Effect of pore sizes on catalytic activities of arenetricarbonyl metal complexes constructed within Zr-based MOFs

Partial-Interpenetration-Controlled UiO-Type Metal-Organic Framework and its Catalytic Activity

An unprecedented correlation between the catalytic activity of a Zr-based UiO-type metal-organic framework (MOF) and its degree of interpenetration (DOI) is reported. The DOI of an MOF is hard to control owing to the high-energy penalty required to construct a partially interpenetrated structure. Surprisingly, strong interactions between building blocks (inter-ligand hydrogen bonding) facilitate the formation of partially interpenetrated structures under carefully regulated synthesis conditions. Moreover, catalytic conversion rates for cyanosilylation and Knoevenagel condensation reactions are found to be proportional to the DOI of the MOF. Among MOFs with DOIs in the 0-100% range, that with a DOI of 87% is the most catalytically active. Framework interpenetration is known to lower catalytic performance by impeding reactant diffusion. A higher effective reactant concentration due to tight inclusion in the interpenetrated region is possibly responsible for this inverted result.

Isolating reactive metal-based species in Metal-Organic Frameworks - viable strategies and opportunities

Structural insight into reactive species can be achieved via strategies such as matrix isolation in frozen glasses, whereby species are kinetically trapped, or by confinement within the cavities of host molecules. More recently, Metal-Organic Frameworks (MOFs) have been used as molecular scaffolds to isolate reactive metal-based species within their ordered pore networks. These studies have uncovered new reactivity, allowed observation of novel metal-based complexes and clusters, and elucidated the nature of metal-centred reactions responsible for catalysis. This perspective considers strategies by which metal species can be introduced into MOFs and highlights some of the advantages and limitations of each approach. Furthermore, the growing body of work whereby reactive species can be isolated and structurally characterised within a MOF matrix will be reviewed, including discussion of salient examples and the provision of useful guidelines for the design of new systems. Novel approaches that facilitate detailed structural analysis of reactive chemical moieties are of considerable interest as the knowledge garnered underpins our understanding of reactivity and thus guides the synthesis of materials with unprecedented functionality.

Synergistic Effect over Sub-nm Pt Nanocluster@MOFs Significantly Boosts Photo-oxidation of N-alkyl(iso)quinolinium Salts

Quinolones and isoquinolones are of interest to pharmaceutical industry owing to their potent biological activities. Herein, we first encapsulated sub-nm Pt nanoclusters into Zr-porphyrin frameworks to afford an efficient photocatalyst Pt_0.9@PCN-221. This catalyst can dramatically promote electron-hole separation and ¹O₂ generation to achieve synergistic effect first in the metal-organic framework (MOF) system, leading to the highest activity in photosynthesis of (iso)quinolones in >90.0% yields without any electronic sacrificial agents. Impressively, Pt_0.9@PCN-221 was reused 10 times without loss of activity and can catalyze gram-scale synthesis of 1-methyl-5-nitroisoquinolinone at an activity of 175.8 g·g_cat⁻¹, 22 times higher than that of PCN-221. Systematic investigations reveal the contribution of synergistic effect of photogenerated electron, photogenerated hole, and ¹O₂ generation for efficient photo-oxidation, thus highlighting a new strategy to integrate multiple functional components into MOFs to synergistically catalyze complex photoreactions for exploring biologically active heterocyclic molecules.

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A state-of-the-art photocatalyst for preparation of bioactive (iso)quinolones

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Synergistic catalysis of photogenerated e⁻/h⁺ and ¹O₂

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Sub-nm Pt_0.9@PCN-221 with a high efficiency of e⁻-h⁺ separation and ¹O₂ generation

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.

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.

Immobilisation of a molecular epoxidation catalyst on UiO-66 and -67: the effect of pore size on catalyst activity and recycling

Amino-functionalised metal-organic frameworks UiO-66 and -67 were post-synthetically modified with salicylaldehyde. A molybdenum complex was immobilised on the resulting materials. They were characterised by (13)C-MAS-NMR, XPS and PXRD to confirm immobilisation and stability. The immobilised complex is an active and reusable catalyst for olefin epoxidation with tert-butyl hydroperoxide (TBHP) as an oxidant. It is shown that the effective pore size, probed with Brunauer-Emmett-Teller (BET) surface area analysis and the number of amino groups affect the diffusion of reactants and products, as well as catalyst recycling.

Zeolitic imidazolate frameworks as heterogeneous catalysts for a one-pot P–C bond formation reaction via Knoevenagel condensation and phospha-Michael addition

ZIF-8 promotes a sequential one-pot reaction efficiently to produce organophosphorus compounds via Knoevenagel condensation and phospha-Michael addition.

Solvent-induced synthesis of cobalt(ii) coordination polymers based on a rigid ligand and flexible carboxylic acid ligands: syntheses, structures and magnetic properties

The structural formations for compounds 1–5 are effected by using different solvents or different carboxylic acid ligands.

A mixed dicarboxylate strut approach to enhancing catalytic activity of a de novo urea derivative of metal-organic framework UiO-67

A hydrogen-bond donating MOF catalyst based on the framework, containing both urea-functionalized dicarboxylate and biphenyl-4,4'-dicarboxylate struts, was synthesized by a de novo route. The mixed strut framework has larger pore sizes and improved catalytic activity for Henry reactions than the pure strut analogue, which contains only the urea-functionalized dicarboxylate linker.