Search

Copper nanoparticles (Cu NPs) were synthesized via a green method by using of Plantago asiatica leaf extract as natural solvent and reaction biomedia under environmentally benign reaction conditions. It was observed that use of Plantago asiatica leaf extract makes a simple, eco-friendly and cost effective method for the preparation of the Cu NPs and can reduce copper ions into Cu(0) within 5min of reaction time without using any stabilizer or surfactant agent. The progress of the reaction was monitored using UV-Visible spectroscopy. Polyphenolics could be adsorbed on the surface of Cu NPs, possibly by interaction through π-electrons interaction in the absence of other strong ligating agents. The catalytic activity of the Cu NPs was evaluated by cyanation of aldehydes in the extract as a green solvent. This method provided several advantages such as cleaner easy work-up, shorter reaction time and higher yield. Cu NPs were characterized by FT-IR, UV-Vis, TEM, X-ray diffraction and the synthesized products were characterized by FT-IR and 1 H NMR., (Copyright © 2017 Elsevier Inc. All rights reserved.)

In this paper, a novel, efficient and green method for the preparation of Naringin sulfuric acid (NSA) as a Brønsted acid organocatalyst and silver nanoparticles (Ag NPs) by using Gongronema latifolium leaf extract as a reducing and stabilizing agent is introduced. The catalysts were characterized using the powder XRD, SEM, EDS, TEM, UV-Vis and FT-IR spectroscopy. Afterward, the catalytic activity of synthesized NSA and Ag NPs were investigated for the synthesis of N-monosubstituted ureas via the hydration of cyanamides in aqueous medium. All products were obtained in good to excellent yields. These methods provided several advantages such as shorter reaction time, simpler work-up and higher yield., (Copyright © 2017 Elsevier Inc. All rights reserved.)

In this work, the Ag/Fe 3 O 4 nanocomposite was prepared by Euphorbia peplus Linn (L.) leaf extract as a suitable reducing source and stabilizing agent. The green synthesized nanocomposite was characterized using X-ray diffraction analysis (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) images, energy-dispersive X-ray spectroscopy (EDS) and FT-IR spectroscopy. TEM analysis of Ag/Fe 3 O 4 nanocomposite showed the spherical shape nanoparticles (NPs) with an average size of 5-10nm. The Ag/Fe 3 O 4 nanocomposite then was used as a magnetically recoverable catalyst for the [2+3] cycloaddition of arylcyanamides and sodium azide in high yields and short reaction times without formation of hydrazoic acid (HN 3 ). Also it can be easily recovered via applying of external magnetic field and reused several times without significant loss of activity., (Copyright © 2017 Elsevier Inc. All rights reserved.)

In current research, Ag/RGO/Fe 3 O 4 nanocomposite was synthesized through applying the aqueous extract of Lotus garcinii leaves through a two-step method. The plant extract was utilized as agents for reduction and stabilization in biosynthesizing nanocomposite. The green synthesized nanocatalyst was characterized by FT-IR, FE-SEM, EDX, XRD, TEM, UV-Vis absorption spectroscopy. The catalytic activity of the biosynthesized nanocomposite was studied by reducing different colored solutions contained organic pollutants such as 4-nitrophenol (4-NP), Congo red (CR) and Rhodamine B (RhB). In order to verify commercial applications of the prepared heterogeneous nanocatalyst, reusability and recoverability tests were performed in five successive catalytic reactions., (Copyright © 2017 Elsevier Inc. All rights reserved.)

This work reports the green synthesis of the Cu/reduced graphene oxide/Fe 3 O 4 (Cu/RGO/Fe 3 O 4 ) nanocomposite as a new catalytic system for cyanation of aldehydes to nitriles. This nanocomposite catalytic system was synthesized by aqueous extract of leaves of Euphorbia bungei Boiss as a reducing and stabilizing agent. Various substituted aryl nitrile were prepared under optimized conditions and providing moderate to excellent yields. In this process the catalyst exhibited a strong magnet response and could be easily separated by an external magnet and reused with no loss of catalytic activity., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In this paper, we report the green synthesis of the Cu/Fe3O4 nanoparticles using Silybum marianum L. seeds extract and their application as magnetically separable nanocatalyst for the reduction of nitroarenes. Our method is clean, nontoxic and environment friendly. The synthesized nanocatalyst is characterized by XRD, TEM, EDS and UV-visible techniques. UV-visible spectroscopy is used to monitor the kinetics of the Cu/Fe3O4 nanoparticles formation. The results from Fourier transform infrared spectroscopy showed that the C=O and C-O groups in the plant seeds extract played a critical role in capping the nanoparticles. The expected reaction mechanism in the formation of nanoparticles is also reported. The catalyst is recoverable by magnetic decantation and could be reused several times without significant loss in catalytic activity., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Pd nanoparticles (NPs) were synthesized by using aqueous extract of leaves of Euphorbia thymifolia L., a non-toxic ecofriendly material. The catalytic activity of the Pd NPs was investigated in the cyanation of aryl iodides using K4Fe(CN)6 as the cyanating agent under ligand-free conditions. The nitriles were obtained in good to excellent yield and the catalyst can be recovered and reused for five times without significant loss of catalytic activity., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In this study, copper nanoparticles (Cu NPs) were synthesized using a rapid, single step and completely green biosynthetic method by reduction of CuCl2 · 2H2O solution with aqueous extract of leaves of Otostegia persica containing flavonoid and other phenolics as a main factor which acts as reducing agent and efficient stabilizer. UV-vis spectra gave surface plasmon resonance (SPR) at 560 nm. The Cu NPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). A possible synthesis mechanism of Cu NPs was presented. In addition, we investigated the catalytic activity of Cu NPs for the one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles under mild reaction conditions with good to excellent yields. The catalyst could be easily recovered by centrifugation and reused at least five recycles with no significant decreases in the yields., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Through this manuscript the green synthesis of palladium nanoparticles supported on reduced graphene oxide (Pd NPs/RGO) under the mild conditions through reduction of the graphene oxide and Pd(2+) ions using barberry fruit extract as reducing and stabilizing agent is reported. The as-prepared Pd NPs/RGO was characterized by UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The Pd NPs/RGO could be used as an efficient and heterogeneous catalyst for reduction of nitroarenes using sodium borohydride in an environmental friendly medium. Excellent yields of products were obtained with a wide range of substrates and the catalyst was recycled multiple times without any significant loss of its catalytic activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Copper oxide (CuO) nanoparticles (NPs) were synthesized by biological method using aqueous extract of Thymus vulgaris L. leaves as a reducing and capping agent. The progress of the reaction was monitored using UV-visible spectroscopy. The advantages of this procedure are simple operation, use of cheap, natural, nontoxic and benign precursors, absence of toxic reagents and mild and environmentally friendly conditions. The green synthesized CuO NPs was characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). More importantly, the green synthesized CuO NPs was found to be an excellent heterogeneous catalyst for ligand-free N-arylation of indoles and amines. The N-arylated products were obtained in good to excellent yield and the catalyst can be recovered and reused for further catalytic reactions with almost no loss in activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A green synthesis process was developed for production of the Pd/TiO2 nanoparticles (NPs) without using toxic, hazardous and dangerous materials. Myrtus communis L. leaf extract serves as a mild, renewable and non-toxic reducing agent. The advantages of this biosynthesis method include use of cheap, clean, nontoxic and environmentally benign precursors and simple procedures without time-consuming polymerization and problems with treatment of a highly viscous polymeric resin. More importantly, the synthesized Pd/TiO2 NPs presented excellent catalytic activity for ligand-free Suzuki-Miyaura coupling which could be easily separated from the reaction mixture and reused many times with no loss of activity. Therefore, these properties indicate demonstrative benefits of the catalyst. The Pd/TiO2 NPs was characterized by FESEM, TEM, FT-IR, UV-vis spectroscopy and EDS., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A reduced graphene oxide (RGO)/Fe3O4 based nanocomposite with palladium nanoparticles (Pd NPs) has been synthesized via a green route by Withania coagulans leaf extract as a reducing and stabilizing agent and its catalytic activity has been tested for the reduction of 4-nitrophenol (4-NP) in water at room temperature. The hydroxyl groups of phenolics in W. coagulans leaf extract is directly responsible for the reduction of Pd(2+), Fe(3+) ions and GO. The nanocomposite was characterized by X-ray diffraction (XRD), fourier transformed infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), Vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). Furthermore, due to the magnetic separability and high stability of the composite the catalyst can be recovered and recycled several times without marked loss of activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

We describe a method for supporting palladium nanoparticles on magnetic nanoparticles using Euphorbia stracheyi Boiss root extract as the natural source of reducing and stabilizing agent. The progress of the reaction was monitored using UV-visible spectroscopy. The nanocatalyst was characterized by FE-SEM, TEM, XRD, EDS, FT-IR spectroscopy and ICP. The nanocatalyst was applied as an efficient, magnetically recoverable, highly reusable and heterogeneous catalyst for one-pot reductive amination of aldehydes at room temperature. The nanocatalyst was easily recovered by applying an external magnet and reused several times without considerable loss of activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

This work reports a facile and green synthesis of Ag/TiO2 nanocomposite by extract of leaves of Euphorbia heterophylla without any stabilizer or surfactant. The green synthesized Ag/TiO2 nanocomposite was characterized by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD) and UV-vis. The Ag/TiO2 nanocomposite was found to be effective catalyst for reduction of various dyes, such as 4-nitrophenol (4-NP), Methyl orange (MO), Congo red (CR) and Methylene blue (MB) in the presence of NaBH4 in water at room temperature. Catalysis reactions were monitored by employing UV-vis spectroscopy. Catalysis reactions followed pseudo-first order rate equation. The catalyst can be recovered and reused several times without significant loss of its catalytic activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

For the first time the extract of the plant of Euphorbia granulate was used to green synthesis of Pd nanoparticles (NPs) as a heterogeneous catalyst for the phosphine-free Suzuki-Miyaura coupling reaction at room temperature. This method is a facile and eco-friendly way in organic synthesis using the plant extract as biomedia, bioreductant and capping ligand which considerably stabilizes the surface of Pd NPs. The presence of flavonoid and phenolics acids in the extract could be responsible for the reduction of Pd(2+) ions and formation of the corresponding Pd NPs., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Zeolites, which are nontoxic, abundant, and cheap, are very promising supports for the design and preparation of new and environmentally benign catalysts. In this study, Cu nanoparticles (NPs) were immobilized on the surface of natural Natrolite zeolite by Anthemis xylopoda flowers aqueous extract as a reducing and stabilizing agent. Afterward, the catalytic performance of the prepared catalyst was investigated for N-formylation of amines at room temperature under environmentally benign reaction conditions. The catalyst could be reused at least 5 times without any decrease in activity. The advantages of the present protocol include the use of green catalyst, easy isolation of the products, reusability of catalyst, absence of nontoxic reagents, and excellent yield of the products., (Copyright © 2015 Elsevier Inc. All rights reserved.)

CuO nanoparticles (NPs) were prepared by Anthemis nobilis flowers extract as a reducing and stabilizing agent and employed in catalyzing an aldehyde-amine-alkyne coupling reaction. The synthesized CuO NPs was characterized by SEM, EDS, XRD, FT-IR and UV-visible techniques. A diverse range of propargylamines were obtained in a good to high yield. Furthermore, the separation and reuse of CuO NPs was very simple, effective and economical., (Copyright © 2015 Elsevier Inc. All rights reserved.)

During this study, we report the green synthesis of copper nanoparticles (Cu NPs) using Ginkgo biloba L. leaf extract as a reducing and stabilizing agent under surfactant-free conditions. The formation of Cu NPs is monitored by recording the UV-vis absorption spectra. The green synthesized Cu NPs are characterized by TEM, EDS, FT-IR and UV-visible techniques. According to UV-vis results, the synthesized Cu NPs by this method are quite stable even after one month indicating the stability of Cu NPs. In terms of environmental impact and economy, metallic Cu NPs offer several advantages over homogeneous and traditional heterogeneous catalysts. In addition, due to the increased metal surface area, Cu NPs shows very high catalytic activity for the Huisgen [3+2] cycloaddition of azides and alkynes at room temperature. Furthermore, the catalyst can be simply recovered and reused several times with almost no loss in activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A facile, efficient and environmentally-friendly protocol has been developed for the green synthesis of CuO nanoparticles (NPs) by aqueous extract of Gundelia tournefortii as a mild, renewable and non-toxic reducing agent. CuO NPs were characterized by SEM, TEM, XRD, EDS, FT-IR and UV-vis spectroscopy. More importantly, the green synthesized CuO NPs presented excellent catalytic activity for reduction of 4-nitrophenol and synthesis of N-monosubstituted ureas via hydration of cyanamides with the aid of acetaldoxime as an effective water surrogate in ethanol as a green solvent. The catalyst was easily separated and the recovered catalyst was reused many times without any significant loss of the catalytic activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

In this paper, we report the preparation of Natrolite zeolite supported copper nanoparticles as a heterogeneous catalyst for 1,3-diploar cycloaddition and synthesis aryl nitriles from aryl iodides under ligand-free conditions. The catalyst was characterized using XRD, SEM, TEM, EDS and TG-DTA. The experimental procedure is simple, the products are formed in high yields and the catalyst can be recycled and reused several times without any significant loss of catalytic activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

During this study, we report the green synthesis of silver nanoparticles (Ag NPs) using Euphorbia helioscopia Linn leaf extract for the synthesis of propargylamines. Also, the structural and optical properties are studied. The synthesized nanoparticles are characterized by TEM, XRD, FT-IR and UV-visible techniques. UV-visible studies show an absorption band at 440 nm due to surface plasmon resonance (SPR) of the silver nanoparticles. Furthermore, the catalyst exhibits high catalytic activity, superior cycling stability and excellent substrate applicability., (Copyright © 2015 Elsevier Inc. All rights reserved.)

We report the green synthesis of palladium/CuO nanoparticles (Pd/CuO NPs) using Theobroma cacao L. seeds extract and their catalytic activity for the reduction of 4-nitrophenol and Heck coupling reaction under aerobic conditions. The catalyst was characterized using the powder XRD, TEM, EDS, UV-vis and FT-IR. This method has the advantages of high yields, elimination of surfactant, ligand and homogeneous catalysts, simple methodology and easy work up. The catalyst can be recovered from the reaction mixture and reused several times without any significant loss of catalytic activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)