Nagaraj Basavegowda

Green fabrication of ferromagnetic Fe3O4 nanoparticles and their novel catalytic applications for the synthesis of biologically interesting benzoxazinone and benzthioxazinone derivatives

This paper demonstrates a novel and green approach for the synthesis of Fe3O4 nanoparticles using the leaf extract of Artemisia annua (A. annua), which is widely distributed in Asia as a medicinal plant. The formation of Fe3O4 nanoparticles was observed by UV-Vis spectroscopy. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared (FT-IR) spectroscopy, vibrating sample magnetometry (VSM), and thermogravimetric analysis (TGA). TEM analysis of Fe3O4 nanoparticles showed that they were spherical in shape with an average size of 6 nm. The synthesized Fe3O4 nanoparticles were used as a catalyst for the preparation of biologically interesting benzoxazinone and benzthioxazinone derivatives in high yields. These results showed that the synthesized Fe3O4 nanoparticles could be used as a catalyst in organic synthesis.

Preparation of Au and Ag nanoparticles using Artemisia annua and their in vitro antibacterial and tyrosinase inhibitory activities

This work describes a plant-mediated approach to the preparation of metal nanoparticles using leaf extract of Artemisia annua (A. annua), an ethno-medicinal plant widely found in Asia, which was used as reducing and stabilizing agent. A. annua is used in traditional Chinese medicine to alleviate fever. Au and Ag nanoparticles were prepared using a one-step aqueous method at room temperature without any toxic chemicals. The formation of Au and Ag nanoparticles was monitored by UV-vis spectroscopy. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). TEM analysis of Au nanoparticles showed that they had triangular and spherical shapes with sizes ranging from 15 to 40 nm. The silver nanoparticles were predominantly spherical and uniformly sized (30-50 nm). The Au and Ag nanoparticles produced showed significant tyrosinase inhibitory and antibacterial effects. These results suggest that the synthesized nanoparticles provide good alternatives in varied medical and industrial applications.

Ultrasonic-assisted green synthesis of palladium nanoparticles and their nanocatalytic application in multicomponent reaction

This paper describes a novel one pot synthesis of palladium nanoparticles (PdNPs) using a green method. An aqueous extract of Perilla frutescens leaf was used as a bioreductant to reduce Pd2+ ions to Pd0 without any extra surfactants or capping agents. Polyphenols and flavonoids are believed to be actively involved in the reduction process. The formation of PdNPs was confirmed by UV-Vis spectra. Transmission electron microscopy revealed spherical nanoparticles, ranging in size between 10 and 17 nm (average ∼13 nm). X-ray diffraction revealed reflections from the (111), (200), (220), (311) and (222) planes confirming the crystallinity of the nanoparticles with a face centred cubic (fcc) structure. Energy dispersive X-ray spectroscopy confirmed the presence of palladium. Fourier transform infrared spectroscopy suggested the role of polyols present in the P. frutescens leaf extract. The synthesized nanoparticles were used as catalysts for the synthesis of pyrazolylphosphonate derivatives in high yield. The excellent catalytic performance of the synthesized PdNPs can be associated with their extremely small size and high dispersity, so the synthesized PdNPs will be applicable for future industrial processes.

Sonochemically synthesized ferromagnetic Fe3O4 nanoparticles as a recyclable catalyst for the preparation of pyrrolo[3,4-c]quinoline-1,3-dione derivatives

This paper reports the green, rapid synthesis of Fe3O4 nanoparticles by the ultrasonic irradiation of Fe2O3 solution and Perilla frutescens (P. frutescens) leaf extract, which was used as both reducing and capping agent. The synthesized Fe3O4 nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis, vibrating sample magnetometry, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The FT-IR spectra indicated that the bioactive molecules present in the plant extract contain polyols, which act as a reducing as well as capping agent, as confirmed by TGA. TEM and SEM showed that the Fe3O4 nanoparticles were approximately spherical in shape with a mean size of 50 nm. The synthesized Fe3O4 nanoparticles exhibited ferromagnetic behavior with a saturation magnetization of 25.15 emu g−1. The Fe3O4 nanoparticles, with their easy recovery by an external magnetic field, exhibited strong catalytic activity towards pyrrolo[3,4-c]quinoline-1,3-dione derivatives. These results suggest that the Fe3O4 nanoparticles produced can be applied as a catalyst in organic synthesis and recycled at least five times without significant loss in its activity.

Biosynthesis of Fe, Pd, and Fe–Pd bimetallic nanoparticles and their application as recyclable catalysts for [3 + 2] cycloaddition reaction: a comparative approach

The surface adjustment of iron nanoparticles by secondary metals increases the reaction efficiency of bimetallic nanoparticles. This paper reports a green and facile approach for the synthesis of Fe, Pd and Fe–Pd bimetallic nanoparticles using an aqueous bark extract of Ulmus davidiana and their application as magnetically recoverable catalysts for the [3 + 2] cycloaddition of 1,4-naphthoquinones or benzoquinones with β-ketoamides. The surface chemistry of the Fe–Pd bimetallic nanoparticles was determined by X-ray photoelectron spectroscopy. The morphology, size, crystallinity, weight loss, oxidation state, and ferromagnetic behavior of the synthesized nanoparticles were investigated. The bimetallic nanoparticles exhibited strong catalytic activity in high yield for the synthesis of naphtho[1,2-b]furan-3-carboxamides and benzofuran-3-carboxamides compared to their respective monometallic nanoparticles. The nanocatalyst was recovered easily using an external magnetic field and recycled five times without significant loss in activity.

Sonochemical Green Synthesis of Yttrium Oxide (Y 2 O 3 ) Nanoparticles as a Novel Heterogeneous Catalyst for the Construction of Biologically Interesting 1,3-Thiazolidin-4-ones

This paper describes a facile and green strategy for the synthesis of yttrium oxide nanoparticles (Y2O3 NPs) by a straightforward process using Liriope platyphylla rhizome extract as the reducing agent and yttrium nitrate hexahydrate as the sole precursor without other additives. The crystallinity, surface chemistry, morphology, elemental composition, and thermal properties of the synthesized NPs are thoroughly investigated. The synthesized NPs shows remarkable catalytic activity for the construction of biologically interesting 1,3-thiazolidin-4-ones.Graphical Abstract

Access to enhanced catalytic core–shell CuO–Pd nanoparticles for the organic transformations

This paper describes the biosynthesis of core–shell CuO–Pd nanoparticles with the aid of a Cyperus rotundus rhizome extract. The crystallinity, surface chemistry, morphology and thermal properties of the synthesized nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and thermogravimetric analysis. The nanoparticles with Pd covered by a CuO enriched shell showed enhanced catalytic performance for organic transformations to synthesize 2,3-dihydroquinazolin-4(1H)-ones, spirooxindoles, and chromenylpyrimidin-2,4-diones in excellent yield. Moreover, the nanocatalyst can be recycled effectively for five consecutive reactions without significant loss of catalytic activity.

Efficient \hbox {Cu(OTf)}_{2}-catalyzed synthesis of novel and diverse 2,3-dihydroquinazolin-4(1H)-ones

An efficient one-pot synthesis of various 2,3-dihydroquinazolin-

Synthesis of silver nanoparticles using Satsuma mandarin (Citrus unshiu) peel extract: A novel approach towards waste utilization

4(1H)