Aromatic N-Arylations Catalyzed by Copper-Anchored Porous Zinc-Based Metal-Organic Framework under Heterogeneous Conditions

Copper-Based Metal–Organic Frameworks (MOFs) as an Emerging Catalytic Framework for Click Chemistry

In the extensive terrain of catalytic procedures for the synthesis of organic molecules, metal–organic frameworks (MOFs) as heterogenous catalysts have been investigated in a variety of chemical processes, including Friedel–Crafts reactions, condensation reactions, oxidations, and coupling reactions, and utilized owing to their specific properties such as high porosity, tuneability, extraordinary catalytic activity, and recyclability. The eminent copper-tailored MOF materials can be exceptionally dynamic and regioselective catalysts for click reactions (1,3-dipolar cycloaddition reaction). Considering the fact that Cu(I)-catalyzed alkyne–azide cycloaddition (CuAAC) reactions can be catalyzed by several other copper catalysts such as Cu (II)-β-cyclodextrin, Cu(OAc)2, Fe3O4@SiO2, picolinimidoamide–Cu(II) complex, and Cu(II) porphyrin graphene, the properties of sorption and reusability, as well as the high density of copper-MOFs, open an efficient and robust pathway for regimented catalysis of this reaction. This review provides a comprehensive description and analysis of the relevant literature on the utilization of Cu-MOFs as catalysts for CuAAC ‘click’ reactions published in the past decade.

Multifunctional Catalysis by a One-Dimensional Copper(II) Metal Organic Framework Containing Pre-existing Coordinatively Unsaturated Sites: Intermolecular C-N, C-O, and C-S Cross-Coupling; Stereoselective Intramolecular C-N Coupling; and Aziridination Reactions

The coordinatively unsaturated sites (CUS) are vital in metal-centered catalysis. Metal-organic frameworks (MOFs) provide a unique opportunity to generate and stabilize CUS due to their robust structure. Generally, the generation of CUS in MOFs needs prior activation under heat and high vacuum to remove labile molecules occupying the catalytic sites. Herein, we report a solvothermal synthesis of a ready-to-use copper MOF containing accessible pre-existing CUS that does not need activation. The single crystal X-ray diffraction structure reveals a square planar Cu(II) center with two N-methylimidazoles (Mim) and one benzenedicarboxylic acid (BDC) with the formula unit [Cu^II(BDC)(Mim)₂]_n (Cu-1D) forming an infinite one-dimensional (1D) chain along the c axis. The 1D chains are stabilized by noncovalent π-π, CH···π, and H-bonding interaction to give 2D (sheet-like) and 3D networks in the solid state. The quantification of non-covalent interaction is studied by Hirshfeld surface analysis, and the formation of a higher architecture in the solid state is confirmed by SEM analysis. The reported Cu-1D MOF acts as a solid heterogeneous catalyst and exhibits efficient catalytic activity in intermolecular and intramolecular cross-coupling reactions. Intermolecular C-heteroatom cross-coupling of a variety of N-heterocycles, aliphatic, aromatic, alicyclic amines and amides (C-N), phenols (C-O), and thiols (C-S) with aryl halides (halide = I, Br) was achieved with 70 to 95% yield, better than the state-of-the-art Cu-based homogenous system. The C-N coupling catalytic cycle is initiated by the in situ reduction of Cu(II) by KOH/DMSO to Cu(I) species. Subsequently, Cu(I) undergoes oxidative addition followed by reductive elimination to form a cross-coupled product. High stereoselectivity was found for the intramolecular C-N coupling reaction to give tetrahydroquinoxalines with an enantiomeric excess (ee) of more than 99%. For a broader application, Cu-1D was applied as the catalyst for the synthesis of a library of aziridines that gives yields of up to 99% with more than 93% recyclability for each cycle.

Selective luminescent sensing of metal ions and nitroaromatics over a porous mixed-linker cadmium(ii) based metal–organic framework

A potential luminescent sensor based on porous metal organic framework for the detection of metal ions (Al3+, Fe3+ or Cr3+) and nitro-explosive, 2,4,6-tri-nitrophenol has been discovered. MOF is capable of detecting aqueous phase analyte through luminescent sensing.

A post-synthetically modified metal–organic framework for copper catalyzed denitrative C–N coupling of nitroarenes under heterogeneous conditions

Post-synthesis modification of DMOF, afforded a desired material for strategic infusion of catalytically active centers in a porous matrix. The catalyst is capable for denitrative C–N coupling reactions of nitroarenes under heterogeneous conditions.

Combined experimental and computational studies on preferential CO2 adsorption over a zinc-based porous framework solid

Synthesis, characterization and study of selective CO₂ adsorption over other small gas molecules on a Zn-based porous framework compound.

Engineering Metal-Organic Framework Catalysts for C-C and C-X Coupling Reactions: Advances in Reticular Approaches from 2014-2018

Metal-organic frameworks (MOFs) are a class of crystalline porous materials that have been actively used for several industrial and synthetic applications. MOFs are spatially and geometrically extrapolated coordination polymers with intriguing properties such as tunable porosity and dimensionality. In terms of their catalytic efficiency, MOFs combine the easy recoverability of heterogeneous catalysts with the increased selectivity of biological catalysts. It is therefore not surprising that a lot of work on optimizing MOF catalysts for organic transformations has been carried out over the past decade. In this review, recent developments in MOF catalysis are summarized, with special attention being paid to C-C, C-N, and C-O coupling reactions. The influence of pore size, pore environment, and load on catalytic activity is described. Post-synthetic stabilization techniques and host-guest interactions in caged MOF scaffolds are detailed. Mechanistic aspects pertaining to the use of MOFs in asymmetric heterogeneous catalysis are highlighted and categorized.

Copper(I)-USY as a Ligand-Free and Recyclable Catalyst for Ullmann-Type O-, N-, S-, and C-Arylation Reactions: Scope and Application to Total Synthesis

The copper(I)-doped zeolite Cu^I-USY proved to be a versatile, efficient, and recyclable catalyst for various Ullmann-type coupling reactions. Easy to prepare and cheap, this catalytic material enables the arylation and heteroarylation of diverse O-, N-, S-, and C-nucleophiles under ligand-free conditions while exhibiting large functional group compatibility. The facility of this catalyst to promote C-O bond formation was further demonstrated with the total synthesis of 3-methylobovatol, a naturally occurring diaryl ether of biological relevance. From a mechanistic viewpoint, two competitive pathways depending on the nature of the nucleophile and consistent with the obtained results have been proposed.

A carbon nitride supported copper nanoparticle composite: a heterogeneous catalyst for the N-arylation of hetero-aromatic compounds

Copper nanoparticle catalyzed N-arylation of hetero-aromatic molecules.

Synthesis of 1,2-Dicarbonyl-3-enes by Hydroacylation of 1-Alkynes with Glyoxal Derivatives Using Metal-Organic Framework Cu/MOF-74 as Heterogeneous Catalyst

A crystalline copper-based metal-organic framework Cu/MOF-74 was synthesized, and used as an efficient heterogeneous catalyst for the synthesis of 1,2-dicarbonyl-3-enes by means of the hydroacylation of 1-alkynes with glyoxal derivatives in the presence of a base. Cu/MOF-74 was found to be more catalytically active for the synthesis of 1,2-dicarbonyl-3-enes than other MOFs including Cu₂ (BDC)₂ (DABCO), Cu₃ (BTC)₂ , Cu(BDC), Cu₂ (NDC)₂ (DABCO), Cu₄ I₄ (DABCO)₂ , Ni-MOF-74, Zn-MOF-74, Fe₃ O(BDC)₃ , In(OH)(BDC), and Zr₆ O₄ (OH)₄ (BDC)₆ . Cu/MOF-74 also exhibited better performance than other homogeneous copper catalysts, including Cu(OAc)₂ , Cu(NO₃ )₂ , CuI, CuBr, CuCl, CuCl₂ , and CuBr₂ . The Cu/MOF catalyst was able to be recovered and reused several times without a significant degradation in catalytic activity. To the best of our knowledge, the formation of 1,2-dicarbonyl-3-enes has not previously been carried out under heterogeneous catalysis conditions.

Synthesis of imidazo[1,5-a]pyridines via oxidative amination of the C(sp3)–H bond under air using metal–organic framework Cu-MOF-74 as an efficient heterogeneous catalyst

1,3-Diarylated imidazo[1,5-a]pyridines were synthesized via oxidative amination of the C(sp³)–H bond using Cu-MOF-74 as an efficient heterogeneous catalyst.

Application of iron-based metal–organic frameworks in catalysis: oxidant-promoted formation of coumarins using Fe3O(BPDC)3 as an efficient heterogeneous catalyst

An iron-based metal–organic framework Fe₃O(BPDC)₃ was used as an efficient heterogeneous catalyst for the synthesis of coumarins.

Heterogeneous O-arylation of nitroarenes with substituted phenols over a copper immobilized mesoporous silica catalyst

Highly efficient heterogeneous mesoporous silica based Cu-catalyst has been designed forO-arylation of phenol using nitroarene to afford unsymmetrical diarylethers. It can be recycled up to 5 times without any significant loss of catalytic activity.

Crystal engineering, structure–function relationships, and the future of metal–organic frameworks

After twenty years of vigorous R&D, where are MOFs headed?

Cu(0)@Al2O3/SiO2 NPs: an efficient reusable catalyst for the cross coupling reactions of aryl chlorides with amines and anilines

The C–N cross coupling reaction of aryl chlorides with various alkyl/aryl amines catalyzed by copper nanoparticles impregnated on alumina/silica support (Cu(0)@Al₂O₃/SiO₂) was investigated and the catalyst showed excellent reactivity and efficacy.

A family of ligand and anion dependent structurally diverse Cu(ii) Schiff-base complexes and their catalytic efficacy in an O-arylation reaction in ethanolic media

Catalytic O-arylation reactions have been studied by employing a variety of copper(ii) Schiff-base complexes under environmentally benign conditions.