- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A New Biscarbazole-Based Metal-Organic Framework for Efficient Host-Guest Energy Transfer
摘要： A new metal–organic framework (MOF), [Zn6L4(Me2NH2+)4·3 H2O] (1) was constructed based on [9,9’-biscarbazole]-3,3’,6,6’-tetracarboxylic acid (H4L) and Zn2+ ions. The porous framework and intense blue fluorescence of the MOF based on the biscarbazole moiety of the ligand could facilitate efficient host to guest energy transfer, which makes it an ideal platform for the tuning of luminescence.
关键词： in situ encapsulation,metal–organic frameworks,energy transfer,host–guest systems,fluorescence
更新于2025-09-23 15:23:52
-
Versatile and Switchable Responsive Properties of a Lanthanide-Viologen Metal-Organic Framework
摘要： Metal–organic frameworks (MOFs) provide intriguing platforms for the design of responsive materials. It is challenging to mobilize as many components as possible of a MOF to collaboratively accomplish multiple responsive properties. Here, reversible photochromism, piezochromism, hydrochromism, ionochromism, and luminescence modulation of an ionic Eu(III) MOF is reported furnished by cationic electron-deficient viologen units and exchangeable guest anions. Mechanistically, the extraordinarily versatile responsive properties are owed to electron transfer (ET), charge transfer (CT), and energy transfer, involving viologen as electron acceptor, anion as electron donor, luminescing Eu(III) as energy donor, and anion-viologen CT complex or ET-generated radical as energy acceptor (luminescence quencher). Moreover, guest anions and waters provide flexible handles to control the ET-based responsive properties. Water release/reuptake or exchange with organic solvents can switch on/off the response to light, while reversible anion exchange can disenable or awaken the responses to pressure, light, and water release/reuptake. The impacts of water and anions on ET are justified by the high polarity and hydrogen-bonding capability of water, the different electron donor strength of anions, and the strong I?-viologen CT interactions. The rich responsive behaviors have great implications for applications such as pressure sensors, iodide detection, and chemical logic gates.
关键词： metal–organic frameworks,electron transfer,charge transfer,luminescence switches,piezochromism
更新于2025-09-23 15:23:52
-
Metal-Organic Frameworks as Hosts for Fluorinated Azobenzenes: A Path Towards Quantitative Photoswitching with Visible Light
摘要： Fifteen new photochromic hybrid materials were synthesized by gas phase loading of fluorinated azobenzenes, namely ortho-tetrafluoroazobenzene (tF-AZB), 4H,4H'-octafluoroazobenzene (oF-AZB), and perfluoroazobenzene (pF-AZB), into the pores of the well-known metal-organic frameworks MOF-5, MIL-53(Al), MIL-53(Ga), MIL-68(Ga), and MIL-68(In). Their composition was analysed by elemental (CHNS) and DSC/TGA analysis. For pF-AZB0.34@MIL-53(Al) a structural model based on high-resolution synchrotron powder diffraction data was developed and the host-guest and guest-guest interactions were elucidated from this model. These interactions of O-H…F and π…π type were confirmed by significant shifts of the O-H frequencies in loaded and unloaded MOFs of the MIL-53 and MIL-68 series. Most remarkably, all of the synthesized F-AZB@MOF systems can be switched with visible light and some of them show almost quantitative (> 95 %) photo-isomerization between its E and Z forms with no significant fatigue after repeated switching cycles.
关键词： azobenzene,fluorinated derivatives,solid state switching,metal-organic frameworks,photochromism
更新于2025-09-23 15:23:52
-
Synthesis, Structure, and Photoluminescence Properties of a Metal-Organic Framework with Hexagonal Channels: Selective Turn-On Sensing for Mg <sup>2+</sup> Ion
摘要： A three-dimensional Cd2+ framework (1) with wide one-dimensional hexagonal channels was prepared based on a tripodal tricarboxylate ligand possessing nitrogen donor atoms. The Cd atoms form a chain structure bridged by carboxylates and aqua ligands. Upon Mg2+ ion capture, the fluorescence emission of this porous material was 5.2 times greater than its Mg2+-free fluorescence. To the best of our knowledge, such enhancement has not been previously reported for metal–organic framework sensory systems. The sensing performance of 1 is reversible over repeated cycles of Mg2+ inclusion and release, revealing the reusability of this material. In the presence of other tested metal ions, Mg2+ ions were selectively detected owing to the operation of this “turn-on” mechanism. Thus, this platform is a promising sensor material for selective Mg2+ ion recognition.
关键词： Sensors,Luminescence,Metal-organic frameworks
更新于2025-09-23 15:23:52
-
A fluorescent Eu(III) MOF for highly selective and sensitive sensing of picric acid
摘要： A metal-organic framework [Eu3L3(CH3COO)2(H2O)2(μ3-OH)]?3DMF, (EuL, H2L=9H-carbazole-2,7-dicarboxylic acid, DMF=N,N-dimethylformamide) has been synthesized under solvothermal conditions and structurally characterized. In EuL, Eu6O8 clusters are four-bridged by carboxylates to form parallel-aligned Eu–O–C chains, which are further linked by the carbazole moieties of L2? ligands to form the three-dimensional framework with rhombic channels. The EuL material with characteristic emission of Eu3+ ion exhibits significant luminescence quenching response for picric acid (PA) and the linear Stern-Volmer plot was observed in the concentration range of 0.05–0.15 mM with Ksv of 98074 M?1. As far as we know, this Ksv is among the highest values for COFs and MOFs in detection of PA. The excellent anti-interference ability and repeatability were also verified by experiments. Lastly, we investigated the luminescence quenching mechanism in the EuL sensing system.
关键词： europium,picric acid,sensor,metal-organic frameworks
更新于2025-09-23 15:23:52
-
Water-Stable Metal–Organic Frameworks with Selective Sensing on Fe <sup>3+</sup> and Nitroaromatic Explosives, and Stimuli-Responsive Luminescence on Lanthanide Encapsulation
摘要： Three water-stable luminescent MOFs [Zn4(bptc)2(NMP)3(DMF)(H2O)2]n (1-a), [Cd4(bptc)2(NMP)3(DMF)2(H2O)1]n (1-b), and {[Zn2(bptc)(DMA)(H2O)2]·(DMA)2·H2O}n (2), possessing similar chemical components (M2:L1:Sol3) and topology structures, were synthesized by solvents control. Their excellent sensing on iron(III) cation and nitroaromatic explosives (NACs) with great selectivity, sensitivity and a high Ksv (4.54 × 10^4 for 1-b on PNP) were observed by quenching effects. Furthermore, Zn-MOFs exhibit interesting stimuli-responsive luminescence enhancement after the encapsulation of a series of IIIB cations stimulated different luminescent emitting and intensity enhancement through host–guest processes of the pores in MOFs, especially for two distinct responses of Zn-MOF on a Tb3+ cation.
关键词： stimuli-responsive,nitroaromatic explosives,luminescent,water-stable,lanthanide encapsulation,iron(III),metal-organic frameworks,sensing
更新于2025-09-23 15:23:52
-
Luminescence properties of a family of lanthanide metal-organic frameworks
摘要： Two isostructural series of lanthanide metal-organic frameworks denoted as SUMOF-7II (Ln) and SUMOF-7IIB (Ln) ( Ln = La, Ce, Pr, Nd, Sm, Eu, and Gd) were synthesized using4,4',4''-(pyridine-2,4,6-triyl)tris(benzoic acid) (H3L2) and a mixture of H3L2 and 4,4′,4′′-(benzene-1,3,5-triyl)tris(benzoic acid) (H3BTB) as linkers, respectively. Both series were characterized usingpowder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal analysis (TGA), and photoluminescence spectroscopy. Photoluminescence measurements show that Eu-MOFs demonstrate a red emission while Pr- and Nd-MOFs display an emission in the near-infrared (NIR) range. On the other hand, La-, Ce-, Sm- and Gd-MOFs exhibit only a ligand-centered emission. The average luminescence lifetimes in the SUMOF-7IIBseries are 1.3-1.4-fold longer than the corresponding ones in the SUMOF-7II series. SUMOF-7IIs show a good photo- and thermal stability. Altogether, the properties of SUMOF-7II and SUMOF-7IIB render them promising materials for applications including sensing, biosensing, and telecommunications.
关键词： Lanthanide MOFs,Antenna Effect,Photostability,Photophysical Properties.,Metal-Organic Frameworks,Luminescence
更新于2025-09-23 15:23:52
-
Efficient and selective sensing of Cu2+ and UO22+ by a europium metal-organic framework
摘要： We report here the investigation of using a luminescent europium organic framework, [Eu2(MTBC)(OH)2(DMF)3(H2O)4]·2DMF·7H2O (denoted as compound 1), for detecting of both Cu2+ and UO2 2+ with high sensitivity. Based on the spectroscopy analysis, compound 1 could selectively respond to Cu2+ and UO2 2+ ions among other selected monovalent, divalent, trivalent metal cations based on a turn-off mechanism. The detection limit of compound 1 towards Cu2+ ion was as low as 17.2 μg/L, which is much lower than the maximum tolerable concentration of Cu2+ in drinking water (2 mg/L) defined by United States Environmental Protection Agency. On the other hand, the detection limit towards UO2 2+ ions is 309.2 μg/L, which could be used for detecting uranium in relative severely contaminated areas. The concentration-dependent luminescence intensity evolution process could be fully understood by the absorption kinetics and isotherm investigations. Furthermore, the quenching mechanism was elucidated by the UV-vis, excitation, luminescence, and lifetime studies. Compound 1, as the first MOF based luminescence probe for both Cu2+ and UO2 2+ ions, provides insight into developing MOF-based multifunctional sensors for both nonradioactive and radioactive elements.
关键词： Adsorption,Copper and uranium contamination,Luminescent metal organic frameworks,Detection
更新于2025-09-23 15:23:52
-
Activated carbon/metal-organic framework nanocomposite: Preparation and photocatalytic dye degradation mathematical modeling from wastewater by least squares support vector machine
摘要： Herein, Kiwi peel activated carbon (AC), Materials Institute Lavoisier (MIL-88B (Fe), and AC/MIL-88B (Fe) composite were synthesized and used as catalysts to degrade Reactive Red 198. The material properties were analyzed by the FTIR, BET-BJH, XRD, FESEM, EDX, TGA, and UV–Vis/DRS. The BET surface area of AC, MIL-88B (Fe) and AC/MIL-88B (Fe) was 1113.3, 150.7, and 199.4 m2/g, respectively. The band gap values (Eg) estimated by Tauc plot method, were obtained 5.06, 4.19 and 3.79 eV for AC, MIL-88B (Fe) and AC/MIL-88B (Fe), respectively. The results indicated that the AC/MIL-88B (Fe) composite had higher photocatalytic activity (99%) than that of pure AC (79%) and MIL-88B (Fe) catalysts (87%). The decolorization kinetic was matched well with the second-order model. Moreover, the data were modeled using least squares support vector machine which optimized with Cuckoo optimization algorithm. The optimal parameters were found 0.837 and 3.49e+02 based on σ2 and γ values, respectively. The mean square error (MSE) and correlation coefficient (R2) values were obtained 3.97 and 0.948. Therefore, the attained data, materials characterization and prediction of modeling validate the composite form of MIL-88B(Fe) with new AC, had better photocatalytic activity in comparison with the individual form.
关键词： Metal-organic frameworks (MOFs),Synthesis,AC/MIL-88B (Fe) composite,COA-LSSVM modeling,Photocatalytic degradation
更新于2025-09-23 15:23:52
-
Mixed-metal organic framework-coated ZnO nanowires array for efficient photoelectrochemical water oxidation
摘要： Designing of high-performance photoanodes is essential for efficient solar energy conversion in photoelectrochemical (PEC) water splitting. Herein, we report an effective approach to synthesize three dimensional (3D) mixed-metal organic framework-coated ZnO nanowires array (ZnNi MOF@ZnO) for the effective PEC performance. The ZnO nanowires act as photon absorber as well as rapid charge transporter; whilst the ZnNi MOF provides the active sites for PEC process by lowering the energy barrier of water oxidation and suppressing electron-hole recombination. The 3D nanostructure of ZnNi MOF@ZnO nanowires array provides intimate interfacial contact through covalent interactions between the ZnNi MOF and ZnO nanowires which facilitates the rapid charge transfer during photocatalytic oxygen evolution reactions. As a result, the ZnNi MOF@ZnO nanowires array exhibited excellent photoelectrochemical water oxidation with very low onset potential (0.31 V vs. RHE) and high photocurrent density (1.40 mA/cm2) as compared to the Zn MOF @ZnO and ZnO nanowires array. This facile strategy provides a promising direction towards high performance photoanode design for adequate solar energy conversion.
关键词： Metal organic frameworks (MOFs),Photoelectrocatalyst,Nanowires array,Photoelectrochemical water oxidation,Photoanodes
更新于2025-09-23 15:22:29