Copper(I) Confined in Interlayer Space of Montmorillonite: A Highly Efficient and Recyclable Catalyst for Click Reaction

Copper Dispersed Covalent Organic Framework for Azide-Alkyne Cycloaddition and Fast Synthesis of Rufinamide in Water

A crystalline porous bipyridine-based Bpy-COF with a high BET surface area (1864 m2 g-1) and uniform mesopore (4.0 nm) is successfully synthesized from 1,3,5-tris-(4'-formyl-biphenyl-4-yl)triazine and 5,5'-diamino-2,2'-bipyridine via a solvothermal method. After Cu(I)-loading, the resultant Cu(I)-Bpy-COF remained the ordered porous structure with evenly distributed Cu(I) ions at a single-atom level. Using Cu(I)-Bpy-COF as a heterogeneous catalyst, high conversions for cycloaddition reactions are achieved within a short time (40 min) at 25 °C in water medium. Moreover, Cu(I)-Bpy-COF proves to be applicable for aromatic and aliphatic azides and alkynes bearing various substituents such as ester, hydroxyl, amido, pyridyl, thienyl, bulky triphenylamine, fluorine, and trifluoromethyl groups. The high conversions remain almost constant after five cycles. Additionally, the antiepileptic drug (rufinamide) is successfully prepared by a simple one-step reaction using Cu(I)-Bpy-COF, proving its practical feasibility for pharmaceutical synthesis.

Recent Advances in Copper-Based Solid Heterogeneous Catalysts for Azide-Alkyne Cycloaddition Reactions

The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction is considered to be the most representative ligation process within the context of the "click chemistry" concept. This CuAAC reaction, which yields compounds containing a 1,2,3-triazole core, has become relevant in the construction of biologically complex systems, bioconjugation strategies, and supramolecular and material sciences. Although many CuAAC reactions are performed under homogenous conditions, heterogenous copper-based catalytic systems are gaining exponential interest, relying on the easy removal, recovery, and reusability of catalytically copper species. The present review covers the most recently developed copper-containing heterogenous solid catalytic systems that use solid inorganic/organic hybrid supports, and which have been used in promoting CuAAC reactions. Due to the demand for 1,2,3-triazoles as non-classical bioisosteres and as framework-based drugs, the CuAAC reaction promoted by solid heterogenous catalysts has greatly improved the recovery and removal of copper species, usually by simple filtration. In so doing, the solving of the toxicity issue regarding copper particles in compounds of biological interest has been achieved. This protocol is also expected to produce a practical chemical process for accessing such compounds on an industrial scale.

Investigation of halloysite nanotubes and Schiff base combination with deposited copper iodide nanoparticles as a novel heterogeneous catalytic system

The design, preparation and characterization of a novel composite based on functionalization of halloysite nanoclay with Schiff base followed by immobilization of copper iodide as nanoparticles is revealed. This novel nano composite was fully characterized by utilization of FTIR, SEM/EDX, TGA, XRD and BET techniques. This Cu(I) NPs immobilized onto halloysite was successfully examined as a heterogeneous, thus easily recoverable and reusable catalyst in one of classist organic name reaction so-called “Click Reaction”. That comprised a three component reaction of phenylacetylene, α-haloketone or alkyl halide and sodium azide in aqueous media to furnish 1,2,3‐triazoles in short reaction time and high yields. Remarkably, the examination of the reusability of the catalyst confirmed that the catalyst could be reused at least six reaction runs without appreciable loss of its catalytic activity.

Effect of Copper and Titanium-Exchanged Montmorillonite Nanostructures on the Packaging Performance of Chitosan/Poly-Vinyl-Alcohol-Based Active Packaging Nanocomposite Films

In this study, CuMt and TiMt montmorillonites were produced via an ion-exchange process with Cu⁺ and Ti⁴⁺ ions. These nanostructured materials were characterized with X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR) measurements and added as nanoreinforcements and active agents in chitosan (CS)/poly-vinyl-alcohol (PVOH)-based packaging films. The developed films were characterized by XRD and FTIR measurements. The antimicrobial, tensile, and oxygen/water-barrier measurements for the evaluation of the packaging performance were carried out to the obtained CS/PVOH/CuMt and CS/PVOH/TiMt films. The results of this study indicated that CS/PVOH/CuMt film is a stronger intercalated nanocomposite structure compared to the CS/PVOH/TiMt film. This fact reflected higher tensile strength and water/oxygen-barrier properties. The antibacterial activity of these films was tested against four food pathogenic bacteria: Escherichia coli, Staphylococcus aureus, Salmonella enterica and Listeria monocytogenes. Results showed that in most cases, the antibacterial activity was generated by the CuMt and TiMt nanostructures. Thus, both CS/PVOH/CuMt and CS/PVOH/TiMt films are nanocomposite candidates with very good perspectives for future applications on food edible active packaging.

Montmorillonite clay-based heterogenous catalyst for the synthesis of nitrogen heterocycle organic moieties: a review

The use of montmorillonite clay as solid catalyst has grabbed much attention in the liquid phase reactions for organic synthesis. In recent years, there has been a lot of interest in organic synthesis using montmorillonite-based composites, especially in the synthesis of heterogeneous nanoparticles. Due to the robust and green nature of montmorillonite-based nanocatalysts, it has been widely used in N-heterocyclic reactions. In this review, we have concentrated on the reports pertaining the use of montmorillonite-based nanocatalyst in the synthesis of N-heterocycles, a category of organic compounds with excellent biological properties. This manuscript is arranged by the types of N-containing heterocycles synthesized using montmorillonite-based composite as catalysts including polycyclic spirooxindoles, heterocyclic propargylamine, indole-based heterocycles, quinoline and its derivatives, six-membered N-heterocyclic-based compounds and five-membered N-heterocyclic-based compounds. Special attention was given to the structural stability under experimental parameters of the montmorillonite-based composite with the incidence of metal leaching and reusability. Finally, along with recent developments, new findings in heterogeneous montmorillonite (Mt)-based catalysis have also been addressed.

Synthesis, characterization and in vitro anticancer activity of thiabendazole-derived 1,2,3-triazole derivatives

Thiabendazolium salts with 1,2,3-triazole motifs were synthesized and characterized; they exhibit good cytotoxic activity.

Ultrasound promoted facile one pot synthesis of triazole derivatives catalyzed by functionalized graphene oxide Cu(I) complex under mild conditions

A facile one pot three component reaction of alkyl halides, sodium azide with terminal alkynes can be catalyzed by functionalized graphene oxide copper (I) complex under ultrasonic irradiation at room temperature. In this protocol, the 1,4-disubstituted 1,2,3-triazoles were afforded as target pure products in excellent yields and short reaction times. The prepared catalyst has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), Energy Dispersive X-ray (EDX) and field emission scanning electron microscopy (FE-SEM) techniques. Also, the catalyst is chemoselective and stable and can be reused several times without any appreciable loss of its catalytic activity.

Recent Advances in Recoverable Systems for the Copper-Catalyzed Azide-Alkyne Cycloaddition Reaction (CuAAC)

The explosively-growing applications of the Cu-catalyzed Huisgen 1,3-dipolar cycloaddition reaction between organic azides and alkynes (CuAAC) have stimulated an impressive number of reports, in the last years, focusing on recoverable variants of the homogeneous or quasi-homogeneous catalysts. Recent advances in the field are reviewed, with particular emphasis on systems immobilized onto polymeric organic or inorganic supports.

Cu–Al mixed oxide catalysts for azide–alkyne 1,3-cycloaddition in ethanol–water

Cu(Al)O mixed oxide promotes the formation of 1,2,3-triazoles from an alkyne–azide cycloaddition reaction with excellent yields using an EtOH–H₂O mixture as the solvent under microwave heating.