Multicomponent click reaction catalyzed by organic surfactant-free copper sulfide (sf-CuS) nano/micro flowers

Single-step synthesis of ternary metal chalcogenides (sf-CuInS2 and sf-CuInSe2) stripped off the organic cover and their use as a catalyst for symmetric Glaser-Hay coupling reactions

Generally, inorganic nano/microparticles produced by chemical routes are covered by organic surfactants or polymers to control their agglomeration during their synthesis. However, these surfactants and polymers negatively affect their catalytic activity because these molecules mask the surface. This work presents the synthesis of surfactant-free CuInS2 and CuInSe2 (sf-CuInS2 and sf-CuInSe2) nano/microparticles through simple reactions without surfactant or polymer coatings using LiBH4 under a thermodynamically favourable condition. These reactions are rare observations of a single-step process to produce ternary metal chalcogenides without any template assistance. We have also demonstrated efficient catalysis by sf-CuInS2 nanoparticles in the coupling reaction of substituted phenylacetylenes. We tested it as catalysts in dimerizing 1,3-diyne derivatives while using 8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the base. These Glassar-Hay coupling reactions are conducted at room temperature in acetonitrile (4-7 h, depending on the substrate) using 10 mg of sf-CuInS2. The maximum yield obtained in these reactions is 97%, while the catalyst is reusable for five cycles with little difference in its ability to catalyse. The effectiveness of the catalyst is credited to the availability of a free catalytic surface.

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.

Nanomagnetic macrocyclic Schiff-base-Mn(ii) complex: an efficient heterogeneous catalyst for click approach synthesis of novel β-substitued-1,2,3-triazoles

In the present work, a novel symmetrical 15-membered macrocyclic Schiff base complex of manganese was prepared using the reaction of the synthetic 2,6-diacetylpyridine functionalized Fe₃O₄ MNPs with 2,2-(piperazine-1,4-diyl)dianiline and Mn(ii) bromide salt via a template approach. The resulting [Fe₃O₄@PAM-Schiff-base-Mn][ClO₄] heterogenized complex was characterized using FT-IR, XRD, BET, TGA, EDX, Xray-mapping, SEM, TEM and VSM analysis. To demonstrate proof of concept, Huisgen 1,3-dipolar cycloaddition synthesis of 1,2,3-triazoles was selected to evaluate the activity and reusability of the catalyst. The ethanol as a green solvent proved to be an excellent reaction medium for this synthesis. Yields of up to 100% were obtained in some cases. Significantly, as demonstrated, [Fe₃O₄@PAM-Schiff-base-Mn][ClO₄] catalyst was recycled for 8 cycles without losing catalytic activity under the optimized reaction conditions. The hot filtration and ICP-OES tests ratified that there was no leaching of metal during the catalytic reaction, indicating the heterogeneous manner of the catalyst.

Recent developments and perspectives in the copper-catalyzed multicomponent synthesis of heterocycles

Heterocyclic compounds have become an inevitable part of organic chemistry due to their ubiquitous presence in bioactive compounds. Copper-catalyzed multicomponent synthesis of heterocycles has developed as the most convenient and facile synthetic route towards complex heterocyclic motifs. In this review, we discuss the advancements in the field of copper-catalyzed multicomponent reactions for the preparation of heterocycles since 2018.

Heterocycles are abundant in several pharmaceutical and naturally occurring compounds. Copper-catalyzed multicomponent reactions are a convenient method for easy access to heterocycles. In this review, we focus on the advancement in this field for the past two years.