Nanochemistry Research
Volume:4 Issue: 2, Summer-Autumn 2019

In this study, Fe3O4@SiO2-PAF-SO3H nanocomposite was successfully fabricated by immobilization of sulfonic acid groups on the surface of poly(anilin-formaldehyde)-supported on magnetic Fe3O4@SiO2 nanoparticles through layer-by-layer assembly. Fe3O4@SiO2-PAF-SO3H composite nanostructure has been fully characterized using various techniques including the Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction patterns (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and vibrating sample magnetometry (VSM). The one-pot synthesis of mono and bis 1,4-dihydropyridine derivatives, as pharmaceutically interesting compounds, have been achieved in high yields via three-component and pseudo five component condensation of an aromatic aldehyde, ammonium acetate and ethyl acetoacetate in the presence of Fe3O4@SiO2-PAF-SO3H as a novel retrievable hybrid nanocatalyst under solvent-free conditions. This protocol has advantages in terms of short reaction time, solvent-free condition, high yield and purity, easy work-up and eco-friendly process as well as recyclability of the nanocatalyst (at least 6 times) with no decrease in catalytic activity.

In this study, the scintillation and optical properties of pure and silver doped potassium chloride (KCl:Ag) single crystals were reported. Pure and doped KCl bulk single crystals with a good optical quality and free from cracks were grown from the melt using Czochralski technique. Different analysis methods were used to study the optical and scintillation properties of the grown crystals. The XRD, EDX and SEM results confirmed the formation of KCl compound. The UV excitation, X and gamma rays were employed to evaluate the scintillation and optical properties of the synthesized samples. The X-ray induced luminescence spectrum of doped crystal showed the prominent blue emission at 400-460 nm wavelength region. Also, the thermoluminescence response of doped sample showed a strong TL glow peak at 200 and proper linear ranges as a function of dose making it a promising candidate for dosimetry and photonic applications.

In this paper, three techniques to obtain capped magnetite nanoparticles were compared. In the formation of magnetite nanoparticles via the co-precipitation route, capping agents were introduced pre-, simultaneously with, or post-addition of the precipitating agent, ammonia. The amino acids L-glutamine and L-glutamic acid were used as the capping agents. Characterization via TEM, pXRD, EDX, and magnetic analysis displayed that the stage of introduction affected the properties of the nanoparticles obtained. Confirmation of capping was performed by FTIR and X-ray photoelectron spectroscopy. TEM displayed that the post-addition method yielded nanoparticles with the narrowest size distributions, having attractive dispersity values. The pre- and simultaneously-introduced methods produced smaller nanoparticles but had relatively higher size distributions. Crystallite size determined from pXRD showed that the post-addition method had the highest crystallite size, even compared to the uncapped nanoparticles, while the pre-introduced were much less crystalline. From the magnetic studies, the post-introduction method was shown to yield the highest magnetic saturation values, even when taking magnetically dead layers into account. It was also shown that the simultaneous and pre-introduction methods yielded similar magnetic saturation values despite size differences.

The palladium nanoparticles were immobilized on DNA-modified multi walled carbon nanotubes as stable and powerful heterogeneous catalyst. The catalyst was characterized by FT-IR spectroscopy, UV-Vis spectroscopy, field emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma and elemental analysis. DNA as a well-defined structure and biodegradable natural polymer was used to make the palladium catalyst which shows a high activity in Suzuki and Sonogashira cross-coupling reactions in excellent yields and good selectivity under ligand-free and mild reaction conditions. Moreover, the catalyst could be recovered and reused several times without any considerable loss of its catalytic activity. This air- and moisture-stable phosphine-free palladium catalyst was found to be highly active in aqueous ethanol with extremely small amount of palladium under mild conditions. To the best of our knowledge, this is the first report on using DNA base heterogonous catalyst for Suzuki and Sonogashira cross-coupling reactions.

In this work, α-Fe2O3 (hematite) nanoparticles were synthesized using Arabic gum (AG) as a biotemplate source by the sol-gel method. This method has many advantages such as low-cost, nontoxicity, simple work-up, high efficiency, compounds uniformity, and high efficiency. The α-Fe2O3 nanoparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results of XRD analysis revealed the formation of the rhombohedral phase of α-Fe2O3 nanoparticles with an average crystallite size of 19 nm. The TEM image illustrated the α-Fe2O3 nanoparticles with average particle size of 45-50 nm. The application of α-Fe2O3 nanoparticles as a photocatalyst was investigated for the degradation of the Congo red dye. The effects of photocatalyst dosage, initial dye concentration and visible light irradiation on dye degradation were assessed. The results demonstrated that the catalyst could degrade90% of the Congo red dye in 90 min. The α-Fe2O3 nanoparticles exhibited slight decrease in photocatalytic degradation of Congo red dye after four recycles.

Template-free CuO nanorods were synthesized through a three-step chemical method with no water-insoluble materials. The first step included the preparation of a Cu-complex, which was obtained from dipicolinic acid, L-lysine, and copper nitrate. Then, as the second step, the obtained solution was allowed to be relaxed for a week to and formation of some blue single-crystals single crystals, which would be assigned as a square-pyramidal copper complex by according to study analyzing its single-crystal single crystal structure. Finally, as the third step, the blue prepared Cu-complex should be calcined to synthesis the CuO phase. Simultaneous thermal analysis (STA) was utilized to determine the optimum calcination temperature. Its results and showed that 600 ºC is the optimum temperature. X-ray diffraction (XRD) analysis approved the formation of the CuO phase without any impurity which is matched with the monoclinic CuO standard lines (PDF No.: 74-1021). Especially, the as-prepared CuO powder has shown clear nanorod morphology in transmission electron microscopy (TEM) images and exhibit a notable optical behavior and high band gap bandgap energy (Eg = 2.8 eV) in comparison to that of bulk CuO (Eg = 1.9-2 eV).

Co3O4/NiO@GQDs@SO3H nanocatalyst has been used as an effective catalyst for the preparation of benzopyranopyridines through a four-component reaction of salicylaldehydes, thiols and 2 equiv of malononitrile under reflux condition in ethanol. The catalyst has been characterized by FT-IR, XRD, SEM, EDS, BET, XPS, TGA and VSM. Atom economy, reusable catalyst, low catalyst loading, applicability to a wide range of substrates and high yields of products are some of the notable features of this method. The best results were gained in EtOH and we found that the reaction gave convincing results in the presence of Co3O4/NiO@GQDs@SO3H nanocomposite (4 mg) under reflux conditions. A series of salicylaldehydes and different thiols were studied under optimum conditions.We also determined recycling of Co3O4/NiO@GQDs@SO3H nanocomposite as catalyst for the model reaction under reflux conditions in ethanol. The results showed that nanocomposite can be reused several times without noticeable loss of catalytic activity (Yields 90 to 88%)

Metal oxide nanoparticles (NPs) produced by green chemistry approaches have received notable attention because of their significant physic-chemical properties and their remarkable uses in the area of nanotechnology. Currently, the sustainable improvement of synthesizing NPs by distinctive parts of plant extract has become a major focus of scientists and researchers because of these NPs have minimum pernicious effect in the ecosystem and minimum noxiousness for the human health. Among the all metal oxide nanoparticles, alumina nanoparticles (Al2O3 NPs) draw peculiar attention due to their significant applications in ceramics, textiles, drug delivery, catalysis, waste-water treatment and biosensor. Many natural biomolecules in plant extracts such as saponins, tannins, alkaloids, amino acids, enzymes, proteins, coumarins, polysaccharides, polyphenols, steroid and vitamins could be participated in bioreduction and stabilization of Al2O3 NPs. In the last decade, innumerable efforts were made to develop a sustainable eco-accommodating method of synthesis to avoid the perilous byproducts. In this review, I focused on the plants which are used for the green fabrication of Al2O3 NPs, their characterization methods and applications are investigated.

In this study, Cu, Ag, and Fe nanoparticles (NPs) are used in shampoo, hand washing liquid (HWL) and dish washing liquid (DWL) instead of the conventional synthetic preservatives such as isothiazolinones; since the latter often act as potent sensitizers that leads to development of allergic contact dermatitis. The above NPs are considerably effective against Escherichia coli and Staphylococcus aureus. Our metal NPs are deliberately made durable and pure through arc fabrication. They appear in spherical morphology as indicated by XRD and SEM. This study clearly demonstrates the advantages of using rather low concentrations of Ag, Cu and Fe NPs as preservatives instead of carcinogenic Kathone CG, which is commonly used in detergent products.The shampoo formulation with 0.1 g/L Cu NPs and HWL and DWL with 0.1 g/L Ag NPs exhibit the best antibacterial activity against tested E. coli and S. aureus. Generally, the order of antibacterial activity of these preservatives is: Cu NPs>Ag NPs> Fe NPs.