Synthesis of novel cellulose- based antibacterial composites of Ag nanoparticles@ metal-organic frameworks@ carboxymethylated fibers

A novel cellulose-based antibacterial material, namely silver nanoparticles@ metal-organic frameworks@ carboxymethylated fibers composites (Ag NPs@ HKUST-1@ CFs), was synthesized. The results showed that the metal-organic frameworks (HKUST-1) were uniformly anchored on the fiber's surfaces by virtue of complexation between copper ions in HKUST-1 and carboxyl groups on the carboxymethylated fibers (CFs). The silver nanoparticles (Ag NPs) were immobilized and well-dispersed into the pores and/or onto the surfaces of HKUST-1 via in situ microwave reduction, resulting in the formation of novel Ag NPs@ HKUST-1@ CFs composites. The antibacterial assays showed that the as-prepared composites exhibited a much higher antibacterial activity than Ag NPs@ CFs or HKUST-1@ CFs samples.

Co₂ and Co₃ Mixed Cluster Secondary Building Unit Approach toward a Three-Dimensional Metal-Organic Framework with Permanent Porosity

Large and permanent porosity is the primary concern when designing metal-organic frameworks (MOFs) for specific applications, such as catalysis and drug delivery. In this article, we report a MOF Co11(BTB)₆(NO₃)₄(DEF)₂(H₂O)14 (1, H₃BTB = 1,3,5-tris(4-carboxyphenyl)benzene; DEF = N,N-diethylformamide) via a mixed cluster secondary building unit (SBU) approach. MOF 1 is sustained by a rare combination of a linear trinuclear Co₃ and two types of dinuclear Co₂ SBUs in a 1:2:2 ratio. These SBUs are bridged by BTB ligands to yield a three-dimensional (3D) non-interpenetrated MOF as a result of the less effective packing due to the geometrically contrasting SBUs. The guest-free framework of 1 has an estimated density of 0.469 g cm-3 and exhibits a potential solvent accessible void of 69.6% of the total cell volume. The activated sample of 1 exhibits an estimated Brunauer-Emmett-Teller (BET) surface area of 155 m² g-1 and is capable of CO₂ uptake of 58.61 cm³ g-1 (2.63 mmol g-1, 11.6 wt % at standard temperature and pressure) in a reversible manner at 195 K, showcasing its permanent porosity.

Photothermal Activation of Metal-Organic Frameworks Using a UV-Vis Light Source

Metal-organic frameworks (MOFs) usually require meticulous removal of the solvent molecules to unlock their potential porosity. Herein, we report a novel one-step method for activating MOFs based on the photothermal effect induced by directly irradiating them with a UV-vis lamp. The localized light-to-heat conversion produced in the MOF crystals upon irradiation enables a very fast solvent removal, thereby significantly reducing the activation time to as low as 30 min and suppressing the need for time-consuming solvent-exchange procedures and vacuum conditions. This approach is successful for a broad range of MOFs, including HKUST-1, UiO-66-NH₂, ZIF-67, CPO-27-M (M = Zn, Ni, and Mg), Fe-MIL-101-NH₂, and IRMOF-3, all of which exhibit absorption bands in the light emission range. In addition, we anticipate that this photothermal activation can also be used to activate covalent organic frameworks (COFs).

Sensitive electrogenerated chemiluminescence biosensors for protein kinase activity analysis based on bimetallic catalysis signal amplification and recognition of Au and Pt loaded metal-organic frameworks nanocomposites

In this work, a novel and sensitive electrogenerated chemiluminescence (ECL) biosensor for protein kinase A (PKA) activity analysis and relevant inhibitor screening was proposed based on bimetallic catalysis signal amplification and recognition of Au and Pt nanoparticles loaded metal-organic frameworks (Au&Pt@UiO-66) nanocomposite. After being phosphorylated by PKA in the presence of ATP, Au&Pt@UiO-66 probes were specifically chelated to the modified electrode by forming Zr-O-P bonds between the surface defects of UiO-66 and the phosphorylated kemptide. Due to the high synergistic catalysis of Au&Pt@UiO-66 nanocomposites to the luminol-H₂O₂ reaction, the ECL signal of luminol was greatly enhanced. Moreover, UiO-66 afford numerous Zr defect sites for high efficient phosphate group recognition, and can also prevent the nanoparticles from aggregating during catalytic reactions. Thus, the excellent performance of the ECL biosensor with high sensitivity and superior stability was obtained. Under the optimized conditions, the detection limit for PKA activity was 0.009 UmL^-1 (S/N = 3). Meanwhile, the ECL biosensor was successfully applied in inhibitor screening and cell lysates PKA activity analysis, showing great promise in kinase related research.

A cluster-based mesoporous Ti-MOF with sodalite supercages

The cooperative assembly of a hexagonal column shaped [Ti₆O₆][ⁱPrO]₆⁶⁺ cluster and rhomboid Cu₂I₂ dimers using isonicotinic acid results in an unprecedented three-dimensional (3D) highly crystalline cluster-based Ti-MOF that features both giant sodalite cages with an inner diameter of 2.8 × 3.2 nm² and 3D open square channels.

Porous aromatic framework with mesopores as a platform for a super-efficient heterogeneous Pd-based organometallic catalysis

A strategy using a mesoporous amine-tagged porous aromatic framework (PAF70-NH₂ ) to immobilize a palladium (Pd)-based molecular catalyst has been developed. The resulting immobilized catalyst PAF70-Pd, in which the framework is entirely constructed by phenyl rings linked with stable carbon-carbon bonds, has high structural rigidity and stability. Compared with the known porous organic material immobilized Pd-based catalysts, PAF70-Pd has the highest Pd content so far. Moreover, PAF70-Pd has extremely high catalytic activity with good size selectivity and very easy recyclability in catalyzing the Suzuki-Miyaura coupling reaction. In the current system, the catalyst loading could be as low as 0.001 mol% and the TOF value could go up to 28 800 h^-1 which is far higher than those of the known porous organic material immobilized Pd-based catalysts. In order to elucidate the particularly high catalytic efficiency of PAF70-Pd, we prepared PAF1-Pd from PAF1-NH₂ for comparison. PAF1-Pd has a higher Pd content than PAF70-Pd. However, due to the absence of large enough mesopores in PAF1-NH₂ , PAF1-Pd has almost no catalytic activity under the same conditions, which definitely demonstrated that the intrinsic mesoporosity of PAF70-NH₂ plays a crucial role in the superb catalytic efficiency of PAF70-Pd. This strategy to immobilize Pd-based molecular catalysts has very good expansibility to be applied in the immobilization of different organometallic catalysts into the pores of PAFs, which also has very high potential in the chemical and pharmaceutical industry.

Preparation of Dual-Emitting Ln@UiO-66-Hybrid Films via Electrophoretic Deposition for Ratiometric Temperature Sensing

Engineering novel dual-emitting metal-organic frameworks (MOFs) with wide emission ranges for application as ratiometric temperature sensors is still a challenge. In this paper, two novel dual-emitting MOFs with intergrated lanthanide metals and luminescent ligand in a UiO-66-type structure, named Ln@UiO-66-Hybrid, were prepared via the combination of postsynthetic modification and postsynthetic exchange methods. Subsequently, the as-synthesized MOFs were deposited onto fluorine tin oxide substrates through electrophoretic deposition by taking advantage of the charges from the unmodified carboxylic groups of the MOFs. The as-prepared Tb@UiO-66-Hybrid and Eu@UiO-66-Hybrid films were applied to detect temperature changes. The resulting Tb@UiO-66-Hybrid film exhibited good temperature-sensing properties with a relative sensitivity of up to 2.76% K^-1 in the temperature range of 303-353 K. In addition, the Eu@UiO-66-Hybrid film showed excellent temperature-sensing performance based on the energy transfer between the luminescent ligand (H₂NDC) and europium ions with a relative sensitivity of up to 4.26% K^-1 in the temperature range of 303-403 K.

Single Pt Atoms Confined into a Metal-Organic Framework for Efficient Photocatalysis

It is highly desirable yet remains challenging to improve the dispersion and usage of noble metal cocatalysts, beneficial to charge transfer in photocatalysis. Herein, for the first time, single Pt atoms are successfully confined into a metal-organic framework (MOF), in which electrons transfer from the MOF photosensitizer to the Pt acceptor for hydrogen production by water splitting under visible-light irradiation. Remarkably, the single Pt atoms exhibit a superb activity, giving a turnover frequency of 35 h^-1 , ≈30 times that of Pt nanoparticles stabilized by the same MOF. Ultrafast transient absorption spectroscopy further unveils that the single Pt atoms confined into the MOF provide highly efficient electron transfer channels and density functional theory calculations indicate that the introduction of single Pt atoms into the MOF improves the hydrogen binding energy, thus greatly boosting the photocatalytic H₂ production activity.

Diffusion Control in the in Situ Synthesis of Iconic Metal-Organic Frameworks within an Ionic Polymer Matrix

Ionic polymers that possess ion-exchangeable sites have been shown to be a greatly useful platform to fabricate mixed matrices (MMs) where metal-organic frameworks (MOFs) can be in situ synthesized, although the in situ synthesis of MOF has been rarely studied. In this study, alginate (ALG), an anionic green polymer that possesses metal-ion-exchangeable sites, is employed as a platform of MMs for the in situ synthesis of iconic MOFs, HKUST-1, and MOF-74(Zn). We demonstrate for the first time that the sequential order of supplying MOF ingredients (metal ion and deprotonated ligand) into the alginate matrix leads to substantially different results because of a difference in the diffusion of the MOF components. For the examples examined, whereas the infusion of BTC^3- ligand into Cu²⁺-exchanged ALG engendered the eggshell-shaped HKUST-1 layers on the surface of MM spheres, the infusion of Cu²⁺ ions into BTC^3--included alginate engendered the high dispersivity and junction contact of HKUST-1 crystals in the alginate matrix. This fundamental property has been exploited to fabricate a flexible MOF-containing mixed matrix membrane by coincorporating poly(vinyl alcohol). Using two molecular dyes, namely, methylene blue and rhodamine 6G, further, we show that this in situ strategy is suitable for fabricating an MOF-MM that exhibits size-selective molecular uptake.

Robust heterometallic MOF catalysts for the cyanosilylation of aldehydes

Zn²⁺/Cu²⁺ ions are doped into a Mn²⁺ based frail MOF to form robust heterometallic MOFs catalysts for the cyanosilylation of aldehydes.

Controlled synthesis of novel one-dimensional structured ZIFs via supramolecular self-assemblies

Various 1D ZIF-8 nanomaterials have been synthesized via the self-templates of supramolecular self-assemblies, which exhibit hierarchical pores and high surface area. The resultant microstructures could be applied as excellent drug delivery vehicles and also as excellent carriers for enzymes with remarkable enzymatic activity.

Trace water accelerating the CO2 cycloaddition reaction catalyzed by an indium–organic framework

A unique four-fold interpenetrated In–MOF is utilized as a catalyst in the chemical fixation of CO₂, and the catalytic activity is promoted by trace water.

A new transformation of coumarins via direct C–H bond activation utilizing an iron–organic framework as a recyclable catalyst

A new mixed-linker iron-based MOF VNU-20 [Fe₃(BTC)(NDC)₂·6.65H₂O] was solvothermally synthesized, and utilized as catalyst for the coupling transformation of coumarins with N,N-dimethylanilines.

Controlled flexibility of porous coordination polymers by shifting the position of the –CH3 group around coordination sites and their highly efficient gas separation

By adjusting the position of the methyl group, we found significant changes in the structural flexibility of the obtained PCPs, which also showed good gas separation ability.

Homodimerization of 2H-chromenes catalyzed by Brønsted-acid derived UiO-66 MOFs

Brønsted acid UiO-66 MOFs were prepared for the efficient homo-dimerization of 2H-chromenes, which involves a tandem rearrangement/hetero-Diels–Alder reaction sequence.

Two luminescent transition-metal–organic frameworks with a predesigned ligand as highly sensitive and selective iron(iii) sensors

The water-stable imidazole dicarboxylated-based MOFs are excellent luminescent probes for the Fe³⁺ ion in an aqueous solution.

A facile 2H-chromene dimerization through an ortho-quinone methide intermediate catalyzed by a sulfonyl derived MIL-101 MOF

An efficient homo-dimerization of 2H-chromenes was achieved in high yield and diastereoselectivity using a MIL-101–SO₃H MOF catalyst.

An efficient and sustainable catalytic reduction of carbon–carbon multiple bonds, aldehydes, and ketones using a Cu nanoparticle decorated metal organic framework

Economical, reusable, eco-friendly sustainable process is reported that involve low amount of hydrazine hydrate.

Operando study of palladium nanoparticles inside UiO-67 MOF for catalytic hydrogenation of hydrocarbons

Formation of Pd nanoparticles inside UiO-67 MOF was monitored by in situ X-ray absorption and diffraction.

Polyoxometalate-encapsulated twenty-nuclear silver-tetrazole nanocage frameworks as highly active electrocatalysts for the hydrogen evolution reaction

Two unprecedented polyoxometalate (POM)-encapsulated twenty-nuclear silver-tetrazole nanocage frameworks have been successfully synthesized, which exhibit high activity in the hydrogen evolution reaction.

2-D porous Ni3N–Co3N hybrids derived from ZIF-67/Ni(OH)2 sheets as a magnetically separable catalyst for hydrogenation reactions

The synergistic nitridation of Ni(OH)₂ and ZIF-67 during the treatment of ZIF-67/Ni(OH)₂ sheets is demonstrated to be important to forming 2-D porous Ni₃N–Co₃N hybrids that can be used as a magnetically separable catalyst for hydrogenation reactions.

Synergistic effect of adsorption coupled with catalysis based on graphene-supported MOF hybrid aerogel for promoted removal of dyes

A three-dimensional MIL-100(Fe)/graphene hybrid aerogel (MG-HA) was fabricated via in situ decoration of graphene oxide with MIL-100(Fe) nanoparticles. The resulting MG-HA with interconnected pore structure was applied as both adsorbent and catalyst for the removal of methylene blue (MB) from aqueous solutions. The result shows that the saturation adsorption capacity of the MG-HA was as high as 333.33 mg g⁻¹, exceeding that of both the corresponding pristine graphene aerogel and MIL-100(Fe) nanoparticles. In the presence of hydrogen peroxide, MG-HA further exhibited catalytic degradation ability. The dual functions achieved a synergistic effect leading to the quick and complete removal of MB. The benefit was revealed in the treatment of high concentration of pollutants without leaving secondary pollution. The merit was intuitively demonstrated in the instant removal of MB through a model separation device in comparison with a series of common adsorbents. A feasible mathematic model was built based on the synergistic adsorption/catalysis process, which perfectly fitted the experimental data. A pseudo-second-order adsorption process and pseudo-first-order catalytic degradation kinetics were revealed. Additionally, the MG-HA was able to retain 93.4% of its initial removal efficiency after 5 cycles of application. The macro-material body can be easily separated and reused without a time-consuming and high-cost recycling process.

A three-dimensional MIL-100(Fe)/graphene hybrid aerogel was fabricated for highly efficient removal of dye pollutants via synergistic adsorption and degradation.

Encapsulating surface-clean metal nanoparticles inside metal–organic frameworks for enhanced catalysis using a novel γ-ray radiation approach

A facile, efficient and universal γ-radiation strategy has been developed to incorporate surface-clean metal nanoparticles into metal–organic frameworks exhibiting remarkable catalytic activity and stability.

Seven luminescent metal–organic frameworks constructed from 5-(triazol-1-yl)nicotinic acid: luminescent sensors for CrVI and MnO4− ions in an aqueous medium

Seven new luminescent metal–organic frameworks were assembled and complex 2 shows high selectivity and sensitivity for CrO₄²⁻, Cr₂O₇²⁻ and MnO₄⁻ ions with low detection limits.

Catalysis and photocatalysis by metal organic frameworks

This review aims to provide different strategies employed to use MOFs as solid catalysts and photocatalysts in organic transformations.

Copper-catalyzed one-pot domino reactions via C–H bond activation: synthesis of 3-aroylquinolines from 2-aminobenzylalcohols and propiophenones under metal–organic framework catalysis

A Cu₂(OBA)₂(BPY) metal–organic framework was utilized as a productive heterogeneous catalyst for the synthesis of 3-aroylquinolines via one-pot domino reactions of 2-aminobenzylalcohols with propiophenones. This Cu-MOF was considerably more active towards the one-pot domino reaction than a series of transition metal salts, as well as nano oxide and MOF-based catalysts. The MOF-based catalyst was reusable without a significant decline in catalytic efficiency. To the best of our knowledge, the transformation of 2-aminobenzylalcohols to 3-aroylquinolines was not previously reported in the literature, and this protocol would be complementary to previous strategies for the synthesis of these valuable heterocycles.

Cu₂(OBA)₂(BPY) metal–organic framework was utilized as a productive heterogeneous catalyst for the synthesis of 3-aroylquinolines via one-pot domino reactions of 2-aminobenzylalcohols with propiophenones.

Hybridization of MOFs and COFs: A New Strategy for Construction of MOF@COF Core-Shell Hybrid Materials

The exploration of new porous hybrid materials is of great importance because of their unique properties and promising applications in separation of materials, catalysis, etc. Herein, for the first time, by integration of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), a new type of MOF@COF core-shell hybrid material, i.e., NH₂ -MIL-68@TPA-COF, with high crystallinity and hierarchical pore structure, is synthesized. As a proof-of-concept application, the obtained NH₂ -MIL-68@TPA-COF hybrid material is used as an effective visible-light-driven photocatalyst for the degradation of rhodamine B. The synthetic strategy in this study opens up a new avenue for the construction of other MOF-COF hybrid materials, which could have various promising applications.

A size-matched POM@MOF composite catalyst for highly efficient and recyclable ultra-deep oxidative fuel desulfurization

A composite of Keggin-type phosphotungstic acid (H₃PW₁₂O₄₀) encapsulated in sized-matched metal–organic framework UiO-67 (PW₁₂@UiO-67) was prepared as a heterogeneous catalyst for extractive and catalytic oxidative desulfurization systems (ECODS).

Assembly of ZnII-coordination polymers constructed from benzothiadiazole functionalized bipyridines and V-shaped dicarboxylic acids: topology variety, photochemical and visible-light-driven photocatalytic properties

Photocatalytic properties of four benzothiadiazole functionalized coordination polymers have been reported.

Metal coordination and metal activation abilities of commonly unreactive chloromethanes toward metal–organic frameworks

The commonly inert chloromethanes, dichloromethane and trichloromethane, can exchange other solvents bonded at open coordination sites in metal–organic frameworks, providing a new route to activate the open coordination sites for subsequent use in applications.

Syntheses of copper–iodine cluster-based frameworks for photocatalytic degradation of methylene blue

Cu–I cluster-based MOFs show a broad range of absorption in the visible region and exhibit excellent photocatalytic degradation of methylene blue dye under visible light.

Visible light-enhanced thermal decomposition performance of ammonium perchlorate with a metal–organic framework-derived Ag-embedded porous ZnO nanocomposite

An Ag-embedded porous ZnO nanocomposite (Ag–ZnO NC) fabricated using an MOF exhibits high catalytic activity for the thermal decomposition of AP under the assistance of visible light.

Photonic functional metal–organic frameworks

The recent progress in photonic MOFs for luminescence sensing, white-light emission, photocatalysis, nonlinear optics, lasing devices, and biomedicine is summarized.

Defective Pt nanoparticles encapsulated in mesoporous metal–organic frameworks for enhanced catalysis

Highly ultrafine defective Pt nanoparticles (NPs) encapsulated in the mesopores of MIL-101 (Pt(Co)@MIL-101) were achieved for the first time through a chemical dealloying approach. The obtained material could provide more active sites to contact reactants and showed superior catalytic activity towards the hydrogenation of nitroarenes under mild conditions.

Controllable synthesis of isoreticular pillared-layer MOFs based on N-rich triangular prism building units: gas adsorption and luminescent properties

Isoreticular 1–4 MOFs with rare lon topologies have been rationally synthesized based on novel trigonal-prism building units.

Stable metal–organic frameworks as a host platform for catalysis and biomimetics

Recent years have witnessed the exploration and synthesis of an increasing number of metal–organic frameworks (MOFs). The utilization of stable MOFs as a platform for catalysis and biomimetics is discussed.