Oxides of copper have been investigated for decades due to their unique semiconductor and optical properties. The review of literature revealed that very few reports are available on the synthesis of copper oxide nanoparticles using microorganisms and plant extracts. In this paper, we have reported the synthesis of copper oxide nanoparticles (CuO) using tea leaf and coffee powder extracts under microwave irradiations. The synthesis was carried out by irradiating metal salt and the extracts of tea and coffee in 1:3 ratio in a microwave at 540 W for 7-8 min. The synthesized nanoparticles were characterized by Scanning electron microscope, X-ray diffraction, UVvisible spectroscopy and Fourier transform infrared spectroscopy. The antibacterial activity of these nanoparticles was tested against six human pathogenic microbes. It was interesting to find that these nanoparticles possess remarkable antibacterial activity against two human pathogenic bacteria. Moreover, the use of environmentally benign materials for the synthesis of CuO nanoparticles offers numerous benefits of eco-friendliness and compatibility for pharmaceutical and other biomedical applications.
Graphene quantum dots (GQDs) as a new series of nanomaterials have drawn great attention in recent years owning to their unique properties. Here we report the single-step synthesis of GQDs using pyrolysis of citric acid which produced GQDs at different pH. The effect of different pH was studied in detail to optimize the conditions of the formation of GQDs. UV-Visible absorption and normalized fluorescence spectra were applied to analyze the optical properties of GQDs. The particle size distribution of the GQDs in case of varying pH was determined to optimize the synthesis conditions. The surface morphology and microstructures were studied by atomic force microscope (AFM).
With an increasing awareness of green and clean energy, zinc oxide-based solar cells were found to be suitable candidates for cost-effective and environmentally friendly energy conversion devices. In this paper, we have reported the green synthesis of zinc oxide nanoparticles (ZnONPs) by thermal method and under microwave irradiation using the aqueous extract of tomatoes as non-toxic and ecofriendly reducing material. The synthesised ZnONPs were characterised by UVÀvisible spectroscopy (UVÀvis), infra-red spectroscopy, particle size analyser, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction study (XRD). A series of ZnO nanocomposites with titanium dioxide nanoparticles (TiO 2 ) and graphene oxide (GO) were prepared for photovoltaic application. Structural and morphological studies of these nanocomposites were carried out using UVÀvis, SEM, XRD and AFM. The currentÀvoltage measurements of the nanocomposites demonstrated enhanced power conversion efficiency of 6.18% in case of ZnO/GO/ TiO 2 nanocomposite.
Indole derivativesIndole derivatives R 0140 Microwave Induced Diastereoselective Synthesis of Spiro[indole-oxiranes] and Their Conversion to Spiro[indole-pyrazoles]. -Stereoselectivity of the title reaction depends on reaction time and power output, allowing for the selective synthesis of the (3RS, 3'SR) isomer (II) or the (3RS, 3'RS) isomer (IV). Results on antifungal and antitubercular activities are presented. -(DANDIA*, A.; SINGH, R.; SAHA, M.; SHIVPURI, A.; Pharmazie 57 (2002) 9, 602-605; Dep. Chem., Univ. Rajasthan,
Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under nitrogen atmosphere. Purification with concentrated nitric acid introduced approximately 0.1 mol/g of carboxylic acid groups as found by acid-base titrimetric analysis. XRD pattern showed the 0.15 mol/g basic graphitic structure of these nano carbon materials. Their SEM and TEM images revealed cube or brick shaped nano crystals. These nanocrystals are further characterized by FT-IR, Raman, and EDAX analysis. High density wrapping of carboxylated acid groups introduces surface passivation of these nano carbon cubes and nano carbon bricks exhibiting photoluminescence. Solid state electronic spectrum showed several bands in the ultraviolet and visible region and excitation at 336 and 474 nm generates photoluminescence respectively in the ultraviolet and visible region.
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