نشریه شیمی کاربردی روز
پیاپی 59 (تابستان 1400)

In the present research work, at first, the preparation of cobalt oxide nanoparticles was done by sol–gel auto-combustion method. The characteristic properties of the powder were done by techniques of XRD, FT-IR, AFM and FESEM techniques, which revealed the structural, functional groups and particle size and morphology of the sample, respectively. X-ray diffraction show formation of the Co3O4 nanoparticles with spinel structure. The average crystallite size of the sample was obtained 5-10 nm by using the Scherrer formula, respectively. FT-IR spectrum confirm the formation of cobalt oxide bonds. FESEM images show that the shape and size of nanoparticles produced by a sol – gel were 20-50 nm with a cuboid particle shape. After preparation of cobalt oxide nanoparticles, we used them to produce super-hydrophobic surface. The produced cobaltite nanoparticles were coated on the glass substrate and then put in the furnace. In the end, Palmitic acid and Acetic acid as samples of organic acids were applied for modification of coating.. Different ratio of the acides were used to prepare the coating. The best super hydrophobic coating was resulted for the coating modified with the 1:1 ration of palmetic acid and acetic acid. The value of contact angle (CA) for the water droplet on the surface of best coating was 158.2, indicating that the coating exhibit the super-hydrophobicity property. The self-cleaning property of the coating was tested by dispersing of mud on it for 48 h and after that no mud adhesive on the coating, indicating the self-cleaning properties of the modified cobaltite coating.

In this study, the concentration of effective amino acids in plant metabolism was measured in different soil and fertilizer samples by high performance liquid chromatography. First, the amino acids of the sample were extracted with 0.1 N hydrochloric acid. Then they were derivatized with phenyl isothiocyanate (PITC). Finally, the phenylthiocarbamyl-amino acid derivatives were isolated in the reverse phase column using gradient elution with sodium acetate trihydrate and acetonitrile-water (40:60), and detected by a UV detector at 254 nm. Several parameters related to the separation of amino acid peaks, including pH and temperature of the mobile phase, buffer concentration and modifier (triethylamine) in the mobile phase were studied. By changing each of the existing conditions, the amount of resolution for amino acid peaks was optimized. Under optimal conditions, a good linear range (0.0312-0.125 µmol / ml) was obtained for 17 amino acids with a detection limit of 0.0094 µmol / ml and acceptable reproducibility for each amino acid (RSD ≤6.1%). Finally, the percentage of free amino acids was measured in different soil and fertilizer samples by this method.

In this research a novel four-coordinated silver(I) complex with N-donor chelating ligands with formula [Ag(L1)(L2)]NO3, (where 4,5-diazafluoren-9-one = L1 and N-(4,5-diazafluoren-9-ylidene)aniline = L2) has been prepared and characterized with spectroscopic methods (UV-Vis, FT-IR and 1HNMR), elemental analysis, and molar conductivity measurement. The DNA-complex binding mode has been investigated by electronic absorption titration, luminescence titration, and thermodynamic studies and the relationship between the structure and the biological properties has been discussed. The binding constants (Kb) and thermodynamic parameters (enthalpy, entropy, and Gibbs free energy changes) have been calculated. The theoretical studies of the complex structure in the DFT framework have predicted the tetrahedral N4 coordination geometry for Ag(I) center. The molecular docking has been carried out to determine the binding mode and the best orientation of the complex with DNA. The experimental and theoretical results reveal that the Ag(I) complex binds to CT-DNA with a moderate intercalation capability with the partial insertion of the planar ligands between the double-stranded DNA bases and binding constant of 1.66×105 M-1.

In this survey, the Ni-W/SiO2 nanocomposite coatings were synthesized via electrodeposion method and in the solution with the different concentrations of SiO2 nanoparticles by the average current density of 20mA/cm2. Then, field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive Spectroscopy (EDS) were used to analyze the morphology and chemical composition of the coatings. In order to evaluate the corrosion behavior of the coatings, the open circuit potential (OCP), electrochemical Impedance (EIS) and potentiodynamic polarization (Tafel) tests were applied in 3.5% NaCl solution. The corrosion results demonstrated that the corrosion resistances of Ni-W/SiO2 nanocomposite coatings were higher compared to pure Ni-W coating so that the highest value of charge transfer resistance was obtained for Ni-W/SiO2 coating electrodeposited from solution with concentration of 6 g/L SiO2 nanoparticles. The co-deposition of maximum amount of reinforced particles in the matrix and the microstructure without any micro tracks and surface defects are the main reasons for the improvement of electrochemical behavior of this coating.

In this paper, the effect of CTAB and Triton X-100 surfactants as nickel corrosion inhibitors in alkaline solution at three temperatures of 25, 40, and 60 0C was investigated. The Tafel polarization method was used to determine the corrosion potential, corrosion current intensity, and anodic and cathodic Tafel slopes. The inhibition performance of these two surfactants was studied separately and also in the form of a mixture of these two surfactants with different ratios. The results showed that in all three temperatures, by adding the surfactant to the medium, the nickel corrosion rate was reduced. The obtained optimum concentration for CTAB and Triton X-100 was 150 ppm and 200 ppm, respectively. The results of the adsorption isotherms showed that the adsorption of CTAB and Triton X-100 followed the Langmuir model. The synergistic effect of these two surfactants was also investigated and results showed that when the mixture of the two surfactants was used the inhibition efficiency was increased significantly which indicated the better performance of the surfactants mixture for the protection of nickel.

Selection of an appropriate solvent is of interest in the pharmaceutical industry. In some case, a mixture of solvents has a more solubility than the pure solvents. A predictive model such as the UNIFAC model can be employed to predict the solubility to reduce the cost of tests. However, the accuracy of the UNIFAC model should be evaluated to ensure the results of this model. In this work, the accuracy of the UNIFAC model is studied in predicting the solubility of 4-aminobenzoic acid in the binary mixtures of methanol, ethanol, acetone, and water. First, the UNIFAC model is used to predict the solubility of 4-aminobenzoic acid in the binary mixtures and then the binary mixtures whose solubility are high are selected to measure their solubility of 4-aminobenzoic acid and to compare with the results of the model. The experimental data showed that the solubility of 4-aminobenzoic acid in the binary mixtures of methanol-acetone (where the mole fraction of methanol is 0.65) and ethanol-acetone (where the mole fraction of ethanol is 0.2) is significantly higher than that of the pure solvents. However, the UNIFAC model predicted the maximum solubility of 4-aminobenzoic acid in methanol-acetone mixture where the mole fraction of methanol was 0.38 and, in the ethanol-acetone mixture where the mole fraction of ethanol was 0.3. Thus, the UNIFAC model can be used for an initial estimation of the maximum solubility in the mixtures; however, this model is not precise model for accurate prediction of the solubility of 4-aminobenzoic acid.

In this research, the 1, 2-bis(4-pyridylthio)ethane (PTE) functionalized grapheme oxide is used as powerful support for immobilization of cobalt complex to deliver a novel heterogeneous catalyst (Co-PTE-GO) for epoxidation of alkenes. The Co-PTE-GO catalyst was characterized by different techniques such as Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Raman spectroscopy and inductively coupled plasma optical emission spectrometry (ICP-OES). These analyses confirmed high chemical and thermal stability of the designed catalyst. The Co-PTE-GO was used for epoxidation of linear and cyclic alkenes giving corresponding epoxides in high yields (81-97%). This catalyst was recovered and reused at least 4 times with keeping its performance under reaction conditions.

Electrochemistry due suitable performance (selectivity, speed, sensitivity, and high accuracy) provides very interesting and versatile means for the study of pharmaceutical and biological compounds. In this study, electrochemical oxidation of clomipramine in the absence and presence of 1,3 dimethyl barbituric acid as a nucleophile in acidic medium with mechanistic studies has been investigated and synthesis a new dibenzazepine derivative electrochemically. Electrochemical oxidation of clomipramine drug has been studied in aqueous solution and various pHs using cyclic voltammetry and controlled-potential coulometry. Based on electrochemical results, dimerization is the main reaction of electro-oxidation of clomipramine in the absence of nucleophile via an ECE mechanism. Also, voltammetric results indicate that the oxidized dimeric form of clomipramine participation in Michael addition reaction with the1,3 dimethyl barbituric acid via an ECEC electrochemical mechanisms. However, the voltammetry and coulometry results imply existence of a catalytic (EC’) electrochemical mechanism in parallel with ECEC electrochemical mechanism. Finally, the product has been characterized by IR, 1H NMR, 13C NMR and MS methods

A novel kind of AgNPs-MWCNTs/TiO2 nanotubes/Ti electrocatalyst for the electrocatalytic oxidation of glycerol was fabricated via electrodeposition of Ag nanoparticles and functionalized multi walled carbon nanotubes on previously formed TiO2 nanotubes/Ti electrode. The morphology studies showed that AgNPs-MWCNTs nanocomposites have dendritic structures, where Ag nanoparticles are uniformly dispersed on the surface of MWCNTs. Electrochemical investigation exhibited that the AgNPs-MWCNTs/TiO2NTs/Ti show much higher peak current density and lower charge transfer resistance towards the glycerol oxidation than AgNPs/TiO2NTs/Ti electrode, indicating good electrocatalytic performance and kinetic reversibility of the AgNPs-MWCNTs/TiO2NTs/Ti electrocatalysts. The improved electrocatalytic activity of modified electrode is originated from the synergetic effect of AgNPs-MWCNTs, the unique nanostructure and large surface area which can provide more active sites to catalyze the glycerol oxidation.

The purpose of this study was to develop zeolitic imidazolate frameworks (ZIFs) incorporated with poorly water-soluble drug fenofibrate (FEN), belonging to Biopharmaceutical Classification System (BCS) class II, to improve drug dissolution, intended to be orally administrated. FEN-loaded ZIF-8 were characterized with N2 adsorption-desorption analysis, fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), and dynamic light scattering (DLS) with the results demonstrating the successful incorporation of FEN into the ZIF-based host. Different parameters including similarity factor (f2), difference factor (f1), dissolution efficiency (DE%) and mean dissolution time (MDT) were employed to analyze drug release tests, confirming a significant enhancement in the release profile of FEN with ZIF-8 as drug dissolution enhancer. Compared to enzyme-free simulated intestinal fluid (SIF), remarkable dissolution enhancement of FEN was observed in enzyme-free simulated gastric fluid (SGF) as drug release media. Fitting the experimental data from the release studies to different kinetic models showed the best fitting with Weibull, First order with Fmax and Korsmeyer-Peppas models.

In the present study, three complexes with nickel central metal and with general formula [Ni(L)2]; where L is 3-hydroxy flavone (HLf), deferiprone (HLd) and maltol (HLm); synthesized and characterized by Infrared spectroscopy, mass spectroscopy, and elemental analysis. Studies have shown three ligands that used in this study, after coordination to metals, prevent the proliferation of cancer cells, so the anti-cancer property of the synthesized compounds was investigated by MTT assay against HeLa, MCF-7, MDA-MB-231, NALM-6, Neuro-2a, and L929; cell lines and cisplatin was used as a control. Furthermore, we investigate the ability of 3-hydroxy flavone (HLf), deferiprone (HLd) and maltol (HLm) chelating with nickel (II) metal ion using density functional theory in both gas and solvent phases, Through the M062x/6-311++G(d, P) surface and Gaussian09 calculation package. Structural analysis shows that all three chelators are bonded to Ni2+ via oxygen atoms of hydroxyl, and carbonyl groups. The receptor-acceptor interactions represent the effective charge transfer from the oxygen atoms of the chelators to the metal ions. The quantum theory of atoms in molecular analysis reveals noncovalent interactions, and it should be noted that mainly, electrostatic interactions play an important role in the formation of Ni-metal complexes. The TD-DFT study was performed to investigate the main electron transfer. ELF and LOL analyzes were also performed to confirm the results obtained through QTAIM analysis. Interaction energies and metal ion affinity were calculated for [Ni(L)2] complexes, and the results showed that we observed a very exothermic reaction during the chelating process. Natural bond analysis (NBO) was performed to understand the charge transfer in the studied complexes. The results confirmed that the selected chelators are suitable chelating agents for the treatment of nickel.

Silica is a valuable compound with very high performance in various fields. The aim of this study was to investigate the sites of silica accumulation in corn to prepare SBA-15 and its use in the removal of chromium and fluoride from aqueous solutions. First silica nanoparticles and then functionalized SBA-15 nanoparticles were synthesized. Afterwards the effect of pH, adsorbent amount, initial concentration of ions and contact time on the removal of heavy metals chromium and fluoride were tested. To measure the samples, colorimetric method was performed using spectrophotometers at 540 and 570 nm. The amount of silica in corn was determined using X-ray fluorescence (XRF). The results showed that the highest percentage of silica was related to corn leaves with 93.8%. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) indicated the formation of silica particles with amorphous structure and siloxane bonds (Si-O-Si). The results of scanning electron microscopy (SEM) represented a size of about 8-15 nm. Transmission electron microscopy (TEM) images displayed that the SBA-15 has been successfully synthesized with hexagonal symmetry and regular channels, a large pore volume, and an average pore diameter of 10 nm. The results pointed that the maximum adsorption time for chromium was 60 min and in 80 min for fluorine. The amount of adsorption per adsorbent unit increased by 53% for chromium and by 41% for fluorine. This study demonstrated that corn agricultural waste can be a good source for the production of silica and SBA-15 nanoparticles, which can also be effective as a cheap and useful way to eliminate water pollution.

Molecular imprinted polymer (MIP) technology is a highly efficient method of separating impurities and enhancing the quality and purity of pharmaceutical and food raw materials because of its advantages such as high selectivity, chemical stability and low cost. In the present study, theMIP as a selective adsorbent on the target molecule was synthesized by free-radical polymerization, mass and noncovalent methods. In this polymer, methacrylic acid (monomeric agent), -N', N'Methylene-bis-acrylamide(MBAAm) (crosslinking agent), ammonium persulfate (initiator), inulin (target molecule) and water (solvent) were used. To compare the polymer performance, a not-imprinted polymer(NIP) was synthesized under the same conditions without the use of the target molecule. The structure of the synthesized polymers was confirmed by Fourier transform infrared(FT-IR) spectroscopy. The polymer porosity was calculated to be 43.4%. The selectivity of the MIP for adsorption of the target molecule was investigated through adsorption experiments and its results were compared with the adsorption of the target molecule by NIP. Moreover, various parameters such as pH, time, sample concentration and ionic strength were optimized. The results of the experiments showed that at pH = 4 after 15 minutes the amount of inulin uptake will be 137.142.