Journal of Nano Structures
Volume:1 Issue: 2, Summer 2012

A new nano-sized lead(II) coordination polymer, [Pb(2- bpdh)(NO3)2]n(1); (2-bpdh = 2,5-bis(2-pyridyl)-3,4-diaza-2,4- hexadiene)}, was synthesized by a sonochemical method. The structure of 1 may be considered coordination polymer of lead(II) consist of metallocyclicchains formed by bridging NO3 - and 2-bpdh ligands. The thermal stability of compound was studied by thermal gravimetric and differential thermal analyses. The new nano-structure coordination polymer was characterized by scanning electron microscopy, powder X-ray diffraction, elemental analyses and IR spectroscopy. The size of the samples was about 50 nm. Nanoparticles of PbO were obtained by thermolysis of compound 1 in oleic acid as a surfactantat 180°C under air atmosphere and the size of this PbO particles were about 50 nm.

In the present study, the interaction between nano-TiO2 and lysozyme was investigated by the method of UV-Vis detection and fluorescence spectroscopic techniques. The thermal denaturation of lysozyme has been investigated in the presence and absence of nano-TiO2 over the temperature range (293-373) K in different buffer and pH, using temperature scanning spectroscopy. The presence of nano-TiO2 caused the destabilization of lysozyme resulting in a decrease in the temperature of unfolding with an increase in nano-TiO2 concentration.

Fe3O4 nanoparticles were synthesized via a simple chemical reaction between FeCl2.4H2O and Fe(NO3)3.9H2O under nitrogen atmosphere at room temperature, and then nanoparticles were added to cellulose acetate (CA) polymer. The influence of nanoparticles on the thermal properties of CA polymeric matrix was studied using thermogravimetric analysis (TGA). Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The magnetic properties of the samples were also investigated using an alternating gradient force magnetometer (AGFM). We found that the Fe3O4 nanoparticles exhibit a ferromagnetic behavior with a saturation magnetization of 59 emu/g and a coercivity of 105 Oe at room temperature.

Two new heterogenized epoxidation nanocatalysts based on molybdenum and tungsten compounds were prepared with covalent grafting of MCM-41 with 3-aminoropropyl trimethoxysilane and subsequent reaction with diphenylphosphinobenzaldehyde and complexation with M (Mo, W)O2(acac)2. X-ray diffraction and nitrogen sorption analyses revealed the preservation of the textural properties of the support as well as accessibility of the channel system despite sequential reduction in surface area, pore volume and pore size. Elemental analyses showed the presence of 0.15 mmol molybdenum and 0.09 mmol tungsten per gram of the catalyst, respectively. Epoxidation of olefins in the presence of M (Mo,W)O2dppb@AmpMCM-41 with tert-butyl hydroperoxide (TBHP) and hydrogen peroxide were examined.

MnTiO3-Zeolite-Y nanocomposites were synthesized with 5-10-20% (w/w) of MnTiO3 by stearic acid gel method. Then, the gels were calcined at 900 °C for 4 hours and the resulted spectra were investigated at 20% (w/w) concentration. Also, the presence of rhombohedral phase of MnTiO3 in Zeolite-Y matrix was confirmed by XRD, SEM, EDX and BET. The VSM results showed the antiferromagnetic properties for the 20% nanocomposite. The photocatalytic activity of the nanocomposites was finally evaluated by degradation of methylene blue and calcon reagents in aqueous solution.

Cauliflower-like nanostructure of cadmium oxide was synthesized by utilizing mechanochemical reaction followed calcination procedure for the first time. The design of experiment (DOE) by Taguchi method was used to study influence of the chosen factors and to consider optimum conditions of the experiments. The temperature of calcining, the duration of milling, the duration of calcining and reactants molar ratio (M/L) are four chosen factors for DOE. The value of band gap energy was calculated through UV-visible absorption spectroscopy and Tauc relation. Data analysis was performed using Minitab and Qualitek-4 statistical softwares. The optimum conditions for preparing cauliflower-like structure were predicted and also, influence of each factor was determined. The temperature and duration of calcining with the percentage contribution of 68.23 and 17.72%, respectively are the most effective factors at this design.

In this study, we investigated the effect of using large TiO2 nanoparticles in the matrix of small nanoparticles to improve the performance of dye-sensitized solar cells (DSSCs), as light scatter to increase the light harvesting. The mixed powder was deposited by electrophoretic deposition (EPD) on FTO (F-SnO2 coated glass). It is shown that adding small quantity of larger nanoparticles can enhance the performance of DSSCs. This paper also studies the deferential scanning calorimetry (DSC) of mixed powders to detect the phase transitions, due to the change of weight percentage between large and small nanoparticles.

In this paper, a nanostructured modified electrode was fabricated by incorporating of 2,2′-[1,9-nonanediylbis(nitriloethylidyne)]-bishydroquinone (NNH) as a newly synthesized modifier and TiO2 nanoparticles to the carbon paste (MTCPE) and then was used for the electroanalysis of epinephrine (EP). The electrochemical studies were carried out by using cyclic voltammetry, chronoamperometry and differential pulse voltammetry (DPV) techniques. It has been found that the oxidation of EP at the surface of this electrode occurs at a potential about 235 mV less positive than that of an unmodified carbon paste electrode. A dynamic range of 1.0–2000.0 μM, with a detection limit of 0.37 μM for EP, was obtained using DPV. Also, this modified electrode exhibits well separated oxidation peaks for EP and acetaminophen (AC) using DPV.

CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor and solid state reaction. Effect of calcinations temperature and quantity of surfactant on particle size has been investigated. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT–IR) spectroscopy.

Abstract Diels–Alder [2+4] cycloaddition products of the reaction between C20 and C4H4X2 or C2O2X2 (X = H, F, Cl, CH3, NH2, NO2, and OH) were studied atB3LYP level of theory with 6-31G, 6-31G(d, p) and 6-311G(d, p) basis sets. The HOMO–LUMO gaps of Kohn–Sham orbitals for most of the adducts show evident increase compared with the gap value of C20, suggestive of more stability in the adducts. The thermodynamic calculations indicate that the reaction of diene with C20 is exothermic and spontaneous. While, the addition of 1,2-dioxos to C20 can be thermodynamically improper when the 1,2-dioxo group consists of electronegative atoms.