نشریه شیمی کاربردی روز
پیاپی 39 (تابستان 1395)

In this study, structural and electronic properties of GanNn clusters (n=1-10) are investigated using formalism of density functional theory (DFT) and projector augmented plane waves (PAW) within VASP software package. Results of calculations show that more tendency of N atoms in more stable structures of small clusters is the formation of building blocks N2 and AWT IMAGE azid, whereas the 3D structures are revealed as cage-like shape with Ga-N bonds. A sharp increase in binding energy per atom from n=1 to n=2 is due to structure transition from 1D to 2D and increase of overlapping between N and Ga orbitals in order to obtain more stability. These changes for clusters with n>3 follow approximately a linear trend. Charge density contour shows an ionic bond with partial covalent character for Ga-N. Also, the lowest energy levels devote to N-s orbitals, middle levels to a hybridized case of Ga-s and N-p orbitals and levels close to Fermi level to a hybridized case of Ga-p and N-p orbitals.

In this study, magnetic multi walled carbon nanotubes were prepared by Dicyclohexyl-18-crown-6 ligand for preconcentration of trace amount of Thallium ions. The optimum pH for maximum absorption of Thallium was between 6-7. Maximum absorption capacity was 39.5 mg of Thallium per gram of adsorbent and the breakthrough volume is 400 mL. Detection limits was 4.67 ng L-1 and the relative standard deviation was found to be 2.9%. Linearity was within the range of 0.024–0.668 µg L-1 with good correlation coefficient (0.998). In this study FT-IR analysis technique and SEM image was performed on nanoparticles. This method is simple, selective and sensitive, and can be applied to the determination of Thallium in various samples.

The potential energy surface of the staudinger reaction of substituted phosphine and an organic azide has been investigated by using Density Functional Theory. Fourteen stationary points related to three different pathways have been located. The different pathways are cis initial attack, trans initial attack and concerted attack, respectively. According to our results the order of the first step energy barrier is Ea cis-attack

Industrial wastewater containing thiocyanate causes increased pollution in rivers and seas. In this research, magnetic nano particles modified by chitosan-Fe (III) used as an efficient adsorbent for removal of thiocyanate from aqueous solutions. Removal percentage of thiocyanate by modified magnetic nanoparticels is more than magnetic non- modified nano particles. The effects of different parameters such as pH , amount of adsorbent, time of stirring and temperature on the removal of thiocyanate has been investigated . Maximum removal percentage (96.7%) were obtained at pH= 4 , 0.03g of adsorbent in 10 min. The results showed that maximum adsorption capacity of the adsorbent is 88 mgg-1. Kinetics isotherms and thermodynamic parameters were studied. The experimental data were correlated reasonably well by Langmuir adsorption isotherm. Kinetic data were well fitted by a pseudo-second order model.Ethanol :aceton solution was applied to regenerate the adsorbent.The results showed that adsorbent could retain its high efficiency after several times of desorption and regeneration. This method is simple, cheap and it could efficiently remove thiocyanate from aqueous solutions .

Nanostructured SAPO-34 and ZSM-5 catalysts are well-known catalysts for the conversion of methanol to light olefins. SAPO-34 catalyst demonstrated higher light olefins selectivity while ZSM-5 catalyst has shown long lifetime. Therefore, combination of these catalysts can lead to the formation of a composite catalyst with optimum light olefins selectivity and longer lifetime. In this study, SAPO-34/ZSM-5 composite catalyst was synthesized with 10 wt.% ZSM-5 loading in initial gel of SAPO-34 via hydrothermal method. Also, pure SAPO-34 sample was synthesized in order to compare with composite catalyst. The synthesized catalysts were characterized by various methods such as XRD, FESEM, EDX, BET and FTIR techniques. According to XRD analysis, it is observed that by ZSM-5 loading to initial gel of SAPO-34, crystallinity reduced. Also, the presence of ZSM-5 in composite catalyst confirmed by small peaks related to ZSM-5. For the composite catalyst, spherical particles were produced with aggregation of small cubic particles. Prepared catalysts were applied in methanol to olefins process to investigate catalytic performance of the samples. Olefins selectivity for both catalysts was rarely similar with time on stream. However, composite catalyst showed longer lifetime and after 1000 min, olefins selectivity reduced with slow rate. Well catalytic performance of composite catalyst could be attributed to the modifying of its properties in the presence of ZSM-5.

A copolymer composed of styrene and acrylonitrile was grafted onto cellulose backbone by free radical polymerization and atom transfer radical polymerization (ATRP) method. First, styrene was grafted onto cellulose Fibers by using suspension polymerization and free-radical polymerization technique. Potassium persulfate (PPS) was used as a chemical initiator and water was used as a medium. We used cellulose-graft-polystyrene as a starting polymer and N-bromosuccinimide (NBS) as a brominating agent to obtain polymers with bromine group. This brominated cellulose fibers were used as an ATRP macroinitiator. This macroinitiator can polymerize acrylonitrile in the presence of CuCl / 2, 2'-Bipyridine (Bpy) catalyst system, in THF solvent at 90°C. The formation of the graft copolymer was confirmed with FTIR, XRD, SEM, TGA and DSC methods.

A simple, rapid, and efficient dispersive liquid-liquid microextraction technique based on ionic liquid (IL-DLLME), followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for the simultaneous preconcentration and determination of cobalt, copper, and zinc in herbal and water samples. In the proposed approach, N,N΄-bis(Salicyliden)-2,2-dimethyle-1,3-propanediamine and acetone were used as the chelating agent and disperser solvent, respectively.1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF6]) was selected as extraction solvent, instead of usage of toxic water-immiscible chlorinated solvents. Some factors influencing the extraction efficiency of metal ions, including type of extraction and disperser solvents, volume of extraction and disperser solvents, sample pH, the amount of chelating agent, extraction time, centrifugation rate, and salt amount were studied and optimized. Under optimized conditions, preconcentration factor of 83, limits of detection (LODs) of 0.88-1.3μg L-1,and the relative standard deviations (RSDs) of 1.95-2.51% (n=8) were obtained. Real samples including mineral water, well water, cabbage, and pomegranate juice were analyzed by proposed method and yielded recoveries ranged from 90.2% to 100.2%. High metal ions recoveries imply on effectiveness of IL-DLLME for efficient preconcentration of metal ions in mentioned real samples.

In this study, a simple and practical method for preparation of new ionic liquids is described. These ionic liquids react with palladium (II) to produce palladium (0) catalyst which is proved by ultra-violet spectroscopy. The use of this new system in Pd-catalyzed Heck reaction provides a useful protocol for the efficient carbon-carbon bond formation in the absence of base. Also, the use of these ionic liquids as reducing agent, ligand and reaction media in base- and copper-free palladium catalyzed sonogashira reaction of aryl halides is explained.

Recently synthesis of amino derivatives of allylidene is highly attended by researchers of organic chemistry because of their unique structure and their ability to form metal complexes containing Cu (II), Ni( II) and Co (II).These compounds can be used as catalyst precursor of conductive polymers.So, the synthesis of open-chain derivatives of the compounds can play an effective role in the above mentioned studies.
In this research project, open-chain derivatives of N-2-3­-aminovinyl amino allylidene ethene-1,2-diamine perchloratehave been synthesized (Scheme 1) by the reaction of vinamidinium salts containing substituents at γ position with diaminomaleonitrile in the presence ofN-ethyldiisopropylamine and methanol.Infrared, the obtained products were characterized by IR, 1H-NMR and 13C-NMR.

In this research, the performance of diethylene glycol (DEG) as corrosion inhibitor on the corrosion of carbon steel A105 sample in 5 M hydrochloric acid and Persian Gulf seawater has been studied using potentiodynamic polarization electrochemical tests and weight loss measurements. The results showed that 50 and 150 ppm of DEG has maximum inhibition efficiency in 5 M hydrochloric acid and seawater, respectively. Also, it was demonstrated that DEG act as a mixed inhibitor in acidic media and as an anodic inhibitor in seawater. Investigation of temperature effect on the DEG performance revealed that the corrosion rate increases as the temperature increased but in 25 °C DEG has the highest inhibition efficiency in seawater. Furthermore, it was elucidated that adsorption process of DEG on the steel surface in both media was best fitted with Langmuir isotherm and adsorption process was perform spontaneously.

Thyme and Trachyspermum ammi are medicinal plants that are famous in the world. These plants are used as antioxidants, antimicrobial, antispasmodic, antiseptic and anticancer. The purpose of this study is identification of potential antioxidant compounds in the essential oils of Thyme and Trachyspermum ammi. For this purpose the obtained chromatogram and antioxidant activity of essential oils were used. The antioxidant activity of essential oils was measured by DPPH radical scavenging test. By coupling of chromatographic data and antioxidant activity assisted by chemometric methods can identify the peaks potentially responsible for antioxidant activity. For this purpose, several linear multivariate calibration techniques such as principal component regression (PCR) and independent component regression (ICR) with different preprocessing methods were applied to chromatogram of essential oils of Thyme and Trachyspermum ammi. The results of these techniques were displayed as regression graphs, which peaks with negative regression coefficients cause antioxidant properties. Finally, GC–MS was used to indicate the structure of chemical components, which were responsible for antioxidant activity.

In this paper, magnetic nanoparticles functionalized with sulfonic acid group as a heterogeneous and recyclable catalyst for the rapid synthesis of 1,5-benzodiazepine derivatives from condensation reaction of 2-phenylenediamine with various Chalcones under microwave irradiation and solvent-free conditions was used. The nano magnetic supported sulfonic acid provides high reactivity and, also it is separated easily from the reaction mixture by using an external magnet. The use of microwaves in solvent free condition compared to conventional heating methods, rapid, simple, safety, high yields and purity of the products of the remarkable advantages of this method is considered.

controlled drug is a process where a carrier has an account with medication can be combined to form the active drug in the body operating the preset desired from this article be abandoned and, therefore, the optimization of the release drug is of special importance. In the present study, Curcumin drug release based on statistical methods that include response surface curve and the method of multivariate modeling can be hard to check, and then optimize the results of drug release both methods can be compared and demonstrated that although the model obtained from the level of responses to experimental, but because the taking effect of the invoices is capable of simultaneously the amount of drug in release Effective factor values that measure has not yet been done as well as anticipated. In addition it's possible to calculate the effect of each factor and higher power in the process of release reviewed.