Copper nanoparticles catalysed an efficient one-pot multicomponents synthesis of chromenes derivatives and its antibacterial activity

Abstract

In this study, copper nanoparticles (Cu NPs) were synthesised by using diethylenetriamine as a protective agent in chemical reduction method. The obtained nanoparticles were characterised by various spectroscopic techniques like powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), UVÀvisible spectroscopy, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal analysis (TG/DTA). The structure and composition were estimated by PXRD, FTIR, EDS, UVÀvisible and TG/DTA techniques, while particles size and morphology behaviours were investigated by SEM and TEM instrumentation. A noteworthy, average particle size of nanoparticles was found around 40 nm with spherical shapes. Furthermore, the applications part of NPs were studied as a catalyst for one-pot solvent-free green synthesis of 3,4-dihydropyrano[c] chromenes from different aromatic aldehydes, malonitrile and 4-hydroxycoumarin by stirring at 80 C. Moreover, the antibacterial properties of NPs were assessed in vitro against human bacterial pathogen such as Staphylococcus aureus, Escherichia coli, Klebsiella sp. and Pseudomonas aruginosa using agar well diffusion method. Gram positive bacteria S. aureus (18 mm) exhibited a maximum zone of inhibition at 60 mg/ml of Cu NPs. Nonetheless, antibacterial activities of Cu NPs (10À100 mg) were compared with four wellknown antibiotics likes amikacin (30 mcg), ciprofloxacin (5 mcg), gentamicin (5 mcg) and norfloxacin (10 mcg). This study indicates that Cu NPs exhibited a strong antibacterial activity against all the test pathogens even at lower concentration.

Fabrication of monodispersed copper oxide nanoparticles with potential application as antimicrobial agents

“…Although clinical application of copper oxide nanoparticles is controversial due to potential adverse effects to human cells, several studies reported less or no toxicity of copper oxide nanoparticles 59,70 . Unfortunately, the dependence of efficient bactericidal activity of Cu 2 O NPs up on the dissolved Cu +1 ions and solubility of www.nature.com/scientificreports/ the nanoparticles at lower pH significantly decreases their potential clinical applications at physiological pHs (6)(7)(8). Albeit, it is not the scope of the current study several studies have been conducted to exploit the enhanced antibacterial activity of copper oxide nanoparticles through readily releasing biocidal concentrations of copper ions at physiological pHs through synthesis of ligand modified copper oxo-hydroxide nanoparticles 71,72 .…”

“…In recent efforts to address this challenge, metallic and metallic oxide nanoparticles have emerged as significant and novel antimicrobial agents [5][6][7][8][9] . Nanoparticles exhibit fascinating mechanical, magnetic, electrical and optical properties as well as high adsorption and catalytic competencies compared to their bulk counterparts owing to their nanodimensions (1-100 nm range) 1,[10][11][12] .…”

Palladium and Copper: Advantageous Nanocatalysts for Multi-Step Transformations

“…Juneja and co-workers prepared CuNPs stabilized by diethylenetriamine by reduction of copper salts using hydrazine hydrate as a reducing agent [ 207 ]. Under solvent-free conditions, 40 nm Cu(0)NPs afforded chromenes derivatives (10 examples, 89–94% isolated yields) via three-component coupling of aldehyde, malonitrile and 4-hydroxychroman-2-one.…”

Graphene-based Materials and their Nanocomposites with Metal Oxides: Biosynthesis, Electrochemical, Photocatalytic and Antimicrobial Applications

“…Related research communities have turned their attention towards the study of new catalysts. Moreover, wide range of metal/metal oxide/polymers nanoparticles are investigated for their catalytic performance especially in organic transformation [142][143][144][145][146][147][148][149]. Excellent review exist on the photocatalytic applications of graphene metal oxide [150][151][152].…”