Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

The Chemistry and Applications of Metal-Organic Frameworks

Great attention has been given to metal–organic frameworks (MOFs)-derived solid bases because of their attractive structure and catalytic performance in various organic reactions. The extraordinary skeleton structure of MOFs provides many possibilities for incorporation of diverse basic functionalities, which is unachievable for conventional solid bases. The past decade has witnessed remarkable advances in this vibrant research area; however, MOFs for heterogeneous basic catalysis have never been reviewed until now. Therefore, a review summarizing MOFs-derived base catalysts is highly expected. In this review, we present an overview of the recent progress in MOFs-derived solid bases covering preparation, characterization, and catalytic applications. In the preparation section, the solid bases are divided into two categories, namely, MOFs with intrinsic basicity and MOFs with modified basicity. The basicity can originate from either metal sites or organic ligands. Different approaches used for generation o...

Metal-Organic Frameworks for Heterogeneous Basic Catalysis.

Novel catalytic materials are highly demanded to perform a variety of catalytic organic reactions. MOFs combine the benefits of heterogeneous catalysis like easy post reaction separation, catalyst reusability, high stability and homogeneous catalysis such as high efficiency, selectivity, controllability and mild reaction conditions. The possible organization of active centers like metallic nodes, organic linkers, and their chemical synthetic functionalization on the nanoscale shows potential to build up MOFs particularly modified for catalytic challenges. In this review, we have summarized the recent research progress in heterogeneous catalysis by MOFs and their catalytic behavior in various organic reactions, highlighting the key features of MOFs as catalysts based on the active sites in the framework. Examples of their post functionalization, inclusion of active guest species and metal nanoparticles have been discussed. Finally, the use of MOFs as catalysts for asymmetric heterogeneous catalysis and stability of MOFs has been presented as separate sections.

Metal–organic frameworks: versatile heterogeneous catalysts for efficient catalytic organic transformations

The present review describes the use of metal–organic frameworks (MOFs) as porous matrices to embed metal nanoparticles (MNPs) and occasionally metal oxide clusters, which are subsequently used as heterogeneous catalysts. The review is organized according to the embedded metal including Pd, Au, Ru, Cu, Pt, Ni and Ag. Emphasis is also given in the various methodologies reported for the formation of the NPs and the characterization techniques. The reactions described with this type of solid catalysts include condensation, hydrogenations, carbon–carbon coupling, alcohol oxidations and methanol synthesis among others. Remaining issues in this field have also been indicated.

Catalysis by metal nanoparticles embedded on metal–organic frameworks

Defect engineering in metal–organic frameworks (MOFs) is an exciting concept for tailoring material properties, which opens up novel opportunities not only in sorption and catalysis, but also in controlling more challenging physical characteristics such as band gap as well as magnetic and electrical/conductive properties. It is challenging to structurally characterize the inherent or intentionally created defects of various types, and there have so far been few efforts to comprehensively discuss these issues. Based on selected reports spanning the last decades, this Review closes that gap by providing both a concise overview of defects in MOFs, or more broadly coordination network compounds (CNCs), including their classification and characterization, together with the (potential) applications of defective CNCs/MOFs. Moreover, we will highlight important aspects of “defect-engineering” concepts applied for CNCs, also in comparison with relevant solid materials such as zeolites or COFs. Finally, we discuss the future potential of defect-engineered CNCs.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/anie.201411540

Defect‐Engineered Metal–Organic Frameworks

A highly porous zeolite imidazolate framework (ZIF-8) was synthesized by a solvothermal method, and used as an efficient heterogeneous catalyst for the Knoevenagel reaction. The solid catalyst was characterized using a variety of different techniques, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic laser light scattering (DLS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), atomic absorption spectrophotometry (AAS), and nitrogen physisorption measurements. Quantitative conversion was achieved under mild conditions. The ZIF-8 catalyst could be facilely separated from the reaction mixture, and could be reused without significant degradation in catalytic activity. Furthermore, no contribution from homogeneous catalysis of active species leaching into reaction solution was detected.

Expanding Applications of Metal−Organic Frameworks: Zeolite Imidazolate Framework ZIF-8 as an Efficient Heterogeneous Catalyst for the Knoevenagel Reaction

Metal–organic frameworks for catalysis: the Knoevenagel reaction using zeolite imidazolate framework ZIF-9 as an efficient heterogeneous catalyst

A highly porous metal-organic framework (MOF-5) was synthesized by a solvothermal method, and used as an efficient heterogeneous acid catalyst for Friedel–Crafts alkylation reactions. The solid acid catalyst was characterized using a variety of different techniques, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), atomic absorption spectrophotometry (AAS), and nitrogen physisorption measurements. Quantitative conversion was achieved under mild conditions without the need for an inert atmosphere. The MOF-5 catalyst could be facilely separated from the reaction mixture, and could be reused several times without significant degradation in catalytic activity. Furthermore, no contribution from homogeneous catalysis of active acid species leaching into reaction solution was detected.

MOF-5 as an efficient heterogeneous catalyst for Friedel–Crafts alkylation reactions

A Zeolite Imidazolate Framework ZIF-8 Catalyst for Friedel-Crafts Acylation

A highly porous metal–organic framework (IRMOF-8) was synthesized by a solvothermal method, and used as an efficient heterogeneous catalyst for the Friedel–Crafts acylation reaction The solid catalyst was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), atomic absorption spectrophotometry (AAS), and nitrogen physisorption measurements High conversions were achieved in the presence of a catalytic amount of the IRMOF-8 (1–5 mol%) without the need for an inert atmosphere The solid catalyst could be facilely separated from the reaction mixture by simple centrifugation, and could be reused without a significant degradation in catalytic activity No contribution from homogeneous catalysis of active acid species leaching into the reaction solution was detected

Ky K. A. Le

Papers

Expanding Applications of Metal−Organic Frameworks: Zeolite Imidazolate Framework ZIF-8 as an Efficient Heterogeneous Catalyst for the Knoevenagel Reaction

Metal–organic frameworks for catalysis: the Knoevenagel reaction using zeolite imidazolate framework ZIF-9 as an efficient heterogeneous catalyst

MOF-5 as an efficient heterogeneous catalyst for Friedel–Crafts alkylation reactions

A Zeolite Imidazolate Framework ZIF-8 Catalyst for Friedel-Crafts Acylation

Towards applications of metal–organic frameworks in catalysis: Friedel–Crafts acylation reaction over IRMOF-8 as an efficient heterogeneous catalyst