,inorganic -Cd-O-Cd- chains,and heterometallic trinuclear {Cd2Ba(COO)4} clusters

Three metal-organic frameworks (MOFs), [Cd₃(OABDC)₂(e-urea)₄]_n (1), [Cd₃(OABDC)₂(H₂O)₅)]_n (2) and [Cd₂Ba(OABDC)₂(H₂O)₇]_n (3) (H₃OABDC = 5-oxyacetate isophthalic acid, e-urea = 2-imidazolidinone), were prepared using H₃OABDC and metal salts. Single-crystal X-ray diffraction analyses reveal that 1 features a 2-D layered structure constructed from trinuclear {Cd₃(COO)₆} SBUs and represents a (3,6)-connected kgd topology. Compounds 2 and 3 are 3-D inorganic–organic hybrid frameworks; 2 employs infinite inorganic –Cd–O–Cd– chains as SBUs, whereas (3,6)-connected ant-type 3 employs heterometallic trinuclear {Cd₂Ba(COO)₄} clusters as SBUs. The structures of these three compounds indicate that the SBUs play an important role in the construction of MOFs. Moreover, the thermal stabilities and solid-state photoluminescent properties of these three compounds have also been investigated.     

A zinc(II) metal-organic framework based on triazole and dicarboxylate ligands for selective adsorption of hexane isomers

A three-dimensional (3D) metal-organic framework {[Zn(2)(HBDC)(2)(dmtrz)(2)]·guest}(n) with pcu net has been solvothermally synthesized, which shows selective adsorption of linear and monobranched hexane isomers over a dibranched one.     

Preparation and characterization of metal-organic framework MIL-101(Cr)-coated solid-phase microextraction fiber

Metal-organic frameworks (MOFs) have received great attention as novel sorbents due to their fascinating structures and intriguing potential applications in various fields. In this work, a MIL-101(Cr)-coated solid-phase microextraction (SPME) fiber was fabricated by a simple direct coating method and applied to the determination of volatile compounds (BTEX, benzene, toluene, ethylbenzene, m-xylene and o-xylene) and semi-volatile compounds (PAHs, polycyclic aromatic hydrocarbons) from water samples. The extraction and desorption conditions of headspace SPME (HS-SPME) were optimized. Under the optimized conditions, the established methods exhibited excellent extraction performance. Good precision (<7.7%) and low detection limits (0.32–1.7 ng L⁻¹ and 0.12–2.1 ng L⁻¹ for BTEX and PAHs, respectively) were achieved. In addition, the MIL-101(Cr)-coated fiber possessed good thermal stability, and the fiber can be reused over 150 times. The fiber was successfully applied to the analysis of BTEX and PAHs in river water by coupling with gas chromatography–mass spectrometry (GC–MS). The analytes at low concentrations (1.7 and 10 ng L⁻¹) were detected, and the recoveries obtained with the spiked river water samples were in the range of 80.0–113% and 84.8–106% for BTEX and PAHs, respectively, which demonstrated the applicability of the self-made fiber.