Synthesis and Characterization of Cucurbit[6]uril Supported Copper Oxide Nanoparticles, CuO@CB[6]: Application as Nanocatalyst for the Synthesis of 2H‐indazoles. Issue 35 (17th September 2019)

• Record Type: Journal Article
• Authors: Verma, Shruti; Kujur, Shelly; Agrahari, Bhumika; Layek, Samaresh; Pathak, Devendra D.
• Is Part Of: ChemistrySelect. Volume 4:Issue 35(2019)
• Page Start: 10408
• Page End: 10416
• Publication Date: 2019-09-17
• Subjects: copper nanoparticles -- cucurbit[6]uril -- heterogeneous catalyst -- 2H-indazoles; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201902957
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Fine nanoparticles of CuO, generated in‐situ by the chemical reduction method, were immobilized on cucurbit[6]uril support to afford nanocomposite CuO@CB[6] as an air‐stable green powder. The nanocomposite was fully characterized by various physicochemical techniques, such as FTIR, PXRD, XPS, FESEM, EDX, Elemental mapping, HRTEM, TGA, and ICP‐AES. It has been found to be an efficient heterogeneous nanocatalyst for the synthesis of a series of 2 H ‐indazoles from aldehyde, amine, and azide, under base‐ and ligand‐free conditions, at a low concentration of the metal (0.2 mole %). The augmented catalytic activity of the CuO NPs is attributed to the fine size of the nanoparticles. The nanocatalyst was retrieved from the reaction mixture by simple filtration and reused up to five times with insignificant deprivation in its catalytic activity. All synthesized 2 H ‐indazoles were isolated in good to excellent yield (55‐96%) and characterized by 1 H and 13 C NMR studies. Three new indazoles are additionally characterized by DEPT 135 spectroscopy and HRMS spectra. Abstract : Fine CuO NPs of size 3–5 nm were immobilized on a Cucurbit[6]uril and characterized by physicochemical techniques. The nanocomposite CuO@CB[6] was found to be an efficient catalyst for the synthesis of a series of 2 H ‐indazoles in good to excellent yields. The nanocatalyst could be easily recovered and reused up to five times without significant loss in the catalytic activity.