CuSO4 nanoparticles loaded on carboxymethylcelulose/polyaniline composites: A highly efficient catalyst with enhanced catalytic activity in the synthesis of propargylamines, benzofurans, and 1,2,3‐triazoles

• Published in: Applied organometallic chemistry Vol. 35; no. 10
• Main Authors: Xu, Zhian, Xu, Jinxi, Li, Yiqun
• Format: Journal Article
• Language: English
• Published: 01.10.2021
• Subjects: A3 reactions; carboxymethylcellulose; CuAAC reactions; CuSO4 nanoparticles; polyaniline
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.6349

A novel and efficient heterogeneous CuSO4 nanoparticles (CuSO4 NPs) immobilized on carboxymethylcellulose/polyaniline (CuSO4NPs@CMC/PANI) composites were prepared via one‐pot and one‐step interfacial oxidative polymerization of aniline with sodium carboxymethylcellulose (CMC) as soft template and CuSO4 as catalyst. The in situ formed CuSO4 NPs were dispersed uniformly and firmly on the resultant composites and stabilized by complexation with hydroxyl groups (─OH), carboxylate groups (─COO−), nitrogen atoms, and delocalized π‐π conjugate benzenoid and quinoid moieties of CMC/PANI composites. The morphology, composition, and structure of the as‐fabricated composites were systematically characterized by X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and derivative thermogravimetry (DTG) techniques. The CuSO4NPs@CMC/PANI composites were successfully applied as catalysts in aldehyde‐alkyne‐amine (A3) coupling reactions, A3‐cycloisomerization tandem reactions, and Cu‐catalyzed azide‐alkyne cycloaddition (CuAAC) reactions. All reactions proceeded smoothly and afforded the desired products in excellent yields. Moreover, no significant decrease in catalytic ability was observed in A3 model reaction after 15 recycles, indicating CuSO4NPs@CMC/PANI composites exhibited easy separability and high reusability. Tolerance of wide scope of substrate, excellent catalytic activity, easy operation, recycling of catalyst, and environmental benign are the salient features of these catalytic process. CuSO4NPs@CMC/PANI composites were prepared in situ by oxidative polymerization of aniline with CMC─Na as soft template and CuSO4 as catalyst. The as‐formed CuSO4 nanoparticles grown simultaneously on the resultant CMC/PANI composites were stabilized by complexation with hydroxyl groups (─OH), carboxylate groups (─COO−), nitrogen atoms, and delocalized π‐π conjugate benzenoid and quinoid moieties of CMC/PANI composites. The CuSO4NPs@CMC/PANI composites showed superior catalytic activity for A3 coupling reactions, A3‐cycloisomerization tandem reactions, and CuAAC reactions.