نشریه پژوهش های شیمی
سال دوم شماره 1 (پیاپی 2، بهار و تابستان 1398)

In this study, since alkaloids are the main substance of many bitter drugs, so structural, electron, reactivity, aromaticity and thermochemical properties of alkaloid purine in the presence of a nanotube and in the absence of nanotubes are investigated. Therefore, the non-bonded interaction of single-wall boron nitride (8.8) with a length of 5 angstroms with theophylline has been studied theoretically. The effects of electron unconsideration, dipole-dipole interactions and spatial suppression on structural and electron properties and the reactivity of the theophylline structure in the presence of single-wall boron nitride nanotubes (8,8), using quantum mechanical calculations of density functional theory at B3LYP and 6-31G * basis set have been reviewed. Frequency calculations were performed to determine the thermodynamic functions and vibration frequencies in the gas phase. Also, NMR isotropic parameters are calculated using the GIAO method to obtain structural information, dynamic behavior and inter-molecular interactions, and the results obtained from NMR spectra are discussed and concluded.

Covalently- modified graphene-polyaniline nanocomposite by interfacial polymerization Soghra Fathalipour*a, Soraya Azizia a Department of Chemistry, Payame Noor University, PO Box: 19395-3697, Tehran Abstract In this work, covalent modified graphene –polyaniline (PANI) nanocomposite with high dispersity in aqueous media was synthesized via interfacial polymerization. First, synthesized graphene oxide (GO) from modified Hummer's method was covalently modified with mercapto ethanol and then reduced with hydrazine monohydrate. Finally, PANI was grafted on modified graphene through interfacial polymerization. Synthesized nanocomposite was characterized with Uv-vis, FT-IR, SEM-EDAX, TEM, XRD and TGA techniques. FT-IR confirmed the modification of GO and synthesis of PANI and XRD spectra showed improvement of crystallinity of PANI in the presence of modified graphene. SEM and TEM images showed the presence of modified graphene and PANI nanostructures.Termogravimitry analysis displayed higher thermal stability of nanocomposite rather than polyaniline and GO. Finally, the electroactivity behavior of grafted PANI on modified graphene oxide was investigated by cyclic voltammetry (CV) method. The results of CV displayed the enhancement of electroactivity of modified graphene in the presence of PANI chains. Keywords: Graphene oxide, Mercaptoethanol, Polyaniline, Thermal behavior,

In this study, a novel and effective sulfonic acid containing organosilica with ionic liquid framework (OIL@SO3H) catalyst is prepared, characterized and its performance is developed in the synthesis of Biginelli products under moderate conditions. The OIL@SO3H material was prepared by simultaneous hydrolysis and condensation of 1,3-bis(3-trimethoxysilylpropyl)-imidazolium iodide and 3-thiopropyltrimethoxysilane followed by treatment with hydrogen peroxide. The OIL@SO3H catalyst was characterized using several techniques such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) , thermal gravimetric analysis (TGA), powder X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analyses. This catalyst was successfully used in the one pot Biginelli condensation of aldehydes with urea and alkyl acetoacetates and delivered corresponding products in high to excellent yields and selectivity under solvent free media. Moreover, the recoverability and reusability of the catalyst were also studied under applied reaction conditions. The result showed that the designed catalyst could be recovered and reused at least four times without significant decrease in stability and efficiency.

In the present study, intermolecular interactions between cation and anion in methylimidazolium tetracyanoborate ionic liquid [Mim+][B(CN)4−] have been studied using B3LYP/6-311G(2d,2p) level of theory. Four ion pairs were found on the potential energy surface. The most stable structures contain both N∙∙∙H–N and N∙∙∙H–C hydrogen bonds. Structures, interaction energies, hydrogen bonding, physical and thermodynamic properties as well as topological properties have been investigated. The effect of different solvents on the stability of complexes and monomers was examined. The thermodynamic properties of ion pairs were calculated using COSMO-RS model. NICS used for indicating of aromaticity of cation ring upon complexation. The NBO results show that in all the ion pairs, the charge transfer taking place from anion to cation. Also, the LPN * (N–H) and LPN* (C-H) donor–acceptor interactions are most important interactions in these complexes. The QTAIM results reveal that all interactions have electrostatic nature. It is predicted that N…H-N interaction is stronger than N…H-C one.

Catalysts in chemical reactions improve the reaction conditions, increase the speed and yield of the products. So, they play a prominent role in various industries such as the chemical industry, petroleum industry, and pharmaceutical chemistry. In this work, an efficient and co-friendly method for the synthesis of 1,2,4,5-tetrasubstituted imidazoles via a four-component condensation of benzil, aldehydes, primary amines and ammonium acetate in the presence of a magnetic nanocatalyst, ZnS-ZnFe2O4, in ethanol under refluxing conditions is presented. Magnetic ZnS-ZnFe2O4 was prepared via a simple method and characterized by energy-dispersive X-ray analysis (EDAX), field-emission scanning electron microscopy (FESEM), X-Ray diffraction pattern (XRD) and vibrating sample magnetometer (VSM). This protocol has advantages such as high yields of the products, use of a green solvent, simple and chromatography-free work-up procedure. Most importantly, the catalyst can be conveniently recovered from the reaction mixture by using external magnet and reused for at least three times without significant decrease in catalytic activity.

An facilitated bulk liquid membrane transport approach is studied for Mg(II) extraction from seawater and RO brine simulated media using 18 crown 6. Seawater, as well as waste of reverse osmosis, contains a lot of magnesium ions, which can be considered as magnesium sources. Here, bulk liquid membrane method is considered for magnesium separation from these sources. Membrane process including solvent lighter than water and 18 crown 6 as carrier was used for extraction and back extraction of magnesium ions as magnesium hydroxide precipitation. Effects of factors such as solvent type, pH, separation time and temperature on extraction were investigated. Results show that the optimal amounts are: cyclohexanone as solvent, extraction pH of 4, extraction time, 62 min and extraction temperature, 35 °C.The selectivity of method was evaluated in presence of Ca2+, Na+, K+ as interferent ions. After optimizing and magnesium separation was tested in real RO waste and seawater.

The aim of this study was to investigate the effects of temperature and time and pH on the labeling of magnetic nanoparticles containing Gallium-68 radioisotope as a high-resolution imaging agent for PET/MRI imaging. Iron magnetic nanoparticles are prepared by a coherent method from a solution containing iron ions 1 and 2 in the presence of ammonium hydroxide, and then coated with silica to increase surface activity and protect nanoparticles against oxidation and to prevent the accumulation of particles (Stöber method). The core-shell nanoparticles were prepared by 3-amino-propyl tri-methoxy-silane (APTES), which has been formulated with amine groups and ultimately attached to the DTPA-causing agent. The use of DTPA results in the intrinsic in vivo stability of this complex. The particle size was measured on the basis of analyzes of about 30-40 nm. The nanoparticles were labeled with GaI-68 at pH =3/5 and the marking efficiency was measured by thin-layer chromatography. The optimum conditions for indicating the temperature of 60 °C and 30 minutes were determined.

Among the various classes of nitrogen-containing heterocyclic compounds, quinoxalines play an important role as a basic skeleton for the design of a number of antibiotics. In addition, quinoxaline ring is a part of several pharmacological active substances of natural or synthetic origin. In this study, an ecofriendly method for the synthesis of cyclobutaquinoxaline-1,2-diol derivatives through cycloaddition reaction of O-phenylenediamine derivatives and squaric acid in EtOH as a green solvent in the presence of a catalytic amount of acetic acid under reflux condition is reported. Different diamine compounds such as 4-methylbenzene-1,2-diamine, 4-chlorobenzene-1,2-diamine, 4-nitrobenzene-1,2-diamine and pyridine-2,3-diamine were used. The structures of products were confirmed by FT-IR, 1H-NMR, 13C-NMR, and elemental analysis.the reaction of 2,3-diaminopyridine with squaric acid give the corresponding cyclobuta[e]pyrido[3,2-b]pyrazine-6,7-diol. According to the spectroscopic data (FT-IR and H-NMR data) in this reaction there might be three isomers in the cyclobuta[e]pyrido[3,2-b]pyrazine-6,7-diol. These isomers are tautomers. In summary, we have developed a new facile and ecofriendly protocol for the synthesis cyclobutaquinoxaline-1,2-diol derivatives from reaction of O-phenylenediamine derivatives and squaric acid.

The leachates from municipal waste are potentially environmental pollutants due to factors such as high chemical oxygen demand (COD) and dark color, and have low natural decomposition ability. Therefore, it is necessary to be treated before entering the environment. The purpose of this research is to investigate the refining potential of leachate from the landfill site of Imam Khomeini port using the Fenton process (Advanced Oxidation). In this project, the leachate was collected from the landfill and refined using the Fenton process and effect of important parameters such as pH solution, amounts of H2O2 and Fe(II) and Different reaction times were investigated and optimized. In the optimum conditions, the maximum amount of COD removal was obtained equal 84% in pH=3, with addition of 3.5 g of Fe(II) sulphate and 10 mL of hydrogen peroxide (30 % w/w). The data show that multi-stage injection of hydrogen peroxide and iron and an increase in reaction time of up to 120 minutes increases the efficiency of the fenton process. The results of this study show the feasibility of using the Fenton method in a significant reduction in the COD content of landfilled lechate in Imam Khomeini port.

Ab initio potential energy curves and transition dipole moments have been calculated for the X1Σ+, A1Δ, B1Π, C1Σ+, D1Π, E1Δ, F1Σ−, G1Π, 31Δ, 21Σ−, 41Δ, 41Π, 31Σ+ and 51Π states of scandium hydride, ScH, using the multi-reference configuration interaction method with large active space and basis sets. Calculations were performed at 50 internuclear distances. Potential energies, dipole moment and transition dipole moments have been computed from 1.0 Å to 20.0 Å. In order to compute Einstein A coefficients and spectroscopic constants, potential energy values and transition dipole moments of the ground and singlet excited states were used in program LEVEL. Einstein A coefficients, Franck-Condon factors and average lifetimes for vibrational levels of excited electronic states for the B1Π - X1Σ+, C1Σ+ - X1Σ+ , D1Π – X1Σ+ and G1Π – X1Σ+ band systems of ScH were calculated. We obtained a lifetime of 90 μs for the v′ = 0 level of the B1Π state and 137 ns for the v′ = 0 level of the C1Σ+ state of ScH. The spectroscopic parameters of the bound states were determined, which agree well with available experimental results.

Synthetic Organic dyes are one of the most important pollutant sources that are used in various industries such as textile, food, pulp and paper mill, cosmetic and hygienic. In this research glutaraldehyde cross-linkined chitosan/polyvinyl alcohol nanofibers was prepared . Cross-linking of electrospun nanofibers were carried out by 5 % glutaraldehyde bath.These nanofibers were used for simultaneous adsorptive removal of tartrazine and indigo carmine dyes from aqueous solutions. The morphology and functional groups of the electrospun nanofibers before and after cross-linking were evaluated using scanning electron microscopy (SEM) and Fourier Transform Infra-Red (FTIR) spectroscopy. The effects of pH, adsorbent dosage, and temperature were studied. Optimum pH value for removal of tartrazine and indigo carmine dyes was found to be 3. The maximum adsorption capacity of tartrazine and indigo carmine were 73/6 mg/g and 85/4 mg/g, respectively. The kinetic and theromodynamic of adsorption followed pseudo-second order model and the Langmuir isotherm, respectively.

In the present study, functionalized magnetic nanoparticles by 3-Mercaptopropyl-trimethoxysilane (MPTMS) for the removal of Hg2+ from aqueous solutions were synthesized. Scaning electron microscopy (SEM) and Fourier transform infrared spectroscopy analyses were used to determine the sorbent characterization. The effect of the operational parameters on the adsorption of Hg2+ by Fe3O4@SiO2@-Si-(CH2)3-SH such as initial pH, adsorbent dosage and the contact time were studied. In addition, the Langmuir and Freundlich isotherm models were applied to the equilibrium data at 25°C. The results revealed that the equilibrium data were fitted well with Freundlich than Langmuir isotherm model. The optimum adsorption capacity of Hg2+ onto Fe3O4 @ SiO2@-Si- (CH2) 3-SH was determined as 20.04 (mg/g) at initial solution PH of 6.0, adsorbent dosage of 30 mg, 15 min contact time. The Hg2+ adsorption kinetic was well described by the pseudo-second order kinetic model. Desorption and regeneration of nanosorbent was investigated. The results showed that the nanosorbent can be regenerated for six times with acceptable sorption capacity.