Sustainable and Versatile CuO/GNS Nanocatalyst for Highly Efficient Base Free Coupling Reactions

Abstract

A CuO nanoparticles (CuO NPs)/graphene nanosheet (GNS) hybrid was prepared by a very simple method and employed as a nanocatalyst (CuO/GNS) for base free coupling reactions, namely, A3-coupling and aza-Michael reactions. TEM shows that CuO NPs of below ∼35 nm size are homogeneously dispersed on the GNS. Strong adhesion between CuO NPs and GNS was acknowledged by a high Raman I D/I G ratio and XPS result. The BET surface area of CuO/GNS was found to be 66.26 m2 g–1. The EDS and XPS investigations revealed that the weight percentage and chemical state of Cu in CuO/GNS were 4.46% and +2, respectively. Under mild reaction conditions, CuO/GNS exhibited an outstanding catalytic activity in terms of yield, turnover number (TON) and turnover frequency (TOF) toward A3-coupling reaction. A small amount of catalyst (10 mg, 0.7 mol % of Cu) is enough to carry out the reactions with a wide range of substrates. The CuO/GNS is stable, heterogeneous in nature and reusable for at least five times without any significant loses of yield. N-oxidation of tertiary amines was also carried out to explore further the activity of CuO/GNS, and the results are found to be excellent. Versatility of the CuO/GNS was realized from the superior catalytic activity of used CuO/GNS in aza-Michael reaction. Finally, GNS (∼95%) and CuO (as CuCl2) were successfully recovered from the used CuO/GNS and confirmed by TEM, Raman, XPS, XRD and SEM-EDS analyses.

Synthesis of Copper Oxide/Graphite Composite for High‐Performance Rechargeable Battery Anode

“…The positive G-band shift (about1 5cm À1 )i ndicates the presence of covalent bonding between the graphite surface and Cu oxide nanoparticles (CuÀ C). [32] The increased intensity of the Db ands can be calculated as the intensity ratio (I D /I G )o ft he Da nd Gb ands, and is an expression of the level of disorder in the graphite. The intensity ratios of graphite, GCuO 1:4, and GCuO 1:16 were0 .13, 0.66, and 0.74, respectively.I ncreases in the I D /I G ratio are generally the result of increased exposureo ft he edge planesa nd mis-alignedA Bs tacking in graphite.…”

A Novel Recyclable Ni/Cu/Fe Termetallic Nanocatalyst for the Synthesis of Propargylamines through the A3‐Coupling Reactions

“…Complete experimental section including materials, apparatus and details of the synthesis procedures are described in the Supporting Information. [56] Au 0 -P 3 S 3 nanocomposite Toluene/110/-3/94 3 [57] Ag-graphene nanocomposite CH 2 Cl 2 /60/-24/86 4 [58] CuO/graphene nanosheet C 2 H 3 N/82/-5/89 5 [59] Fe…”

Carbon‐Support‐Based Heterogeneous Nanocatalysts: Synthesis and Applications in Organic Reactions

“…Gopiraman et al. reported a CuO‐graphene hybrid catalyst (CuO‐GNS) by using CuO nanoparticles and graphene sheets (GNS) . Schematic illustration for the preparation of CuO/GNS hybrid catalyst is presented in Figure .…”