Functionalized Polystyrene Supported Copper(I) Complex as an Effective and Reusable Catalyst for Propargylamines Synthesis in Aqueous Medium

MCM-41 supported 2-aminothiophenol/Cu complex as a sustainable nanocatalyst for Suzuki coupling reaction

We have developed an innovative mesoporous nanocatalyst by carefully attaching a 2-aminothiophenol-Cu complex onto functionalized MCM-41. This straightforward synthesis process has yielded a versatile nanocatalyst known for its outstanding efficiency, recyclability, and enhanced stability. The structural integrity of the nanocatalyst was comprehensively analyzed using an array of techniques, including BET (Brunauer-Emmett-Teller) for surface area measurement, ICP (Inductively Coupled Plasma) for metal content determination, EDS (Energy-Dispersive X-ray Spectroscopy) for elemental mapping, XRD (X-ray Diffraction) for crystalline structure elucidation, SEM (Scanning Electron Microscopy), EMA (Elemental Mapping Analysis), TEM (Transmission Electron Microscopy), TGA (Thermogravimetric Analysis), FT-IR (Fourier Transform Infrared Spectroscopy), AFM (Atomic Force Microscopy), and CV (cyclic voltammetry). Subsequently, the catalytic properties of the newly developed MCM-41-CPTEO-2-aminothiophenol-Cu catalyst was evaluated in the synthesis of biphenyls, demonstrating outstanding yields through a Suzuki coupling reaction between phenylboronic acid and aryl halides. Importantly, this reaction was conducted in an environmentally friendly medium. Note the remarkable recyclability of the catalyst, proving its sustainability over six cycles with minimal loss in activity additionally hot filtration test was prepared to examine the stability of this nanocatalyst. This outstanding feature emphasizes the catalyst's potential for long-term, environmentally conscious catalytic applications.

Constructing a metal-free 2D covalent organic framework for visible-light-driven photocatalytic reduction of CO2: a sustainable strategy for atmospheric CO2 utilization

A 2D polyimide-linked covalent organic framework (COF) with band gap energy of 2.2 eV is developed as a stable and efficient porous photocatalyst which shows CO2 reduction to formic acid, formaldehyde and methanol.

Visible-light-driven sustainable conversion of carbon dioxide to methanol using a metal-free covalent organic framework as a recyclable photocatalyst

A 2D covalent organic framework (COF) was synthesized by copolymerization between 4,4′-biphenyldicarbaldehyde and 1,3,5-tris-(4-aminophenyl) triazine (TAPT). This COF exhibited excellent photocatalytic performance for the CO2 reduction to methanol.

A sustainable pseudo-homogeneous catalyst from renewable biomass: design, development and catalytic applications

Pseudo-homogeneity, sustainability and functional growth in a sustainable raw material derived catalyst.

α-Tertiary Propargylamine Synthesis via KA2-Type Coupling Reactions under Solvent-Free CuI-Zeolite Catalysis

The potential of copper(I)-zeolite catalysis was evaluated in the three-component KA²-coupling mediated synthesis of α-tertiary propargylamines. Our archetypal copper(I)-doped zeolite Cu^I-USY proved to be efficient under ligand- and solvent-free conditions at 80 °C. Usable up to four times, this catalytic material enables the coupling of diverse ketones, alkynes, and amines with a broad functional group tolerance. A decarboxylative and a desilylative version, respectively, involving an alkynoic acid and trimethylsilylacetylene as alkyne surrogates, was also set up to bypass selectivity issues and/or to access α-tertiary propargylamines that are unattainable under standard KA² conditions. Interestingly, the KA²-type coupling reactions were successfully linked to other Cu^I-catalyzed reactions, thus resulting in sequential one-pot processes under full Cu^I-USY catalysis.

Polymer Beads Decorated with Dendritic Systems as Supports for A3 Coupling Catalysts

Abstract

The gel type microscopic polymer beads bearing epoxy functionalities were modified using the two-stage procedures in order to decorate their surface with the moieties of the zeroth order PAMAM type dendrimer and different heterocyclic aldehydes (2-pyridinecarboxaldehyde, 2-pyrrolidinecarboxaldehyde, furfural or 2-thiophenecarboxaldehyde). The polymeric supports provided in this manner were then used for the immobilization of copper(II) ions. The resulting materials were characterized using different instrumental techniques (optical microscopy, SEM, FTIR microscopy, DR UV–Vis, ICP-OES, and thermal analysis). They were also used as catalysts in the model A3 coupling reaction of benzaldehyde, morpholine and phenylacetylene. The best catalytic activity was found for the polymeric catalyst bearing 2-pyridinecarboxaldehyde moieties. It turned out to be effective in the A3 coupling reactions included different benzaldehyde, alkyne, and secondary amine derivatives, as well. It could also be recycled several times without a significant decrease in its activity in the model A3 coupling reaction.

Graphic Abstract

In Situ Immobilized Silver Nanoparticles on Rubia tinctorum Extract-Coated Ultrasmall Iron Oxide Nanoparticles: An Efficient Nanocatalyst with Magnetic Recyclability for Synthesis of Propargylamines by A3 Coupling Reaction

This research suggests a green method for synthesizing hybrid magnetic nanocomposites that can be used as a reductant and a stabilizing agent for immobilizing metal nanoparticles (NPs). The central idea is the modification of magnetic NPs using Rubia tinctorum extract, which consists of numerous carbonyl and phenolic hydroxyl functional groups to increase adsorption of metals and chelate silver ions, and decrease the adsorption of silver ions by Ag NPs, in situ. Thus, the suggested catalyst preparation process does not require toxic reagents, additional reductants, and intricate instruments. To show the effectiveness of the plant extract in reducing and immobilizing Ag NPs, the structural, morphological, and physicochemical features of the particles are studied using Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, vibrating sample magnetometry, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. One of the advantages of the suggested method is to reduce the size of the magnetic NPs from 15-20 to 2-5 nm, in the presence of the extract. Additionally, the prepared Fe3O4@R. tinctorum/Ag nanocatalyst is demonstrated to exhibit a very high activity in the catalysis of the three-component reaction of aldehydes, amines, and alkynes (A3 coupling) with good to high yields of diverse propargylamines. Moreover, the nanocatalyst can be recovered several times with no considerable leaching or loss of performance.

Green synthesis of Au nanoparticles using an aqueous extract ofStachys lavandulifoliaand their catalytic performance for alkyne/aldehyde/amine A3coupling reactions

High reaction rate and easy availability make green synthesis of metal nanoparticles noticeable.

Solventless, selective and catalytic oxidation of primary, secondary and benzylic alcohols by a Merrifield resin supported molybdenum(vi) complex with H2O2 as an oxidant

Here, we have described the synthesis, characterization and catalytic activity of a dioxo-molybdenum(vi) complex supported on functionalized Merrifield resin (MR-SB-Mo). The functionalization of Merrifield resin (MR) was achieved in two-steps viz. carbonylation (MR-C) and Schiff base formation (MR-SB). The compounds, MR-C, MR-SB and MR-SB-Mo, were characterized at each step of the synthesis by elemental, SEM, EDX, thermal, BET and different spectroscopic analysis. The catalyst, MR-SB-Mo, efficiently and selectively oxidized a wide variety of alcohols to aldehydes or ketones using 30% H₂O₂ as an oxidant with reasonably good TOF (660 h⁻¹ in case of benzyl alcohol). The catalyst acted heterogeneously under solventless reaction conditions and did not lead to over oxidized products under optimized conditions. The catalyst afforded regeneration and can be reused for at least five reaction cycles without loss of efficiency and product selectivity. A reaction mechanism for the catalytic activity of MR-SB-Mo was proposed and a probable reactive intermediate species isolated.

Synthesis of a Merrifield resin supported dioxomolybdenum(vi) complex. The compound was well characterized and it catalysed the oxidation of alcohols to aldehydes or ketones with high TOF.

Recent Advances in C-C and C-N Bond Forming Reactions Catalysed by Polystyrene-Supported Copper Complexes

This present mini-review covers recently published results on Cu(I) and Cu(II) complexes immobilized on polystyrene carriers, which are used as heterogeneous, eco-friendly reusable catalysts applied for carbon-carbon and carbon-nitrogen forming reactions. Recent advances and trends in this area are demonstrated in the examples of oxidative homocoupling of terminal alkynes, the synthesis of propargylamines, nitroaldolization reactions, azide alkyne cycloaddition, N-arylation of nitrogen containing compounds, aza-Michael additions, asymmetric Friedel-Crafts reactions, asymmetric Mukaiyama aldol reactions, and asymmetric 1,3-dipolar cycloaddition of azomethine ylides. The type of polystyrene matrix used for the immobilization of complexes is discussed in this paper, and particularly, the efficiency of the catalysts from the point of view of the overall reaction yield, and possible enantioselectivity and potential reusing, is reviewed.

Copper(ii) incorporated functionalized polystyrene catalyzed N-arylation of amides under solvent free condition with broad substrate scope

A new polymer supported Cu(ii) catalyst has been reported for N-arylation of various amides with aryl halides under neat reaction conditions.