نشریه پژوهش های شیمی
سال سوم شماره 1 (پیاپی 4، بهار و تابستان 1399)

This study is devoted to the estimate the longitudinal, bulk and shear stress auto correlation functions (LSAC/BSAC/SSAC) and corresponding viscosities of evaporated Na for four thermodynamic states. In fact, this study is devoted to investigating temperature dependence of BSAC/LSAC/SSAC functions. This expression is written as a time integral of a time correlation function of a quantity corresponding to the transport coefficient. To investigate transport coefficients theoretically, the method used more frequently is the Green-Kubo formula. Another quantity required to evaluate the LSAC/BSAC/SSAC functions is the distribution function. For this aim, we have used the results work of Kahl and Kambayashi having been done via molecular-dynamics (MD) simulation method. First, three non-zero sum rules for the longitudinal and bulk stress auto correlation functions have been evaluated. For the interaction potential, we have used Ashcroft pseudo potential and corresponding pair correlation function. The Green-Kubo method and Mori memory function formalism coupled with the frequency sum rules have been used to calculate the viscosities. The estimate of the shear, bulk and longitudinal viscosities of evaporated Na for four thermodynamic states has been presented.

Fusion of a ring segment through the formation of two new bonds at the expense of two other (weaker) bonds is a transformation which were always at the center of chemists‘ attention. Maleimides have aspiration for involvement of both their olefinic carbons in the reactions in which they take part. In this study, for the first time the synthesis of benzo [e] isoindole-1,3- diones using copper promoted one pot reaction of styrene derivatives with maleimides is reported. This is the first report on the Diels-Alder reaction of styrenes as dienes with the ene systems. in addition, valuable naphtho [1,2-c] furan-1,3- diones derivatives are synthesized via the reaction of maleic anhydrides with styrenes (using maleic anhydride instead of derivatives of maleimide). Use of commercially available styrenes as raw materials as well as the direct synthetic strategy of the invented procedure led to high yields of products for the synthetic organic chemists.

Quantum calculation were carried out to investigate interaction between sitagliptin and piogliazone as diabetic drugs with single-walled carbon nanotubes (7, 7). In all calculations, the generalized gradient approximation (GGA) with double numerical (DND) was used. The reactivity regions and sites of nuleophilic and electrophilic these compounds are investigated using fukui functions basis on the Mulliken population analysis (MPA). The adsoption energies of sitagliptin and piogliazone on single-walled carbon nanotubes (7, 7) were calculated. Sitagliptin and piogliazone drugs were located inside SWCNT. The quantum molecular descriptors (ionization potential (I), vertical electron affinity (A), hardness (η), chemical potential (μ), softness (S), electrophilicity (ω) and electronegativity (χ)) of pristine SWCNT and SWCNT-drug complex are calculated. The negative values of adsorption energies indicate such interactions can be conceived as physicosorption. Data display that the adsorptions are exothermic and spontaneous. The obtained results show that the SWCNT (7, 7) can be reliable to perform as a carrier for sitagliptin and piogliazone molecules in drug delivery.

Density functional theory (DFT) was used to study the chemoselectivity of acetylene hydratase in hydration of 3-butyn-2-ol, propargyl alcohol and propen. A quite large model of the enzyme’s active site was made, based on its crystal structure. Geometrical structures of the stationary points along the reaction paths were optimized, and energy profiles of the reactions were obtained. The results showed that the binding energy of 3-butyn-2-ol is 16.1 kcal/mol higher than the binding energy of the enzyme’s normal substrate (acetylene), but the corresponding reactant is 17.4 kcal/mol more stable. Similarly, propargyl alcohol’s binding energy is 10.7 kcal/mol more than binding energy of acetylene. In the third step of the reaction, propargyl alcohol reaches to a very stable intermediate and its reaction stops. These show that 3-butyn-2-ol and propargyl alcohol act as competitive inhibitors of acetylene hydratase. The results showed that binding of propen is very endothermic than binding of the other compounds (30.3 kcal/mol). In addition, the next nucleophilic attack is also very endothermic. In summary, propen cannot be hydrated by acetylene hydratase.

Derivative spectrophotometric and Taguchi orthogonal design was used for determination and optimization of simultaneous removal of Direct red and Reactive black by Cobalt ferrite nano-particles modified with PDA from an aqueous solution in a batch system. Cobalt ferrite nano-particles were prepared using the co-precipitation method. The sorbent was characterized by FT-IR spectroscopy, SEM, and XRD techniques. Effective factors on adsorption process, such as amount of sorbent, initial concentration of dyes, pH value, and time were considered using a L16 Taguchi orthogonal array design. Taguchi analysis is based on choosing the best run by analyzing signal-to-noise ratio (S/N), whose form depends on the experiment objective. Thus, the removal percentage (R%) and capacity uptake (q) of dyes were transformed into an accurate S/N ratio for a “high is better” response. The best conditions for adsorption of dyes were determined by the Taguchi method and desirability approach as pH = 3, sorbent dose of 10 mg , initial reactive black concentration of 200 mg L−1, initial Direct red concentration of 200 mg L−1, and contact time of 4 min.

This project studies the absorption and removal of copper cations from aqueous solutions by starch-poly (acry-lamide-co-acrylic acid) / graphene oxide hydrogel bio-nanocomposites. The bio-nanocomposite hydrogel was obtained from a radical polymerization of the starch biopolymer with vinyl acrylamide (Am) and acrylic acid (AA) monomers with N,N-methylenebisacrylamide (MBA) in the presence of graphene oxide nanosheets (GO). The bio-nanocomposites were investigated by XRD, FT-IR, FE-SEM, TEM and TGA techniques. The effect of pH on adsorption, effects of time on adsorption, the initial concentration of copper ions and effect of temperature on the adsorption process on copper ions were investigated. The results which obtained from the experiments on the removal and absorption of copper ions were shown the maximum adsorption at pH =5 / 5, the adsorption increased by increasing the time, the equilibrium adsorption process flowed by Langmuir isotherm model and according to thermodynamic parameters, the adsorption of Cu2+ on bio-nanocomposite hydrogels occurred endothermic process and spontaneously, respectively. Also, the amount of adsorption increases proportionally to the amount of GO. Additionally, because of the enthalpy of absorption between 20-80 (KJ / mol), as a result, the process of removal is an electrostatic process

This paper investigates the interaction of carbon nanotube with Trinitroanisole by density functional theory. For this purpose, the structures of Trinitroanisole, carbon nanotube and their derived products at two different configurations were optimized geometrically. Then, IR and frontier molecular orbital computations were implemented on them. The calculated thermodynamic parameters including Gibbs free energy changes (∆Gad), adsorption enthalpy variations (ΔHad) and thermodynamic equilibrium constants (Kth) demonstrated that adsorption of Trinitroanisole is exothermic, spontaneous and irreversible. The effect of doping carbon nanotube with tin was also checked out and the findings indicated that by supplanting carbon with tin, the adsorption process remain exothermic, spontaneous and experimentally feasible. The influence of temperature was also evaluated and the results revealed that 298 K is the optimum temperature for the desired process. The obtained specific heat capacity values proved that by interaction of carbon nanotube with the studied explosive, the heat sensitivity has declined significantly. And this abate has become more intensified by doping carbon nanotube with tin. The structural feature such as density values and N-O and C-NO2 bond lengths substantiated that the detonation pressure, explosive velocity and destructive power of the energetic materials have defused drastically after the adsorbing on the surface of carbon nanotube. The orbital molecular findings indicated that Trinitroanisole have become less reactive, conductive and electrophile after the interaction with nanostructure and this nanostructure can be used for developing novel electrochemical sensors for detection of Trinitroanisole.

Several studies have been carried out to remove and reduce nitrophenol from contaminated water and industrial effluents, and various methods have been used such as catalytic electrochemical and so on. But these methods have problems such as low sensitivity, high cost and a long time. One of the ways in which scientists have considered the catalytic hydrogenation of these materials in recent year is to convert nitrophenol into aminophenol derivative by making heterogeneous nanocatalyst, toxic substances and carcinogens of nitrophenol. In this paper, Copper complex was synthesized by three dentate Schiff base ligands (ONO) with the general structure of [CuL(DMF)] which L is 1-((2-amino-nitrophenylimino) methyl) naphthalene and characterized by FT-IR Spectroscopy. Then [CuL(DMF)]/KIT-5, and [CuL]/ KIT-5/PPh3 catalysts were prepared from synthesized complex, mesoporous silica KIT-5 and phosphine and characterized by FT-IR, XRD and FE-SEM methods. Afterwards, their catalytic activity in the reduction of para and ortho-nitrophenol to para and to ortho-aminophenol was followed via UV-Vis spectroscopy and their recyclability were investigated. The results showed that [CuL]/KIT-5/PPh3 catalysts possess a higher efficiency in para and ortho-nitrophenol reduction respectively.

In this study the formation of charge transfer complexes between porphyrin free bases such as tetraphenyl porphyrin (TPP) and tetrakis (4-methylphenyl) porphyrin (Me-TPP) as electron donors (D) with some electron acceptors (A) such as 2, 4, and 6-trinitrophenol (Picric acid) and 1-Chloro-2, 4 and 6-trititrobenzene (picryl chloride) were investigated using UV-Vis spectrophotometry in dichloromethane at 293-308K. The porphyrin peak decreased at 418-419 nm and two new absorption bands developed at 441-448 and 654-667 nm. These new bands were characteristic of the charge transfer from HOMO of porphyrin to the LUMO of electron acceptor. The isosbestic point characterized the existence of one equilibrium and two adsorbent species. The Benesi-Hildebrand equation was applied to calculate the equilibrium constants and molar absorption coefficients of the complexes at different temperatures. With considering the temperature dependence of the complex formations, the Vant Hoff equation was used to calculate the thermodynamic constants of the complex formation reactions (ΔH, ΔG, ΔS). The is no deviation linearity at the Vant Hoff equation for all the complexes in different temperatures represented a 1: 1 complex formed between acceptor and donor.

In this research, Pd nanoparticles were synthesized in ethane-benzene periodic mesoporous organosilica and their catalytic activity was investigated in the Suzuki-Miyaura reaction. The synthesized nanocatalyst was studied by several analyzes such as nitrogen adsorption-desorption analysis, field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDX) and inductively coupled plasma analysis (ICP). Then the activity of the obtained nanocatalyst was investigated in the Suzuki-Miura coupling process. The final optimum conditions for the Suzuki coupling reaction are: aryl boronic acid (1.1 mmol), aryl halide (1 mmol), potassium carbonate (3 mmol), nanocatalyst (0.2 mole%), ethanol as solvent and temperature 65 ˚C. The results indicate that this nanocatalyst has high activity in the production of biaryl product. In addition, the recycling experiment showed that no considerable change in the activity of the catalyst for at least 6 consecutive runs, which clearly demonstrates the stability of the catalyst for these conditions in the Suzuki-Miyaura reaction.

The aim of this study is the investigation of photocatalytic degradation Doxycycline antibiotic in aqueous solution using different ZnO particles (Aldrich nanoparticles, Merck microparticles and synthesized nanoparticles via chemical deposition) immobilized on glass under UV-C light irradiation. Characteristics of the glass plates coated with ZnO particles were investigated by SEM, AFM and XRD technics. The influence of operational parameters (initinal concentration of doxycycline, UV light intensity and pH value) on activity of ZnO photocatalyst and the kinetic of reaction has been investigated. The results showed that ZnO was effective for the degradation of doxycycline from aqueous solutions in the presence of UV-C light. Removal Percent of 75 mg L-1 of doxycycline, in light intensity = 40 W m-2 and pH = 6.5, for 4 h was found 45.2, 48.80 and 52.7% for Aldrich, Merck and synthesized ZnO respectively. Results of mineralization studies also showed a decreasing trend of COD over time. The results showed that the reaction follows pseudo-first-order kinetic.

Abstract Inquiry-based education is one of the most innovative teaching methods that are very popular in educational systems all over the world. One of the benefits of this approach is to reinforce the questioning spirit of the students and enabling them to analyze scientific issues through their individual abilities and enhancing team working between them. In order to implement this method, in the Special Topics in Chemistry course at Isfahan University, it was decided to teach the basic concepts of spectroscopy by building a simple optical spectrometer. In this regard, in addition to recording the absorption spectra of different solutions in the visible area using a fabricated device, the effects of different radiation sources and dispersive elements were also investigated. The absorption spectrum of potassium permanganate solution was used to adjust the wavelength of the spectrometer to the actual wavelength. The various stages of making this device led to the recognition of different parts of optical spectrometers and motivated students to deepen their understanding of the concepts. The purpose of this method is to introduce students as next-generation chemistry teachers and to apply this method in the traditional Iranian educational system. Finally, this approach was used to write this article by all students as a group effort to know how to write and submit a scientific article.