نشریه شیمی کاربردی روز
پیاپی 49 (زمستان 1397)

An electrochemical sensor based on deposition of polymeric film by using electrochemical method on the surface of glassy carbon electrode was fabricated for simultaneous determination of dihydroxybenzene using differential pulse voltammetry (DPV). The sensor was constructed by simple modification of glassy carbon electrode (GCE) with a uniform electro-polymerized film of poly (eriochrome black T) (poly(EBT)). The electro-chemical behaviors of hydroquinone (HQ), catechol (CC) and resorcinol (RS) at the modified electrode were studied. The obtained peak current was linearly dependent on the HQ, CC, and RS concentrations in the range of 0.50-70.0 µM, 0.50-70.0 µM and 1.0-70.0 µM, respectively. The detection limits for HQ, CC and RS at the surface of poly(EBT)/GCE were 0.20 µM, 0.11 µM and 0.60 µM (3σ), respectively. In addition, simultaneous determination of dihydroxybenzene was evaluated in real sample of water with differential pulse voltammetry.

Seeds are coated widely with different polymers for increasing productivity and improving stand establishment of different crops. Emulsion copolymerization of vinyl acetate and butyl acrylate can be used for sugar beet seed coating. In this study, for the first time, a fractional factorial design, as an statistical experimental design method, was combined with image analysis method to achieve the optimal condition for emulsion copolymerization of vinyl acetate (VAc) and butyl acrylate (BuA) as a delayed-germination copolymer. The optimum condition was on the time of 3.16 hours, the temperature of 65˚C, the initiator concentration and anionic surfactant of 0.0121 wt%.The synthesized copolymer was homogeneous and was characterized using ATR-Fourier transform infrared spectroscopy (ATR-FTIR), Differential Scanning Calorimetry (DSC), Particle Size Distribution (PSD) and Scanning Electron Microscope (SEM) analysis. Then the synthesized copolymer was used for coating of sugar beet seeds. The results show that the synthesized copolymer does not have adverse interaction with pesticides, fungicides and the color, which used for seed coating. Therefore, it can be used in coating of sugar beet seeds. Also, the synthesized copolymer delayed germination about 40 days.

In this investigation, we have reported the synthesis of the complex [Th(5,5´-dmbpy)3](NO3)4](1) that 5,5´-dmbpy =5,5´-dimethyl-2,2´-bipyridine. This complex has been characterized using spectral methods (FT-IR, UV-Vis, 1H-NMR and luminescence), elemental analysis and the Cyclic Voltammetry (CV) method. The FT-IR data shows that 5,5´-dimethyl-2,2´-bipyridine (5, 5´- dmbpy) ligand adduct to metal centers by nitrogen atoms. Electronic spectra of (1) shows ligand field transitions and charge transfer (CT) bands. Electrochemical data for the complex in the DMF solution show reduction and oxidation processes for the Thorium ion and ligand. The interactions of complex (1) with FS-DNA have been investigated using UV–Vis and gel electrophoresis. The binding constant (Kb) was calculated using UV–Vis technique (Kb=3.5×105). Also, DNA cleavage was studied using agarose gel electrophoresis. The antibacterial properties and fluorescence property of complex (1) have also been examined. The in vitro biological screening effects of the complex and ligand were tested against different types of bacterium and [Th(5,5´-dmbpy)3](NO3)4](1) shows antibacterial properties.

In this study, ZnO-Cr2O3/epoxy nanocomposites are employed to protect mild steel corrosion in 3.5% NaCl solution. The corrosion performances of the nanocomposites coatings were evaluated by using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Electrochemical measurements show that ZnO-Cr2O3 nanocomposite coated has good inhibitive properties with PE% of ~99% at 0.04 gr/L concentration on mild steel corrosion in 3.5% NaCl solution. The results indicated that the incorporation of ZnO-Cr2O3 nanoparticle into epoxy resin coating significantly decrease the corrosion current as well as the hardness of epoxy coatings. ZnO-Cr2O3 nanoparticle are able to cure the defect in epoxy resin and prevent the diffusion of corrosive electrolyte to mild steel substrate.

In this work, Ni nano structures with different surface morphology have been electrodeposited from the Waths bath using direct current (DC) and pulsed reverse current (PRC) techniques in the presence of three types of surfactants. CTAB, SDS, and Triton x-100 have been used as cathionic, anionic and nonionic surfactants respectively. The surfactants concentration have been selected at below, equal to and above the corresponding critical micelle concentration (CMC). The SEM analyses show that the porosity and homogeneity of the electrodeposited samples depend on the surfactant type and its concentration. In the presence of CTAB, electrodeposition process has been certainly hindered in some region. For SDS, nano-particles with the same charges repel each other and disperse in a more uniform way. In the presence of Triton x-100, agglomeration of particles is seen and particles are not dispersed. The corrosion behavior of electrodeposited samples has also been investigated in 1 M NaOH solution using Tafel potentiodynamic polarization method as well as electrochemical impedance spectroscopy analyses. It is observed that all samples have low corrosion current density and the sample prepared above the CMC point of SDS has the lowest corrosion rate. In addition, according to our findings, the electrodeposited samples using DC method have larger particle sizes and lower corrosion rate.

In this study, three-component nanoparticles of iron, nickel and lithium were synthesized with two methods of combined technique (co-precipitation, hydrothermal) and pechini sol-gel. The optimum conditions for producing magnetic nanoparticles (MNPs) by co-precipitation method were found to be at pH=13 with constant stirring rate of 1000 rpm and at temperature of 72 ˚C under nitrogen atmosphere. The situation for preparing nanoparticles by pechini sol-gel method including dissolving nitrate salt of three metals in water then adding citric acid and ethylene glycol respectively in temperatures 60 and 80 0 C with pH=7 and placing sample in temperatures 190 and 500 0 C for 720 and 60 minutes respectively. In the comparison of two methods, morphology and size of produced magnetic nanoparticles with combined method of co-precipitation- hydrothermal was more suitable. Response surface methodology was used to verify the best synthesized nanoparticles in size. The surface of MNPs was modified with silica and amine groups to develop a suitable drug delivery system.

Poly(methyl methacrylate-co-nitrophenyl maleimide) (MMA-co-NMI) and poly(methyl methacrylate-co-hydroxyphenyl maleimide) (MMA-co-HMI) copolymers were synthesized using free radical polymerization of MMA with a new MI monomer containing phenyl and –NO2 groups. Proton exchange membrane fuel cell(PEMFC) were prepared using these copolymers as membrane matrix and phosphotungstic acid (PWA) as proton conductive additive. Dry-phase inversion method was employed to fabricate membranes with different concentrations of copolymers and PWA. Characteristics and proton conductivity of membranes were investigated using FTIR, SEM, TGA, DTG, DSC, ion exchange capacity, water uptake, and proton conductivity tests. Results revealed an increment in the thermal stability as well as ion exchange capacity of composite membranes prepared by addition of PWA. Moreover, applying MMA-co-HMI as copolymer and PWA as additive remarkably improved the proton conductivity of membrane (2.6×10−1 S.cm−1) due to the interaction between the functional groups of PWA (H3O+ ions, O atoms) and MMA-co-HMI copolymer (OH, C=O functional groups).

In this paper, the voltammetric properties of entacapone, an anti-Parkinson’s disease drug, were investigated by cyclic voltammetry and differential pulse voltammetry at MWCNTs modified carbon paste electrode in phosphate buffer in presence of Tween 20 and validated for quantitative determination of entacapone in bulk, pharmaceutical dosage forms and human plasma. Several factors such as pH, type of surfactant and scan rate were investigated in order to study the optimum conditions for determination of entacapone. A good linear relationship was obtained within the concentration range from 50 ˟ 10-9 to 2.4˟10-3M. The limits of detection and limit of quantification were found to be 8×10-10and 2.4×10-9molL-1, respectively. The proposed method was simple, rapid and economic, so it is suitable for routine analysis of entacapone in pure form and dosage forms and for pharmaco kinetic studies.

In this research, a cadmium(II) nano coordination compound, [Cd(dmph)I2] (1), {dmph= 2,9-dimethyl-1,10-phenanthroline (neocuproine)}, was synthesized by sonochemical method from cadmium(II) acetate, KI and the neocuproine ligand. The nano-structure (1) was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), elemental analyses and IR spectroscopy. The compound 1 was structurally characterized by single crystal X-ray diffraction and showed that Cd(II) ion is four-coordinated in a distorted tetrahedral configuration with two N atoms from a neocuproine ligand and two terminal iodine atoms. The thermal stability of compound 1 both in its bulk form and nano-size form had been studied by thermal gravimetric (TG) and differential thermal analyses (DTA) for comparsion with each other. Pure phase CdO and CdI2 nanoparticles were prepared by calcination of compound 1 at 700 °C under air atmosphere and hydrothermal processing from the same compound at 150 °C for 48 h, respectively. The morphology and phase of the prepared samples were further studied using SEM and XRD. The sonochemical method resulted in a significant reduction of reaction time, reaction temperature and particle sizes of the products.

In the present work a new Schiff base ligand was prepared by condensation of 4-hydroxy-3-methoxybenzaldehyde with DL-1-phenylethylamine (HL1). The product was characterized using FT-IR, 1H-NMR, and UV-Vis spectroscopy. The structure of HL1 Schiff base ligand was determined by X-ray crystallography. According to this analysis, HL1 ligand is crystallized in the orthorhombic crystal structure with space group Pbca. Also, the structure and electronic properties of HL2 Schiff base ligand which was synthesized before and HL1 ligand were analyzed by using DFT calculations. The docking analysis of ligands was reported that bind to the minor and major grooves of B-DNA sequence, respectively.