Dual-function Metal-organic Framework Research Articles

A homogeneous capillary fluorescence imprinted nanozyme intelligent sensing platform for high sensitivity and visual detection of triclocarban

A homogeneous capillary fluorescence imprinted nanozyme intelligent sensor based on a dual-function metal-organic framework (NH2-MIL-101(Fe)) has been developed for highly sensitive and visual determination of triclocarban (TCC). The NH2-MIL-101(Fe) exhibited peroxidase-like properties to oxidize o-phenylenediamine to 2,3-diaminophenazine with yellow fluorescence (570 nm), which in turn suppresses the intrinsic fluorescence peak (445 nm) owing to the inner filter effect. The capillary fluorescence detection system was constructed by inhaling molecularly imprinted polymers solution with H2O2 and o-phenylenediamine into the capillary, which realized the homogeneous distribution of molecularly imprinted polymers in the capillary without the tedious operation of coating the inner wall of the capillary. TCC restored the fluorescence at 445 nm while quenching the fluorescence at 570 nm, resulting in a color shift from yellow to green to blue. The linear range of the fluorescence capillary imprinted sensor was determined to be 10 pM- 3.5 nM with the detection limit of 8.5 pM. The fluorescence color was converted to RGB value by using the smartphone to calculate TCC concentration with the detection limit of 9.8 pM, which provided a novel method for the determination of environmental pollutants with the microvolume consumption (18 μL/time).

Two Stable Cd-MOFs as Dual-Functional Materials with Luminescent Sensing of Antibiotics and Proton Conduction.

Construction and investigation of dual-functional metal-organic frameworks (MOFs) with luminescent sensing and proton conduction provide widespread applications in clean energy and environmental monitoring fields. By selecting a phosphonic acid ligand 4-pyridyl-CH2N(CH2PO3H2)2 (H4L) and coligand 2,2'-biimidazole (H2biim), two cadmium-based MOFs [Cd1.5(HL)(H2biim)0.5] (1) and (H4biim)0.5·[Cd2(L)(H2biim)Cl] (2) with different structures and properties have been hydrothermally synthesized by controlling reaction temperature. Based on the excellent thermal and chemical stabilities, and good luminescent stabilities in water solution, 1 and 2 can serve as luminescent sensors of chloramphenicol (CAP) with different quenching constant (KSV) values and detection limits (LODs) in water, simulated environmental system, and real fish water system. Meanwhile, different sensing effects and possible sensing mechanisms are analyzed in detail. Moreover, 1 and 2 can also serve as good proton-conducting materials. The proton conductivities can reach up to 1.41 × 10-4 S cm-1 for 1 and 1.02 × 10-3 S cm-1 for 2 at 368 K and 95% relative humidity (RH). Among them, 2 shows better luminescent sensing and proton conduction performance than 1, which indicates that different crystal structures have a great impact on the properties of MOFs. Through the discussion of the relationship between structures and properties in detail, the possible reasons for the differences in properties are obtained, which can provide theoretical guidance for the rational design of this kind of dual-functional MOFs in the future.

Designing Dual-Functional Metal–Organic Frameworks for Photocatalysis

Designing Dual-Functional Metal–Organic Frameworks for Photocatalysis

Isomeric sp2-C-conjugated porous organic polymer-mediated photo- and sono-catalytic detoxification of sulfur mustard simulant under ambient conditions

Isomeric sp2-C-conjugated porous organic polymer-mediated photo- and sono-catalytic detoxification of sulfur mustard simulant under ambient conditions

Dual-Functional Metal-Organic Framework for Luminescent Detection of Carcinoid Biomarkers and High Proton Conduction.

It remains a challenge to exploit dual-functional metal-organic frameworks (MOFs) for applications, including luminescence detection and proton conduction. With the deliberate selection of the bifunctional organic ligand 5-sulfoisophthalic acid monosodium salt (NaH2bts), and the phosphonic acid ligand N,N'-piperazine (bismethylenephosphonic acid; H4L), a robust three-dimensional (3D) noninterpenetrating dual-functional MOF, [Tb(H2L)(H2bts)(H2O)]·H2O (1), has been synthesized hydrothermally. On the basis of the excellent thermal and chemical as well as superior luminescence stabilities in water and solutions with different pHs, 1 can serve as the simple, rapid, and highly selective and sensitive luminescence detection of the carcinoid biomarkers 5-hydroxytryptamine (HT) and its metabolite 5-hydroxyindole-3-acetic acid (HIAA) with detection limits of nanomolar magnitude in water and in simulated blood plasma and urine systems. Due to the change in the signals that could be readily differentiated by the naked eye under a UV lamp, a portable test paper has been developed. The probable quenching mechanisms are discussed in detail. In addition, a great number of hydrogen-bonding networks are formed among the uncoordinated carboxylic oxygen atoms, sulfonate oxygen atoms, protonated nitrogen atoms, and water molecules, which provide potential proton-hopping sites for proton conduction, leading to a maximum proton conductivity of 2.3 × 10-4 S cm-1 at 368 K and 95% relative humidity. The above results suggest that rationally designed dual-functional MOFs can open an avenue for the development of occupational diagnostic tools and alternative energy technology.

Dual-Function Metal–Organic Framework as Efficient Turn-Off Sensor for Water and Unusual Turn-On Sensor for Ag+

Fluorescent sensors have been extensively employed in efficient energy utilization and environment protection. In this work, an amino-decorated metal–organic framework [Cd(3-NH2-pba)2]4·8DMF (3-NH2...

Reuse of Predesigned Dual-Functional Metal Organic Frameworks (DF-MOFs) after Heavy Metal Removal

Designing porous and functionalized adsorbents and achieving high efficiency in heavy metals removal from wastewater is in the spotlight of environmental science. On the other hand, upon removal, adsorbents are still highly hazardous requiring that great care be taken in its packaging, transporting and storing. A fundamental route in the synthesis of functional extended structures is the ability to combine different chemical entities in a controlled way in order to achieve high performance. Herein, we report the systematic design of dual-functionalized metal organic framework (TMU-81) by incorporating sulfonyl and amide groups for the removal of Cd(II), Cu(II) and Cr(II) ions from simulated aqueous solutions. TMU-81 showed significant enhancement in heavy metals uptake suggesting that the strong host − guest interactions between cations and the donor sites play a major role in adsorption process. The maximum adsorption capacity for Cd2+ was 526 mg/g which is among the highest values reported for similar MOFs and other porous materials. The good performance in uptake and selectivity of TMU-81 can be attributed to the network structure that shaping the void, create mono-dimensional channels, decorated by exposed oxygen atom sites selective for Cadmium ion. Environmental “compatibility” of a treated MOFs was studied in order to evaluate its possible recycling as a new template for different applications by using pyrolysis method. Engineering of the pore surface provides a potential for MOF with a hybrid interface to act as a versatile tool for the design of multifunctional nanoparticles to meet specific application requirements.

Visible-Light-Driven Rotation of Molecular Motors in a Dual-Function Metal-Organic Framework Enabled by Energy Transfer.

The visible-light-driven rotation of an overcrowded alkene-based molecular motor strut in a dual-function metal–organic framework (MOF) is reported. Two types of functional linkers, a palladium–porphyrin photosensitizer and a bispyridine-derived molecular motor, were used to construct the framework capable of harvesting low-energy green light to power the rotary motion. The molecular motor was introduced in the framework using the postsynthetic solvent-assisted linker exchange (SALE) method, and the structure of the material was confirmed by powder (PXRD) and single-crystal X-ray (SC-XRD) diffraction. The large decrease in the phosphorescence lifetime and intensity of the porphyrin in the MOFs upon introduction of the molecular motor pillars confirms efficient triplet-to-triplet energy transfer between the porphyrin linkers and the molecular motor. Near-infrared Raman spectroscopy revealed that the visible light-driven rotation of the molecular motor proceeds in the solid state at rates similar to those observed in solution.

Illuminating a Practical Solution to Clothing Protection from Mustard Gas

Lee et al. reported the first metal-organic framework (MOF)-fiber composite for the catalytic detoxification of a mustard gas simulant. The development of such wearable catalytic materials is an important step toward developing protection equipment that can simultaneously detoxify several chemical warfare agents (CWAs) under ambient conditions.

Protective Fabrics: Metal-Organic Framework Textiles for Rapid Photocatalytic Sulfur Mustard Simulant Detoxification

Summary Metal-organic frameworks (MOFs) can catalyze toxic chemical decontamination, but new MOF materials and synthesis strategies are needed to improve performance, particularly in field-usable MOF-textile formats. This article reports for the first time the exceptional photocatalytic reactivity of Al-PMOF (Al-porphyrin-based MOF), composed of an earth-abundant metal-containing Al(OH)O4 cluster bridged by H2TCPP (5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) chromophores, against the toxic sulfur mustard simulant 2-chloroethyl ethyl sulfide (CEES) under visible-light irradiation. Furthermore, Al-PMOF is strongly immobilized into polymeric fibers via well-controlled Al2O3 solid film conversion using dimethylformamide/water cosolvent. The approach enables a secure integration of conformal Al-PMOF films onto polymer fibers at a relatively low synthesis temperature (120°C). In addition, on a per-unit mass of MOF basis, the surface-bound Al-PMOF films enable extremely rapid CEES detoxification turnover frequency, up to 170 mol CEES mol chromophore − 1 min − 1 , more than 10-fold faster than the best MOF powders and 2-fold better than MOF films reported to date.

Construction of a Dual-Function Metal–Organic Framework: Detection of Fe3+, Cu2+, Nitroaromatic Explosives, and a High Second-Harmonic Generation Response

In this work, an Eu3+-based dual-function metal–organic framework [Eu2L2(DMF)(H2O)2]·2DMF·H2O [H3L = 5-(1-carboxynaphthalen-4-yl)benzene-1,3-dioic acid] (1) has been successfully constructed. This ...

The targeted design of dual-functional metal-organic frameworks (DF-MOFs) as highly efficient adsorbents for Hg2+ ions: synthesis for purpose.

Designing adsorbents with accessible chelating sites and achieving high contaminant purification efficiency are still important to overcome environmental remediation challenges. As one of the significant global concerns, the presence of heavy metal ions in the environment has attracted increasing attention due to their toxicity, carcinogenicity, and bioaccumulation in the food chain. Herein, we performed a targeted design of a new dual-functionalized metal-organic framework (DF-MOF) by incorporating different percentages of the N1,N3-di(pyridine-4-yl) malonamide ligand (S) into urea-containing MOF (TMU-32); the produced material was labeled as TMU-32S (with 33%, 65%, and 100% incorporation percentages). Designing DF-MOF is our "design-for-purpose" approach for the decoration of MOF walls by suitable functional groups, resulting in high removal capacity of heavy metal ions. Among the TMU-32S series having different concentrations of the S ligand, TMU-32S-65% demonstrated exceptional Hg2+ ion selectively. To the best of our knowledge, this is the first report of mixed urea-malonamide-based MOF, which provides a proper coordination site to strongly coordinate with Hg2+ ions, along with 1428 mg g-1 maximum adsorption capacity. Generally, we attributed the impressive implementation of TMU-32S-65% to the synergistic effects of both hydrophilic chelating urea and the malonamide functional group. Hence, the results reported in this work indicate the exceptional potential of DF-MOFs for the high accomplishment of environmental remediation.

Dual Functionalized Cages in Metal–Organic Frameworks via Stepwise Postsynthetic Modification

The introduction of bi- or multifunctionality into different cages of metal–organic frameworks (MOFs) has been of great interest because such MOF materials can demonstrate unique properties for various applications. Herein, we report a general strategy for creating different types of functionalized cages in MOFs by exerting control of the size of cage windows. Selective cage decoration was thereby enabled in such a manner that dual functional MOFs with different types of cages and pores can be created. The resultant different pore function MOF, DPF-MOF, is illustrated as a “proof of concept” in MOF MIL-101-Cr. An intermediate of a cascade reaction was successfully trapped and controlled the desired reaction direction. This DPF-MOF represents a new type of platform that, by trapping intermediates during the reaction processes, enhances our fundamental understanding of reaction chemistry in porous materials.

Dual-Function Metal-Organic Framework as a Versatile Catalyst for Detoxifying Chemical Warfare Agent Simulants.

The nanocrystals of a porphyrin-based zirconium(IV) metal-organic framework (MOF) are used as a dual-function catalyst for the simultaneous detoxification of two chemical warfare agent simulants at room temperature. Simulants of nerve agent (such as GD, VX) and mustard gas, dimethyl 4-nitrophenyl phosphate and 2-chloroethyl ethyl sulfide, have been hydrolyzed and oxidized, respectively, to nontoxic products via a pair of pathways catalyzed by the same MOF. Phosphotriesterase-like activity of the Zr6-containing node combined with photoactivity of the porphyrin linker gives rise to a versatile MOF catalyst. In addition, bringing the MOF crystals down to the nanoregime leads to acceleration of the catalysis.