MOF Catalyst Research Articles

Nucleophilic trifluormethylation of aryl boronic acid under heterogeneous Cu(INA)2 catalysis at room temperature: The catalytic copper-based protocol

Herein, we described the first heterogeneous and catalytic protocol for nucleophilic trifluoromethylation of aryl boronic acids. In particular, the synthesized metal-organic framework copper isonicotinate Cu(INA) 2 [INA=1,4-(NC5H4CO2)] exhibited exceptional catalytic activity toward the trifluoromethylation of boronic acids. Optimal conditions involve the use of Cu(INA)2 catalyst (30% mol), nucleophilic trifluoromethyltrimethylsilane (TMSCF3) and CsF reagent in 1,2-dichloroethane (DCE) solvent at room temperature in 2h. Molecular oxygen was employed as teminal oxidant. Noteworthily, reported conditions for same reactions required stoichiometric amount of homogeneous copper salts. Additionally, preliminary investigation of structure/activity relationship supported that weak interaction between copper centers and the presence of free carboxylate oxygen atoms within the network structure favored the trifluoromethylation. Subsequently, Cu(INA) 2 possessed higher activity than other copper-based homogeneous/heterogeneous catalysts and other MOFs catalysts. Leaching tests confirmed the heterogeneity of Cu(INA)2 during reaction. Thus, almost similar reaction yield was still obtained at 6th run.

MOF catalysts in biomass upgrading towards value-added fine chemicals

The development of new synthetic routes from biomass sources towards already existing molecules, which are then called bio-based molecules, or the transformation of biomass into new building blocks and materials will be of great impact. This review presents a critical comparison between MOFs and other catalysts (e.g. zeolites) for biomass transformation.

Photoswitching storage of guest molecules in metal–organic framework for photoswitchable catalysis: exceptional product, ultrahigh photocontrol, and photomodulated size selectivity

We present a novel MOF catalyst, which shows both ultrahigh photocontrol in catalytic activity and selectivity.

Upgrading of palmitic acid over MOF catalysts in supercritical fluid of n-hexane

The addition of phosphotungstic acid (PTA) to the synthesis mixture of PdCu@FeIII–MOF-5 yields the direct encapsulation of PTA inside the MOF structure (i.e. PTA@PdCu@FeIII–MOF-5) through a facile solvothermal approach.

Inverse relationship of dimensionality and catalytic activity in CO2transformation: a systematic investigation by comparing multidimensional metal–organic frameworks

The correlation between dimensionality and active sites on deciding the catalytic performance of an MOF catalyst in CO2–epoxide cycloaddition reactions has been studied.

An ultrastable zirconium-phosphonate framework as bifunctional catalyst for highly active CO2 chemical transformation.

A zirconium-phosphonate network, as a bifunctional catalyst for carbon dioxide (CO2)/epoxide coupling reaction, exhibits very high activity that is superior to most documented metal-organic framework (MOF)-based catalysts. Furthermore, it possesses extraordinary tolerance to extremely harsh conditions, such as aqua regia. This paper describes the use of metal phosphonate as a new MOF applied to CO2 transformation.

In-situ Growth of Ultrathin ZIF-67 Nanosheets on Conductive Ti@TiO2/CdS Substrate for High-efficient Electrochemical Catalysis

Efficient charge transport is a key to the successful design of electrocatalyst. In this work, we report the in-situ growth of ultrathin MOF material (ZIF-67) nanosheets on conductive Ti@TiO2/CdS substrate for high-efficient electrochemical catalysis due to optimized charge transport. The ultrathin ZIF-67 nanosheets were grown on Ti@TiO2/CdS nanowire array substrates resulting unique 3D hierarchical structures, which were investigated as electrocatalyst for the oxygen-evolution reaction (OER) and H2O2 oxidation. The nanowire-supported ZIF-67 nanosheet electrode shows remarkable electrocatalytic activity and excellent stability toward OER and H2O2 oxidation, which can be explained by the rapid electron transport along the 1D Ti@TiO2/CdS nanowire to Ti substrates, large electrochemical active surface area and the rising valence state of Co ions induced by electronegative N atom in imidazole ligands. Compared with other MOFs catalysts, we obtained a very small Tafel slope (42mV/dec) and a small overpotential (0.41V) at 10mAcm−2 for OER. When used for H2O2 detection, the electrode gave a high sensitivity of 1214.3μAmM−1cm−2, a wide linear range of 5μM–14mM and a low detection limit of 1.11μM. This research suggests that the in-situ grown nanostructure of Ti@TiO2/CdS/ZIF-67 hold great promise for advanced electrocatalytic electrode in water oxidation and H2O2 detection.

Detoxification of Chemical Warfare Agents Using a Zr6 -Based Metal-Organic Framework/Polymer Mixture.

Owing to their high surface area, periodic distribution of metal sites, and water stability, zirconium-based metal-organic frameworks (Zr6 -MOFs) have shown promising activity for the hydrolysis of nerve agents GD and VX, as well as the simulant, dimethyl 4-nitrophenylphosphate (DMNP), in buffered solutions. A hurdle to using MOFs for this application is the current need for a buffer solution. Here the destruction of the simulant DMNP, as well as the chemical warfare agents (GD and VX) through hydrolysis using a MOF catalyst mixed with a non-volatile, water-insoluble, heterogeneous buffer is reported. The hydrolysis of the simulant and nerve agents in the presence of the heterogeneous buffer was fast and effective.

Heterostructured Au NPs/CdS/LaBTC MOFs Photoanode for Efficient Photoelectrochemical Water Splitting: Stability Enhancement via CdSe QDs to 2D-CdS Nanosheets Transformation.

The electrochemical stability of MOFs in aqueous medium is most essential for MOFs based electrocatalysts for hydrogen production via water splitting. Since most MOFs suffer from instability issues in aqueous systems, there is enormous demand for electrochemically stable MOFs catalysts. Herein, we have developed a simple postsynthesis surface modification protocol for La (1,3,5-BTC) (H2O)6 metal-organic frameworks (LaBTC MOFs) using Mercaptopropionic acid (MPA), to attain electrochemical stability in aqueous mediums. The MPA treated LaBTC MOFs exhibited better stability than the bare LaBTC. Further, to facilitate light harvesting properties of LaBTC MOFs, Au nanoparticles (NPs) and CdSe quantum dots (QDs) are functionalized on LaBTC. The sensitization of LaBTC with Au NPs and CdSe QDs enhances the light harvesting properties of LaBTC in the visible region of solar spectrum. Using as a photoanode, the electrode generates the current density of ∼80 mA/cm(2) at 0.8 V (vs Ag/AgCl) during photoelectrochemical water splitting. The heterostructured LaBTC photoanode demonstrates the long-term stability for the period of 10 h. The electrode post-mortem analysis confirms the conversion of CdSe QDs into single crystalline 2D-CdS nanosheets. The present investigation reveals that CdS nanosheets together with SPR Au NPs improve the photoelectrochemical water splitting activity and stability of LaBTC MOFs.

Au@Cu(II)-MOF: Highly Efficient Bifunctional Heterogeneous Catalyst for Successive Oxidation–Condensation Reactions

A new composite Au@Cu(II)-MOF catalyst has been synthesized via solution impregnation and full characterized by HRTEM, SEM-EDS, XRD, gas adsorption-desorption, XPS, and ICP analysis. It has been shown here that the Cu(II)-framework can be a useful platform to stabilize and support gold nanoparticles (Au NPs). The obtained Au@Cu(II)-MOF exhibits a bifunctional catalytic behavior and is able to promote selective aerobic benzyl alcohol oxidation-Knoevenagel condensation in a stepwise way.

Interplay between hydrophobicity and basicity toward the catalytic activity of isoreticular MOF organocatalysts

Four MOF catalysts showing different hydrophobic characters around the basic reaction center showed subtle substrate selectivity in aldol-type condensation reaction.

An N-heterocyclic carbene based MOF catalyst for Sonogashira cross-coupling reaction

The post-synthetic modification of azolium containing MOFs generated a new heterogeneous N-heterocyclic carbene catalyst (1-Pd), which is very active for Sonogashira cross coupling reaction.

Iodine-Loaded Ni(II)-MOF Catalyst for Silylcyanation of Benzaldehyde

Key words metal-organic framework - silylcyanation - aldehydes - heterogeneous catalysis

One-pot synthesis of hydrazono-sulfonamide adducts using Cu(BTC) MOF catalyst and their remarkable AIEE properties: unprecedented copper(ii)-catalyzed generation of ketenimine

One pot & simple operation; short reaction time; no column purification; very less catalyst loading; scalable.

MOF as a syringe pump for the controlled release of iodine catalyst in the synthesis of meso-thienyl dipyrromethanes

In a new concept, an iodine loaded amine functionalized MOF was employed as a syringe pump for the slow release of iodine as a catalyst in the synthesis of thienyl dipyrromethanes under ambient conditions and turned out to be successful. The catalytic activities were compared with an isoreticular non-functionalized MOF and other conventional catalysts.

An lcy-topology amino acid MOF as eco-friendly catalyst for cyclic carbonate synthesis from CO2: Structure-DFT corroborated study

A Zn(ii)-amino acid MOF catalyst and its use for CO2fixation are reported, in addition to corresponding structure-topology-DFT studies.

Bifunctional MOF heterogeneous catalysts based on the synergy of dual functional sites for efficient conversion of CO2under mild and co-catalyst free conditions

We report two ionic liquids functionalized CUSs-containing MOF catalysts, which exhibit high catalyst activity for the cycloaddition of CO2and epoxide.

Ag–Cu–BTC prepared by postsynthetic exchange as effective catalyst for selective oxidation of toluene to benzaldehyde

A mixed-node MOF catalyst Ag–Cu–BTC was prepared by postsynthetic exchange (PSE) method. It is believed that PSE method can realize isomorphous replacement of Ag ion to framework Cu ion in Cu–BTC successfully. The catalytic performance of Ag–Cu–BTC was investigated via selective oxidation of toluene to benzaldehyde by molecular oxygen in the absence of solvent and initiator. This catalyst exhibits good catalytic performance: on the premise of keeping highly selective catalysis of Cu–BTC for toluene oxidizing to benzaldehyde, the introduction of Ag (Ag content is 2.76wt.%) can promote toluene conversion from 6.5% to 12.7%.

Oxidation of Secondary Alcohols with UiO-66-Cr MOF Catalyst

Oxidation of Secondary Alcohols with UiO-66-Cr MOF Catalyst

Immobilization of Pd(II) on MOFs as a highly active heterogeneous catalyst for Suzuki–Miyaura and Ullmann-type coupling reactions

Palladium chloride was successfully immobilized on MOF-253, a MOF material with un-coordinated 2,2′-bipyridine moieties, through post-synthetic modification. The coordination interaction between the 2,2′-bipyridine moieties and Pd cations in the MOF-253·PdCl2 material was demonstrated by X-ray photoelectron spectroscopy (XPS) analysis. The prepared MOF-253·0.05PdCl2 was shown to be highly active, selective, and recyclable for the Suzuki–Miyaura cross-coupling and Ullmann homocoupling of a wide range of aryl halides including electron-rich and electron-poor aryl iodides/bromides, heteroaryl iodides, and even aryl chlorides, affording the corresponding biaryl compounds in good to excellent yields under mild reaction conditions. It is suggested that the 2,2′-bipyridine moieties in MOF-253 provide electron-rich environment for Pd(II) cations, and thus facilitate the initial adsorption and insertion of aryl halides molecules to Pd active sites during the carbon–carbon coupling reactions. Moreover, MOF-253·PdCl2 showed remarkably higher activity than the homogeneous Pd(bpy)Cl2 and PdCl2(CH3CN)2, which might be due to the presence of charge transfers between adjacent ligands and metals in the MOF catalyst. The superior catalytic performances of metal ions immobilized on MOFs to their homogenous counterparts might bring new opportunities in the development of highly efficient metal catalysts combining advantages of both homogeneous and heterogeneous catalysis.