Effects of length and number of aromatic rings in carboxylic acid ligands on structure and optical properties of lead(II) coordination polymers

Research on Chemical Intermediates - To systematically examine the effects of the length and number of aromatic rings in carboxylic acid ligands on the structure and properties of lead(II)...     

Selective formation of spiro dihydrofurans from one-pot reaction of dimedone with BrCN and aldehydes in the presence of Et3N

Reaction of 5,5-dimethylcyclohexane-1,3-dione (dimedone), aldehydes and cyanogen bromide in the presence of triethylamine leads to the selective formation of spiro dihydrofurans in moderate to good yields at room temperature.     

Investigation of the equality constraint effect on the reduction of the rotational ambiguity in three-component system using a novel grid search method

The obtained results by soft modeling multivariate curve resolution methods often are not unique and are questionable because of rotational ambiguity. It means a range of feasible solutions equally fit experimental data and fulfill the constraints. Regarding to chemometric literature, a survey of useful constraints for the reduction of the rotational ambiguity is a big challenge for chemometrician. It is worth to study the effects of applying constraints on the reduction of rotational ambiguity, since it can help us to choose the useful constraints in order to impose in multivariate curve resolution methods for analyzing data sets. In this work, we have investigated the effect of equality constraint on decreasing of the rotational ambiguity. For calculation of all feasible solutions corresponding with known spectrum, a novel systematic grid search method based on Species-based Particle Swarm Optimization is proposed in a three-component system.     

Calculation of optical and electronic properties of zinc sulfide produced thin layers under different deposition angles

Zinc sulfide nano layers were deposited on glass substrates at 300 K by physical vapor deposition method, under high vacuum conditions and different deposition angles. Thickness of the layers were measured 73 nm, by quartz crystal method. Optical reflectance and transmittance of the layers were measured in the wave length of 300?C1100 nm. Optical constants were calculated by Kramers-Kronig relations. The influence of deposition angle in optical properties of ZnS nano layers are investigated. By using Generalized Gradient Approximations in context of plane wave pseudo-potentials (norm conserving and Ultrasoft) and full-potential linearized augmented plane wave methods, Band structure calculated and compared with experimental results. Possible energy transitions are also reported.     

Erratum to: The catalytic effect of Al-KIT-5 and KIT-5-SO3H on the conversion of fructose to 5-hydroxymethylfurfural

Research on Chemical Intermediates -     

Rapid production of monodisperse cross-linked red blood corpuscle-like particles via scalable one-pot dispersion polymerization

Cross-linked polystyrene (PS) particles having red blood corpuscle (RBC)-like shape were synthesized by one-pot dispersion polymerization of styrene with ethanol/water mixture and ethylene glycol dimethacrylate (EGDMA) as the reaction medium and cross-linker, respectively. Monitoring of the reaction showed that RBC-like shape forms due to asymmetric shrinkage of a cross-linked network during the phase separation. In addition, three dimensional phase diagram was generated based on the yielded data that showed that the formation of such unique shape extremely depends on the polarity of the medium and injection time of the cross-linker. In situ synthesis of RBC-like particles, as promising biomaterials in targeted drug delivery and a model for the understanding of the cell behavior, via such fast and high solid content approach makes it to be conducive to subsequent scale up, i.e. potential commercial adoption.     

Structure and properties of NR/BR blend/clay nanocomposites prepared by the latex method

Rubber blend/clay nanocomposites based on the 50/50 (wt %) natural rubber/butadiene rubber was prepared by the latex method via mixing the latex of 50/50 NR/BR blend with different amounts of the aqueous sodium montmorillonite (Na-MMT) dispersion and co-coagulating the mixture. XRD and TEM were used to characterize structure of the nanocomposites. It was found that fully exfoliated structure could be obtained by this method only when the low loading of layered silicate (up to 5 phr) is used. With increasing the clay content, both non-exfoliated (stacked layers) and exfoliated structures can be observed simultaneously in the nanocomposites. Nanocomposites showed mechanical properties better than the clay-free volcanizate. Moreover, modulus, tensile strength, elongation at break and tear strength increased significantly by increasing the clay amount up to 5 phr and then remained almost constant by further increasing the clay content. Improvement in the mechanical properties by increasing the clay loading up to 5 phr was attributed to the nano-reinforcement effect of Na-MMT. TGA results indicated an improvement in the main decomposition temperature by increasing the clay amount.     

Nano composite system based on coumarin derivative–titanium dioxide nanoparticles and ionic liquid: Determination of levodopa and carbidopa in human serum and pharmaceutical formulations

The combination of coumarin derivative (7-(1,3-dithiolan-2-yl)-9,10-dihydroxy-6H-benzofuro[3,2-c]chromen-6-on), (DC)–titanium dioxide nanoparticles (TiO₂) and ionic liquid (IL) yields nanostructured electrochemical sensor, formed a novel kind of structurally uniform and electrocatalytic activity material. This new ionic liquid–TiO₂ nanoparticles modified carbon paste electrode (IL–CTP) due to its enhanced conductivity presented very large current response from electroactive substrates. The modified electrode was characterized by different methods including a scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and voltammetry. A pair of well-defined quasi reversible redox peaks of coumarin derivative was obtained at the modified carbon paste electrode (DC/IL–CTP) by direct electron transfer between the coumarin derivative and the CP electrode. Dramatically enhanced electrocatalytic activity was exemplified at the DC/IL–CTP electrode, as an electrochemical sensor to study the electro oxidation of levodopa (LD) and carbidopa (CD). Based on differential pulse voltammetry (DPV), the oxidation of LD and CD exhibited the dynamic range between 0.10– 900.0 μM and 20.0–900.0 μM respectively, and the detection limit (3σ) for LD and CD were 41 nM and 0.38 μM, respectively. DPV was used for simultaneous determination of LD and CD at the DC/IL–CTP electrode, and quantitation of LD and CD in some real samples (such as tablets of Parkin-C Fort and Madopar, Sinemet, water, urine, and human blood serum) by the standard addition method.