Catalyst For A3-coupling Reaction Research Articles

A novel nanomagnetic palladium (II) complex of bisimidazolium-based N[sbnd]heterocyclic carbene; An efficient heterogeneous catalyst for A3 coupling reactions

Herein, a novel nanomagnetic NHC-Palladium complex was successfully prepared applying post-synthetic modification (PSM) condensation between Fe3O4-support imidazole and a synthetic bisamide moiety, carrying the alkyl halide functionalities at the end of its chain, followed by chelation of Pd ions to generate the corresponding complex. The [Fe3O4@bisimidazolium-Pd]2Cl− complex gave the best catalytic performance in synthesizing propargylamines through A3 coupling of various substituted aromatic and cycloaliphatic aldehydes and secondary amines with aromatic and liner alkynes in PEG-400. Primary amines are inefficient to produce unknown byproducts; whereas, secondary amines react quickly. Significantly, alkynes having a high electron density reduce the conversion rate. Moreover, aromatic and aliphatic aldehydes are active, but the electron-drawing substituent on benzaldehyde decreases the rate of conversion. Furthermore, the [Fe3O4@bisimidazolium-Pd]2Cl− catalyst can be reused seven times without metal leaching or losing its ability, which shows how stable it is when used in a reaction.

DABCO-based ionic liquid-modified magnetic nanoparticles supported gold as an efficient catalyst for A3 coupling reaction in water

In this work, a new heterogeneous catalyst, comprising gold supported on DABCO-triazole ionic liquid-modified magnetic nanoparticles (Fe3O4@DT-Au), is developed for A3-coupling reaction. This nano-catalyst is characterized using different techniques, such as TEM, SEM, SEM-elemental mapping, XRD, XPS, and TGA. Using a 0.05 mol% of this catalyst, the three-component reaction of amines, aldehydes and alkynes is efficiently performed at 40 °C in water. This catalyst is easily recovered and recycled through external magnetic forces for six times with a small decrease in the activity and re-used catalyst was characterized.

Synthesis of a magnetic-based yolk-shell nano-reactor: A new class of monofunctional catalyst by Cu0-nanoparticles and its application as a highly effective and green catalyst for A3 coupling reaction

A novel and yolk/shell nanoreactor catalyst (H-Fe3O4@h-Cu0@m-SiO2) was designed and synthesized with a hollow magnetite core encapsulated in a mesoporous silica shell which Cu0-nanoparticles were decorated in the interior cavity shell in order to enhance the catalytic activity. The morphology, structure and physicochemical properties of the yolk/shell nanoreactor were then fully characterized by using high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction patterns (XRD), Fourier transform infrared spectroscopy (FT-IR). The N2 absorption-desorption isotherms indicate a Brunauer–Emmett–Teller (BET) specific surface area of 287.36 m2/g and a pore width of 2–50 nm. Applied as a catalyst for three-component A3 coupling reaction of alkynes, aldehydes and amines under the optimized condition. Interestingly, the characterization results indicate that (H-Fe3O4@h-Cu0@m-SiO2) has great catalytic performance, which could be related to unique hollow morphology with an active core contains Cu0-nanoparticles, protective mesoporous shell and hollow void. This aspect of morphology leads to favoring the transfer of the reactants and products. Reusability up to 10 times without any obvious decline in catalytic activity and short reaction time are other advantageous of this green nano-reactor.

Copper nanoparticles supported on starch micro particles as a degradable heterogeneous catalyst for three-component coupling synthesis of propargylamines

Starch supported Cu NPs as a degradable heterogeneous catalyst for A3 coupling reaction.

Aldehyde–alkyne–amine (A3) coupling catalyzed by a highly efficient dicopper complex

A dicopper(i) complex was developed as highly efficient catalyst for A3 coupling reactions, which led to the formation of propargylamines.