PVP-Stabilized Copper Nanoparticles:  A Reusable Catalyst for “Click” Reaction between Terminal Alkynes and Azides in Nonaqueous Solvents

Abstract

Highly stable poly(N-vinyl-2-pyrrolidone) (PVP) protected copper nanoparticles were prepared using a simple chemical reduction route in different solvents {N, N-dimethyl formamide (DMF) and formamide (FA)} under aerated condition. The particles were characterized using TEM, SEM, XRD, and UV−visible spectroscopic techniques. Copper nanostructures of varying shapes and sizes were obtained using hydrazine hydrate as the reducing agent in both DMF and FA. However, reducing by ascorbic acid in FA leads to formation of mostly spherical copper nanoparticles with a narrow size distribution. The Cu nanoparticles serve as effective catalyst for 1,3-dipolar cycloaddition reactions between terminal alkynes and azides to synthesize 1,2,3-triazoles in excellent yields under mild reaction conditions. The nanocatalysts can be recycled and reused several times without significant loss of their catalytic activity.

Metal-based Inkjet Inks for Printed Electronics

“…The most frequently used is poly(N-vinyl-2-pyrrolidone) (PVP) of various molecular weights, which exhibits a highly effective protective function in both organic and aqueous media. PVP has been shown to be an effective stabilizer of aqueous dispersions of Ag and Cu NPs [67,79,[93][94][95][100][101][102][103][104][105][106][107][108] as well as an effective stabilizer of Ag and Cu NPs in organic solvents [69,101,109] and especially in polyol synthesis [61,77,78,110]. The polyol method, while using PVP as a stabilizer, was utilized in the preparation of Ag and Cu NPs (size range of 40-50 nm) as precursors of metal-based conductive inks [111][112][113][114][115].…”

New routes to Cu(i)/Cu nanocatalysts for the multicomponent click synthesis of 1,2,3-triazoles

“…In spite of this, processing costs and the search for new combinations of benecial properties have led to continued interest in the replacement of established noble metal nanocatalysts with those of relatively inexpensive metals. 12 In this vein, nanoparticulate copper has recently been deployed in various chemical syntheses, this having been enabled by the development of routes to the preparation of the copper-based nanomaterials Cu(0), [13][14][15][16] CuO and Cu 2 O. 17,18 As a result, copper nanoparticles (Cu NPs) have found many applications in, amongst other reactions, the reduction of functional groups, 19 the formation of carbon-carbon and carbon-nitrogen bonds, 20 and in so-called "click" chemistry.…”

Copper nanoparticle heterogeneous catalytic ‘click’ cycloaddition confirmed by single-molecule spectroscopy

“…There is an interest in improving efficiency, reducing cost as well as byproducts, and discovering new catalysts 5,[7][8][9][10][11][12] for this powerful conjugation tool. Copper nanoparticles (CuNP) are being explored as click catalysts in the hope of improving reusability and efficiency compared to their solution counterparts [13][14][15][16][17][18][19][20][21] . Despite recent proof-of-concept examples of CuNP-catalysed click reactions, few investigate the catalytic activity of CuNP, and generally it is difficult, if not impossible, to establish if the true catalyst is the CuNP, copper ions leaching from it 22 , or if the CuNP acts as a reductant converting Cu(II) to Cu(I).…”