JOURNAL OF NANOSTRUCTURE IN CHEMISTRY
Year:2014 | Volume:4 | Issue:1|Papers Count:11

Sulfonic acid-functionalized ordered nanoporous Na+ -montmorillonite, as a newly reported solid acid nanocatalyst, was efficiently used for the tetrahydropyranylation and detetrahydropyranylation of alcohols and phenols. All reactions were performed at room temperature in high to excellent yields. Ease of preparation and handling of the catalyst, heterogeneous reaction conditions, easy work-up of the products, high reaction rates and reusability of the catalyst are the main advantages of this method.

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, UV-visible 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.

Nanoclusters of nickel sulphide (NiS)n and iron sulphide (FeS)n for n=3–5 are studied using B3LYP exchange correlation function with 6-31G as a basis set.The structural stability of different isomers of NiS and FeS is analysed with the optimized energy, binding energy and vibrational studies. The electronic properties of isomers are discussed in terms of HOMO–LUMO gap, ionization potential, electron affinity, and embedding energy of different clusters. Based on the calculated energy, planar ring, linear ladder and bipyramidal cube of NiS and FeS nanoclusters are found to be more stable. The increase in number of atoms in the clusters leads to increase in its stability. The dipole moment is high for planar rhombus and linear ladder structures of NiS and FeS nanoclusters.The ionization potential and electron affinity are high for planar ring structure of NiS and FeS clusters. The value of energy gap of linear ladder NiS nanocluster and cube and bipyramidal cube structures of FeS is found to be low. The binding energy for cube structure of NiS and FeS clusters is found to be high. Hexagonal ring structure of NiS and FeS clusters has low embedding energy value. The other parameters such as dipole moment and point symmetry are also discussed. The structural stability and electronic properties will provide an insight for experimentalist to tailor new materials that have potential importance in engineering applications.

A nonenzymatic cholesterol biosensor was fabricated at the surface of carbon nanotube electrode (CCNT), obtained from coconut oil. The voltammetric behavior of cholesterol at CCNT electrode was investigated by cyclic voltammetry and differential pulse voltammetry in the presence of 0.001 M H2SO4 as electrolyte.The influence of the experimental parameters on the peak currents of cholesterol like pH, accumulation time, and scan rates were optimized. Under optimum conditions, the peak current was found to be linear in the cholesterol concentration range from 1 to 50lM with a sensitivity of ~15.31 ± 0.01 mA mM-1 cm-2 and response time of about 6 s. Some characteristic studies of the nonenzymatic biosensor, such as reproducibility, substrate specificity, and storage stability have also been studied.

In this study, tin-doped indium oxide (ITO) thin films were produced by the sol-gel spin-coating technique with an inexpensive salt of indium (In (NO3) 3-H2O) and SnCl4 as indium and tin precursors (the molar ratio of In: Sn was 9: 1), respectively. Then the prepared thin films were annealed in the temperature of 550oC under argon atmosphere (the pressure of 10 torr). Polyvinylalcohol (PVA) was used as stabilizers in the synthesis of ITO sol. The prepared ITO thin films were characterized by EDX, XRD, FT-IR, UV-Vis spectroscopy and SEM images.The XRD patterns of the thin films indicated the main peak of the (2 2 2) plane corresponded to indium oxide with high degree of crystallinity. The FT-IR spectroscopy confirmed that indium tin oxide has been prepared by appearance of a peak at 470 cm-1 that can be assigned to the vibrations of In–O bonds. The optical direct band gap of ITO thin films was calculated about 3.98-4.17 eV by optical transmittance measurements. The grain size of ITO nanoparticles was obtained at about 25–50 nm by SEM images. The electrical characterization was done by the four-point probe method to determine the sheet resistance and resistivity. The effects of coating number on ITO thin films properties were investigated. The low resistivity (sheet resistance of 2.5 kX/cm2) and highly transparent films were obtained that can be applied as covers on heater windows. Appearance of a peak at 470 cm-1 can be assigned to the vibrations of In–O bonds and are characteristic of cubic In2O3.

This work reports an ecofriendly approach for the synthesis of Ruthenium nanoparticles (Ru NPs) using aqueous leaf extract ofGloriosa superba. G. superba contains cholidonic, superbine, colchicine, gloriosol, phytosterils and stigmasterin, which are found to be responsible for the bio-reduction of Ru NPs. The synthesized Ru NPs were characterized using UV–Vis spectroscopy, Fluorescence spectra, FTIR, XRD, SEM and EDX analyses.UV–Vis spectra of the aqueous medium containing Ru NPs showed a gradual decrease of the absorbance peak observed at 494 nm. Fluorescence spectra of Ru NPs emission (kem) exhibited at 464 nm are attributed to the Ru=Np bonds transition. The biomolecules responsible for the reduction of Ru NPs were analyzed by FTIR. XRD results confirmed the presence of Ru NPs with hexagonal crystal structure. The calculated crystallite sizes using Scherrer formula are in the range from 25 to 90 nm.Scanning electron microscopy ascertained spherical nature of the Ru NPs. The EDX analysis showed the complete elemental composition of the synthesized Ru NPs. The synthesized Ru NPs exhibited good antibacterial performance against gram-positive and gram-negative bacterial strains, which was studied using standard disc diffusion method. The synthesis of Ru NPs by this method is rapid, facile and can be used for various applications.

Biosynthesis of green nanomaterials and their characterization comprise an emerging field of nanotechnology, due to their wide range of applications. The present study deals with the synthesis of silver nanoparticles (AgNPs) using an aqueous leaf extract ofCassia alata. The AgNPs are characterized using UV-Visible spectroscopy.The surface plasmon resonance spectrum of AgNPs was obtained at 434 nm, and scanning electron microscopy coupled with X-ray energy dispersive spectroscopy (EDX) data revealed that AgNPs were uniformly spherical in shape. EDX data show very strong silver signal and weak signals to other elements, and X-ray diffraction patterns reveal that the particles are crystalline in nature with facecentered cubic structure. Fourier transform-infrared spectroscopy reveals that the carbonyl group (C=O, 1637.07 cm-1) is involved in the reduction of Ag+ to Ag.The synthesized AgNPs were crystalline in nature and spherical in shape, with an average of[41 nm size. The stability of AgNPs is due to its high negative zeta potential, which is –50.7 mV. Further, atomic force microscopy studies also revealed that the average particle size was47 nm which correlates with the above result of particle size analysis. The present study also indicates that AgNPs have considerable antibacterial activity and exceptionally superior antifungal activity, in comparison with standard antimicrobial drugs.

Zeolite-sepiolite inorganic nanoheterostructures have been hydrothermally synthesized by adding a dispersion of colloidal sepiolite to a solution able to produce a nanocrystalline zeolite (silicalite). The obtained product could be recovered in good yield by simple filtration only when the relative sepiolite concentration exceeded a threshold of 1.8 wt% in the synthesis mixture (amounting to 1: 3 sepiolite: zeolite wt. ratio in the recovered product). The resulting heterostructures were characterized by XRD, FTIR, thermal (TG-DTA) and chemical analyses, N2 adsorption, TEM, SEM, 29Si NMR, and methylene blue adsorption. The intimate zeolite-sepiolite interaction at the surface produced a good dispersion of zeolite particles and prevented their sintering upon calcination to remove the organic structure-directing agent.Experiments in conditions yielding microcrystalline silicalite support the idea that the sepiolite surface acts as nucleation sites for the zeolite crystallization. The textural properties of the nanozeolite-sepiolite heterostructure are not a linear combination of their components’.

A novel Cu-TiO2/chitosan hybrid thin film was successfully prepared without any heat treatment process by sol-gel method on a polycarbonate substrate. Based on the photocatalytic activity and adsorption property of the entire thin film, a simple, reliable, reproducible and inexpensive method was developed for the removal of some heavy metals from aquatic media. The removal process of Pb2+ and Cr6+ was performed by flotation of coated polycarbonate substrate in the bulk of sample for a definite time in absence and presence of light. The effect of influential parameters in removal process, including thin film surface area, removal time, sample volume and pH was investigated and variation in selected ion concentrations was monitored using a graphite furnace-atomic absorption spectrometer. Considering the optimized conditions, effect of interference ions was studied and according relative standard deviation amounts, no evidence of interference was observed. The proposed method showed good reproducibility in a way that the amounts of relative standard deviation percentage values (n=10) for Pb2+ and Cr6.were obtained 4.303 and 3.865, respectively. The whole procedure showed to be conveniently applicable and quite easy to manipulate.

Carbon nanotubes as potential material for drug delivery can pass through cell walls, transfer, and liberate drugs in particular tissues. The goal of this article is to survey the insertion of an anticancer drug called Tretinoin into CNT (10, 7) and CNT (8, 5). All computations are surveyed by molecular dynamics simulation in various temperatures (270 and 310 K) and in water solution and ethanol co-solvent.0.2 M ethanol is studied that is more than normal range of blood alcohol content. The molecular dynamic simulation results show that the insertion of Tretinoin into the carbon nanotube in a water solute environment could be related to the diameter of the nanotube and in the flow of the waters via hydrophilic interactions.Insertion of drug into a CNT (10, 7) is observed in the presence of water at 310 K and ethanol inhibits encapsulation.The results of structure parameters and free energy of interaction indicate that the energy of nanotube and Tretinoin decreases after the encapsulation in water, and increases in ethanol co-solvent. The results also show that by increasing initial temperature, heat capacity increases.

Semiclassical Monte Carlo simulation is used to determine the effect of microscopic ripples on spin relaxation length in freely suspended single-layer graphene.Spin relaxation lengths are simulated using D’yakonov-Perel mechanisms, with comparisons made by including ripple scattering mechanisms along with phonon scattering. The results are simulated with varying temperatures and concentration.