نشریه شیمی کاربردی روز
پیاپی 27 (تابستان 1392)

The Two-dimensional Quantitative Structure-activity Relationship (2D-QSAR) of a series of 44 triazine derivatives with antischizophrenia and antihuntingdon’s property has been studied. Multiple Linear Regression (MLR)، Principal Component Regression (PCR) and Partial Least Squares (PLS) were used as regression analysis techniques with an attempt to derive a correlation between the biological activity as dependent variable and various descriptors as independent variables. The QSAR studies were performed using VLife MDS software. The models were validated for predictivity by both internal (q2) and external (Pred_r2) validation. Results indicated this is no significant statistical differences between calculated activities of these compounds with laboratory quantities thus، the obtained models allowed us to predict Antischizophrenia and Antihuntingdon activities of new Triazines derivatives.

A simple، rapid and sensitive method for the determination of cetrimonium bromide at trace levels in water samples was developed by combining a dispersive liquid –liquid microextraction (DLLME) technique with high performance liquid chromatography (HPLC-UV). A mixture of extraction solvent and dispersive solvent were rapidly injected into 10. 0 mL aqueous sample، and a cloudy solution was formed. After extraction of the analyte into the fine droplets of extractant، phase separation was performed by centrifugation and the enriched analyte in the sedimented phase was determined by HPLC-UV. The factors relevant to the microextraction efficiency، such as the kind and volume of extraction and dispersive solvent، and the extraction time were optimized. Under the optimum conditions (extraction solvent: chlorobenzene، volume، 70 μL; dispersive solvent: ethanol، volume، 0. 75 mL)، the enrichment factor of 200 was obtained. The linear range was 0. 005–100 µg L-1. The relative standard deviation of 5. 9% (n= 5)، and detection limit (signal-to-noise ratio of 3) of 0. 10 pg mL-1 were obtained.

This paper reports the effect of Sn doping on structural and optical properties of CuO nanoparticles prepared by the simple hydrothermal method in mild condition without pH adjustment and surfactant. The structural and optical properties of these CuO and Sn doped CuO particles were investigated using X-ray powder diffraction (XRD)، Scanning electron microscopy (SEM)، Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectroscopy (PL). powder X-ray analysis reveals that Sn+4 ion have substituted the Cu+2 ions without changing the monoclinic structure of CuO but the average particle size of nano CuO increases from 16 nm to 22 nm. The PL emission spectra revealed blue shift after introducing Sn into the CuO and an intensity decreasing as well.

Polythiophene is a standout amongst the most valuable sorts of the conducting polymers that hold numerous odd physical and electrical lands for instance dissolvability، electrical conductivity and develop the ecologically and thermally stable materials. Distinctive assembling techniques have been advanced for conducting polymer nanostructures and near them، template method is a facile and encouraging method. Nanostructured polythiophene was prepared by soft-template method in the vicinity of sodium dodecyl sulfate (SDS) as an anionic surfactant، triethanolamine (TEA) as a co-surfactant and ammonium persulfate (APS) as an oxidant in aqueous medium. Moreover، the chemical structure of fabricated nanostructured polythiophene was investigated by fourier transform infrared (FTIR) spectroscopy. The morphology and particle size of the product was studied by scanning electron microscope (SEM) and atomic force microscope (AFM). Furthermore، dispersion state of nanostructured polythiophene in organic solvents was studied after being dried. The results indicate that nano-product has a favorable fiber-like-structure with a diameter in the range of 85–100 nm.

A new fluorescent nano-chemosensor (L) has been synthesized and characterized by 1H NMR، 13C NMR، COSY، HSQC، DEPT، IR spectroscopy، elemental analyses and scanning electron microscopy. The fluorescent nano-chemosensors with size about 30 nm were prepared by nanoprecipitation method. The chemosensor L showed selectivity to Al3+ and Cr3+ cations in EtOH/H2O (1:1، v/v) mixture. This chemosensor also exhibited an improved sensitivity and selectivity to Al3+ and Cr3+ cations when used as insoluble nanoparticles in aqueous buffer solution.

Metal doped ZnO (MZO، metal = Ag، Cd، Cu) with different metal ion doped concentrations were synthesized by sol-gel method. The structural and optical properties were characterized by UV–Vis spectroscopy and Fourier transform infrared (FT-IR). With metal ion doping content increase، a red shift in band gap is observed. The red shift in band edge absorption peak in UV-Vis absorbance spectrum with increasing metal content also confirm the doping of metal in ZnO nanostructure. The band gap of ZnO resistivity was also changed according to the metal doping amounts and a kind of dopant. The results showed that each metal ion that has closer ionic radius to Zn2+ could change optical band gap more than other.

The electrocatalytic oxidation of cysteine on multi-wall carbon nanotubes glassy carbon electrode (MWCNT-GCE) in phosphate buffer solution in pH (4. 0) has been characterized using cyclic voltammetry، chronoamperometry and differential pulse voltammetry. The results showed that the catalytic current of 1،5-bis (3،4-dihydroxy phenyl) penta-1،4-dien-3-one (BPO) depended on the concentration of cysteine. Although cysteine itself showed a very poor electrochemical response at the glassy carbon electrode، the response could be greatly enhanced by using BPO as a mediator، which enabled a sensitive determination of cysteine. The kinetics parameters of this process were calculated، the apparent catalytic rate constant (k΄h) and electron transfer (a) were 867 M-1s-1 and 0. 57 respectively. The differential pulse voltammetry response of the modified MWCNT-GCE was linear against the concentration of cysteine in the range 0. 5 to 30 μM the limit of detection was found to be 0. 17μM.

Computer circuit boards (CCBs) are valuable because of their precious metal contents. In this regard، the recovery of gold from CCBs has attracted great interest. In this work، we report the recovery of gold from CCBs with different reductants. The CCBs were first crushed mechanically to obtain particles with sizes less than 0. 1 mm. The powders were then leached with nitric acid to remove undesired metals. The remaining was then treated with aqua regia to dissolve gold ion. The dissolved gold was then precipitated from the leachate with hydrazine، ferrous sulfate or oxalic acid and the effect of these reductants on the recovery of gold was studied. We were able to recover more than 99% of gold from CCBs with purity of about 99. 5%.

Recently، TiO2 is one of the most important materials in the field of photocatalytic activity. In the present study، Co-TiO2، Nd-TiO2، and Co،Nd-TiO2nanocomposites powders were prepared via sol-gel method. Moreover، the advantage of metal doping and co-doped effects on photocatalytic activity were investigated. Structure and photocatalytic activity were studied by several methods such as: FT-IR spectra، Scanning Electron Microscopy (SEM)، and X-Ray Diffraction (XRD). The results have revealed that Co،Nd-codoped TiO2 nanocomposite has better photocatalytic activity in comparison with Co-doped TiO2 and Nd-doped TiO2nanocopmosites.