Ionic-liquid and cuprous sulfite containing halloysite nanoclay: An efficient catalyst for Click reaction as well as N- and O-arylations

Abstract

Using halloysite nanoclay (Hal) as a support and its multi-functionalization, a novel heterogeneous catalyst, Hal-IMI-SO3Cu, containing ionic liquid, copper species and sulfur trioxide was prepared and fully characterized by applying SEM/EDS, TEM, BET, ICP-AES, TGA, XRD and FTIR spectroscopy. Hal-IMI-SO3Cu exhibited excellent catalytic activity for the synthesis of triazoles through Click reaction of sodium azide, α-haloketones, alkyl halides and terminal alkynes as well as N-arylation and O-arylation of imidazole and phenol with aryl halides under mild and eco-friendly condition. The comparison of the catalytic activities of Hal-Cu, Hal-IMI-Cu (the catalyst without sulfur), Hal-SO3HCu (the catalyst without IL), Hal-IMI-SCu (the catalyst in which-SH was not oxidized to-SO3H) and Hal-IMI-SO3H (the catalyst without copper) with that of the catalyst for the Click reaction confirmed that copper played the dominant role in the catalysis. Moreover, the contribution of IL, and sulfur species to the catalysis was confirmed. It was also proved that the presence of

A Photoinduced Multicomponent Regioselective Synthesis of 1,4,5‐Trisubstituted‐1,2,3‐Triazoles: Transition Metal‐, Azide‐ and Oxidant‐Free Protocol

“…[15] Several methods have been investigated for the generation of 1,2,3triazoles with the help of metal triflates, organocatalysts, ionic liquids, bases etc. [16][17][18][19][20] Majority of these protocols employed heavy metals (Cu, Ru, Pd and Ir) which obstruct their use in environmental and biological concerns because of their toxicity and hazardous nature. [21][22][23][24] In order to overcome these, Ramachary, Bressy and Wang have developed metalfree enamine or enolate based organocatalytic azideketone [3 + 2] cycloaddition reaction, which now prospers as Ramachary-Bressy-Wang's [3 + 2] cycloaddition.…”

“…Later, the copper catalyzed azide‐alkyne cycloaddition reaction (CuAAC) discovered by Sharpless and Meldal has led to the most prominent strategy in 1,2,3‐triazole chemistry due to their excellent regioselectivity [15] . Several methods have been investigated for the generation of 1,2,3‐triazoles with the help of metal triflates, organocatalysts, ionic liquids, bases etc [16–20] . Majority of these protocols employed heavy metals (Cu, Ru, Pd and Ir) which obstruct their use in environmental and biological concerns because of their toxicity and hazardous nature [21–24] .…”

Biochar-Based Graphitic Carbon Nitride Adorned with Ionic Liquid Containing Acidic Polymer: A Versatile, Non-Metallic Catalyst for Acid Catalyzed Reaction

“…Similarly, various organic and inorganic anions can be incorporated in the structure of ILs to prepare task specific ILs [ 1 , 4 , 5 ]. The importance of ILs is due to their outstanding properties, such as high electric conductivity, low cost and thermal stability [ 6 , 7 , 8 ]. These features ascertained broad utility of ILs in various research sectors, including catalysis.…”

Pd on magnetic hybrid of halloysite and POSS‐containing copolymer: An efficient catalyst for dye reduction

“…In the pursuit of our inquiries on the chemistry and usage of Hal, [ 14,32–37 ] herein, we wish to describe synthesis and application of a new magnetic composite of Hal and polymer for catalytic dye degradation. The target composite was covalent and fabricated through reaction of vinyl‐functionalized magnetic Hal with hydroxyethyl methacrylate (HEMA) and methacrylate polyhedral oligomeric silsesquioxane (POSS).…”