نشریه شیمی کاربردی روز
پیاپی 36 (پاییز 1394)

In the present work, an electrochemical sensor was constructed by drop casting of carbon nanoparticles/ cellulose nanofiber suspension on the surface of glassy carbon electrode. Developed sensor was successfully applied for determination of folic acid. The combination of carbon nanoparticles/ cellulose nanofibers led to production of a novel electrochemically active nano-composite. The surface characterization of the deposited layer onto glassy carbon electrode was performed by atomic force microscopy and scanning electron microscopy. The voltammetric results showed a considerable enhancement in the anodic peak current of folic acid (about 27 times) on the surface of CNFs/CNPs/GCE relative to the bare GCE. Under optimum conditions, the modified electrode showed a good linear response to folic acid concentration in the range of 0.1–10 µM. High sensitivity, stability, good reproducibility of the electrode as well as low detection limit responses can be considered as significant features of the prepared modified electrode. This sensor was successfully applied for the accurate determination of folic acid in pharmaceutical preparations.

In this research, Mg-Cu-Ferrite nanoparticles was prepared by chemical precipition method. powder phases was determined by X-ray diffraction method and the crystals size mean by sherer formula. The surface morphologies of the nanoparticle were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). As well as for studying the electrical signals resulting nanoparticles electrochemical impedance methods were used. The results show that increasing sintering temperature and subsequent increase in size, causing a significant increase in the electron transfer resulting nanoparticles have been sent. Therefore, the nanoparticles can be as a modification of electrode surfaces used to increase the electrical conductivity.

In this study, hydrogel nanocomposite based on chitosan was synthesized in the presence of montmorillonite nanoclay, then was investigated the water absorption of the hydrogel in distilled water solution with different pH and also by the hydrogel drug release at pH of 1 to 6 and 7.4. For this purpose hydrogel nanocomposite was synthesized monomer glutaraldehyde on chitosan in an acid environment. Hypothetical mechanism for the formation of hydrogel nanocomposite offer and were confirmed structure by FTIR, SEM and XRD. Measuring inflation in distilled water and in solutions with a pH of 1 to 12 showed that the hydrogel nanocomposite synthesized water absorption capacity equal to 221 g / g and also is the maximum amount of water absorption 1 = pH. In the second phase drug into the hydrogel nanocomposite vinblastine drug was loaded and the amount of drug release was measured in simulated body, such as cancer cells (acidic) and peripheral blood (healthy cells pH=7.4 and temperature 37oC).

2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives are important biologically active compounds, which can be evaluated as tyrosinase inhibitors. They are important intermediates in the synthesis of xanthenes that are known as an important class of heterocyclic compounds with biological and therapeutic properties. Several methods have been employed for the preparation of 2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives, including the use of molecular iodine, ultrasonic and microwave irradiation. Some of these methods however, involve harsh reaction conditions. Therefore, further improvement toward milder reaction conditions and higher yields is required. In recent years, the advance of electro-synthesis have attracted organic chemists for having advantages such as short reaction time, high yields with easy work-up and do not require the use of harsh conditions such as high temperature and expensive reagents. In this study, we report a convenient and facile synthesis of 2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) based on electro-catalytic transformation of aldehyde and dimedone in an undivided cell containing an iron electrode as the cathode and a Pt electrode as the anode at a constant current in the presence of potassium bromide as an electrolyte at room temperature.

Nowadays, detection of low concentration of thiourea (TU) in the presence of high amounts of metallic ions is one of the important challenges in different industries, especially electrochemical industries. In this study, the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were performed for study and detection of TU in acidic media containing high concentration of copper(II) ions. In fact, TU measurement was carried out by taking advantage of high affinity of TU and its complexes for adsorption at the Pt nanostructured electrode and changing the charge transfer resistance of Cu2+ as the dominant redox species at the electrode surface. In this work, TU was detected in the range of 0.0-20 ppm in the presence of high amounts of copper ions by applying the appropriate potential in EIS technique, which was obtained from CV studies.

nitro-derived of azospiroptran has been synthesized by the reaction of Fischer's base with 5-((4-nitrophenyl)diazenyl) 2-hydroxy benzaldehyde. 5-((4-nitrophenyl)diazenyl) 2-hydroxy benzaldehyde was obtained from the diazocoupling reaction of para nitro aniline with 2-hydroxy benzaldehyde.With reduction NO2 group another-derived of azospiropyran was obtained. These compounds were characterized by IR and 1H,13C-NMR spectral studies. Investigating their photochromic properties showed an increasing rate of coloration reaction in the present of substitution NH2.

Dyes combinations are one of the most critical pollutants for natural ecosystems in the environment. Dyes sanitation industries such as textile factories to water, reduces the penetration of sunlight and the intensity photosynthesis of aquatic plants and algae in aquatic environments, Therefore damage to the environment. The purpose of this study is to investigate the removal of dyes Brilliant Green from aqueous solutions using absorbent cheap, accessible and easy preparation plant CINERARIA MARITIMA.This was a practical study that was done on a laboratory scale. Various parameters such as PH, contact time between the absorber and dissolved, the effect of the mass of adsorbent to remove dyes for extracting, adsorption isotherms and temperature was investigated. To measure the remaining concentration of dyes was used spectrophotometer at a wavelength of 625 micrometers. To evaluate surface properties of the absorbent SEM device was used for imaging.Overall, the results of this study demonstrate that the activated carbon made of (CINERARIA MARITIMA) can be as an effective absorbent for the removal of Brilliant Green dye used. Thus, in this study it was found that adsorption at neutral PH can be done better. In this study, the optimum amount of contact time and adsorbent mass in concentration 5 ppm were obtained 45 minutes and 0.3 g, respectively. And it was found that absorption obeyed of the Freundlich adsorption isotherm. The absorption data is in agreement with the kinetic model of second grade.

Polyaniline-Graphene Quantum Dot/gold (Au/PANI-GQD) films were prepared by tow step electrochemical process. At the first step, mixture of aniline and GQD was heated and refluxed then electopolymrization performed. At the second step gold’s nanoparticles were dispersed on the surface of PANI-GQD film from galvanostatic condition in the bath containing KAu(CN)2. The electrochemical behavior and electro-catalytic activity of Au/PANI-GQD electrode were characterized by cyclic voltammetry. The morphology of the PANI-GQD film and gold coating on this electrode were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) respectively. Results indicated that gold nanoparticles were homogeneously dispersed on the surface of polyaniline film. The electro-oxidation of ascorbic acid is found to proceed more facile on Au/PANI-GQD electrode than on bare gold electrode. The irreversible oxidation current of ascorbic acid exhibits a linear dependence on the ascorbic acid concentration in the range of 1–5 mM.

In the present research undoped and Pb-doped ZnO nanoparticles with 2%, 4%, and 6% concentration were synthesized by a sol-gel method in gelatin medium. In this process, gelatin was used as polymerization and ende of the growth process agent. Effects of lead concentration on structural of the samples were characterized by several tools. X-ray diffractometer (XRD) indicated wurtzite and hexagonal phase for all samples. Transmission electron microscope (TEM) images showed spherical and hexagonal shapes for all samples that had diameters in the 42-55 nm. UV-visible spectrometer showed a shift in the absorbance peaks for the doped samples and indicated a red shift. Raman results indicated that the NPs were single crystal with hexagonal and wurtzite phase. Finally, photocatalyst application of the NPs was studied to remove methylene blue dye as one of the pollution in environment.

In this research, a titanium dioxide thin film with average particles size of 8 nm was prepared on glass surface and then it's crystalline and optic properties before and after calcinations was investigated. Low angle XRD analyses showed that prepared thin film has mesoporous structured prior to calcination and a further increase in the meso-scale order has been made by calcination. Low angle XRD analyses revealed three peaks related to hexagonal symmetry before and after calcination. Lattice constant of the prepared titanium dioxide before and after calcination, using miller indices of (100) crystal plane calculated to be 147.57 and 143.47 Å, respectively. Transmission spectra of titanium dioxide coating exhibit a significant blue shift in absorption edge and increasing of its transparency after calcination. Indirect band gap of prepared coating estimated from UV-Vis spectra to be 3.69 eV and refractive index of the film and its porosity percentage was calculated to be 1.54 and 67%, respectively.

In this study, Fe-Cr-Cu nanocatalysts were synthesized via two new methods using ammonium tris(oxalate)ferrate(III) and ammonium tris(oxalate)chromate(III) as inorganic precursors. The catalytic activity of the nanocatalysts was investigated for water gas shift reaction and compared a reference sample prepared by impregnation-coprecipitation conventional method. The results revealed that BET specific surface area was higher for the nanocatalysts synthesized by thermolysis of ammonium tris(oxalate) ferrate(III) (88.3 m2/g) and ammonium tris(oxalate)chromate(III) (101.7 m2/g) precursors compared to reference catalyst (73.6 m2/g). Furthermore, the nanacatalysts presented higher catalytic activity than reference sample in the region of 300-500°C as maximum values of CO conversion for the nanocatalysts synthesized by thermolysis of ammonium tris(oxalate) ferrate(III) and ammonium tris(oxalate)chromate(III) (101.7 m2/g) precursors and reference catalyst were 75%, 81% and 61%, respectively.

In this paper, for the first time, a simple and sensitive electrochemical sensor was developed for voltammetric determination of chlorpromazine based on polypyrrole/grapheme oxide (PPy/GO) nanocomposite modified glassy carbon electrode. Polypyrrole has been successfully grown on the surface of graphene oxide nanosheets by using a facile electropolymerization method. The electrochemical response characteristics of the modified electrode toward the oxidation of chlorpromazine were investigated using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The PPy/GO nanocomposite exhibits high electerical conductivity, large surface area and high electrocatalytic activity for the electrochemical oxidation of chlorpromazine. At the optimum pH of 6.0 in 0.1 M phosphate buffer solution, differential pulse voltammograms increase linearly with chlorpromazine concentration over the concentration ranges of 0.005µM –500µM. The detection limits for chlorpromazine was found to be 0.58 nM. The proposed method was also successfully applied to the determination of chlorpromazine in real samples.

In recent years, stabilization of G-quadruplex structures with small molecules has attracted considerable attentions as a promising target for cancer therapy. Quinazolone derivatives (QD) are among the most important classes of ligands that is designed and synthesized to stabilize G-quadruplex structures. Understanding the nature of interactions between the ligands and G-quadruplex is of great importance. To precisely investigate how these interactions can be influenced by structural variation of the ligand, binding interactions of two quinazolone derivatives (QD1 and QD2) with G-quadruplex were studied by molecular docking and molecular dynamics simulation. The results revealed that ligand QD1 has stronger interactions with G-quadruplex than QD2. In fact, side chain shortening of these derivatives play a crucial role in hydrogen bond formation and electrostatic interactions with the phosphate backbone of G-quadruplex which is not obtained experimentally.