فاطمه مستغنی

In this research, a new and environmentally friendly chemical sensor was introduced using Bromopyrogallol red (BPR) to determine trace amounts of aluminum and fluoride ions in dimethyl sulfoxide/water (5.5, v/v) solvent. The results showed that the color of BPR changes from red to violet under the influence of visible light in the presence of aluminum ions. This chemical sensor can selectively detect aluminum with a detection limit 2.21×10-7 and quantitation limit 7.37×10-7 mol L−1. Upon addition of aluminum ion, the absorbance signal of [Al-BPR] increased linearly in the concentration range of 1.60×10−6 - 8.06×10−5 mol L−1. In addition, [Al–BPR] complex can be used for the determination of F-. The signal of [Al-BPR] upon addition of F- decreased linearly in the concentration range of 4.0×10-5 - 8.80×10-4 -. The relative standard deviation (RSD) for 5 times of measurement (n=5) in two concentrations of 1.87×10-5 and 3.07×10-5 mol L−1 of aluminum are 2.9% and 2.1% respectively. To determine the stoichiometry of the reaction between BPR receptor and aluminum ion, the molar ratio method was used. According to the experiments, this ratio was determined to be 1:1. BPR can also be used to detect aluminum ions in different water samples with high recovery percentage.

In this work, the linear and nonlinear optical properties of the Schiff base N,N'-bis(2-hydroxybenzylidene) benzidine (HBB) will be investigated by two methods, Z-scan technique and quantum mechanical calculations. For this purpose, first, the absorption spectrum of HBB compound in DMSO, DMF, CH3Cl is prepared and the effect of solvent polarity on their bandgap energy is investigated. The results show that the dissolved sample in DMSO has better nonlinear properties than other samples. Then, the nonlinear properties of the sample are calculated by the Z-scan technique. The values of the nonlinear refractive index, nonlinear absorption coefficient and third order susceptibility of the sample in DMSO solvent are 0.10810-10 cm2/W, 0.1436110-6 cm/W and 4.43710-9 esu respectively. Also, the quantum mechanical analysis will be used for calculating the dipole moment (), the dipole polarizability (), and also the second and third nonlinear molecular hyperpolarizabilities (β and γ). Both experimental and theoretical results show that the HBB has a high nonlinear potential and can be a good candidate for optical devices.

In this study, 1- (2-ethoxyphenyl) -3- (4-nitrophenyl) triazene (ENT) as a compound with high nonlinear optical properties for application in optical devises has been studied. For this purpose, linear and nonlinear optical properties of asymmetric diaryl triazene with electron acceptor and donor subsituents are investigated. Initially 1- (2-ethoxyphenyl) -3- (4-nitrophenyl) triazene (ENT) was synthesized and its structure and properties were identified by melting point, IR and HNMR spectroscopy. Then the UV-Vis spectrum of the compound was prepared and band gap energy (2.4 eV) was calculated using the Tauc equation. In addition, the natural bond orbital (NBO) calculations, frontier molecular orbitals, dipolemoment moment, second and third order hyperpolarizability and anisotropy (Δ α) were calculated using density functional theory (DFT) calculation with 6-31G++(d,p) basis set. frontier molecular orbital studies and band gap energy calculations, high amounts of dipolemoment and high polarizability as well as the results of intramolecular electron transfer (ICT) obtained from NBO calculations indicated ENT molecule has high ICT and may have potential applications in the development of NLO materials and optical devises.

This paper is focused essentially on the synthesis and morphological investigation of CoFe2O4 nanoparticles in the field of medicine and targeted drug delivery. Therefore, the magnetic nanoparticles for this field require not only optimistic magnetic properties and narrow size distribution but also to be non-toxic and biocompability. Biological synthesis method is suitable for this purpose. The magnetite nanoparticles CoFe2O4 is synthesized using co precipitation method from metal salts and pistachio leaf extract at low temperature and ambient pressure. The synthesized magnetite nanoparticles were characterized by X-ray diffraction and Rietveld analysis. XRD pattern, confirmed the single phase formation of pure CoFe2O4 and without any impurity phase with 14 nm of average diameter. Rietveld analysis, confirmed the expected cubic inverse spinel structure with Fd3m space group and good properties. The method in the present study offers several important advantageous features. First, the synthesis method is economical and environmentally friendly, because it involves inexpensive and non-toxic materials. Second, size-controlled CoFe2O4 nanoparticles are produced easily in one pot rate. In addition, carboxylate ions in leaf extract act as shielding agent which induce the stability of the biologically synthesized nanoparticles.

In this study، optical behavior of methylated and unmethylated Bjorkman lignin from populus wood and two lignin model compounds (phenolic and non phenolic) with β-O-4 linkages after transferring on a cellulosic matrice (Whatman Paper) was investigated in different times (0، 5، 10، 15، 20 h). Then paper surface was analyzed using Attenuated Total Reflectance (FTIR) thecnique. The results showed that irradiation altered the chemical structure of all samples. Lignin was the most sensitive component to photodegradation and the intensities of its characteristic bands decreased significantly during the process of irradiation. This was accompanied by formation of new carbonyl groups appearing at 1735 cm_1. Compared with the unmethylated forms، the rate of lignin degradation and carbonyl formation was relatively lower in methylated forms. In other words، methylation of phenolic hydroxyl group reduced the chemical changes induced by irradiation.