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101.
102.
Ali Hossein Kianfar Sanam Asl Khademi Roghaye Hashemi Fath Mahmoud Roushani Mojtaba Shamsipur 《Journal of the Iranian Chemical Society》2013,10(2):347-355
The VO(IV) complexes of tridentate ONN Schiff ligands were synthesized and characterized by IR, UV–Vis and elemental analysis. The electrochemical properties of the vanadyl complexes were investigated by cyclic voltammetry. A good correlation was observed between the oxidation potentials and the electron-withdrawing character of the substituents on the Schiff base ligands, showing the following trend: MeO < H < Br < NO2. The thermogravimetry (TG) and differential thermoanalysis (DTA) of the VO(IV) complexes were carried out in the range of 20–700 °C. The VOL1(OH2) and VOL2(OH2) decomposed in three steps, whereas the VOL3(OH2) and VOL4(OH2) complexes decomposed in two steps. The thermal decomposition of these complexes is closely related to the nature of the Schiff base ligands and proceeds via first-order kinetics. The structures of compounds were determined by ab initio calculations. The optimized molecular geometry and atomic charges were calculated using MP2 method with 6-31G(d) basis. The results suggested that, in the complexes, V(IV) ion is in square-pyramid N2O3 coordination geometry. Also the bond lengths and angles were studied and compared. 相似文献
103.
Mahmoud Reza Sohrabi Zahra Matbouie Ali Akbar Asgharinezhad Ali Dehghani 《Mikrochimica acta》2013,180(7-8):589-597
We describe a novel magnetic metal-organic framework (MOF) for the preconcentration of Cd(II) and Pb(II) ions. The MOF was prepared from the Fe3O4-pyridine conjugate and the copper(II) complex of trimesic acid. The MOF was characterized by IR spectroscopy, elemental analysis, SEM and XRD. A Box-Behnken design through response surface methodology and experimental design was used to identify the optimal parameters for preconcentration. Extraction time, amount of magnetic MOF and pH value were found to be critical factors for uptake, while type, volume, concentration of eluent, and elution time are critical in the elution step. The ions were then determined by FAAS. The limits of detection are 0.2 and 1.1 μg?L?1 for Cd(II), and Pb(II) ions, respectively, relative standard deviations are <4.5% (for five replicates at 50 μg?L?1 of Cd(II) and Pb(II) ions), and the enrichment capacity of the MOF is at around 190 mg?g?1 for both ions which is higher than the conventional Fe3O4-pyridine material. The magnetic MOF was successfully applied to the rapid extraction of trace quantities of Cd(II) and Pb(II) ions in fish, sediment, and water samples. Figure
Schematic illustration of synthesized magnetic MOF-pyridine nanocomposite 相似文献
104.
Mohamed R. Mahmoud Hussein S. Elkashef Maher M. Ahmed 《Monatshefte für Chemie / Chemical Monthly》1980,111(5):1213-1224
The electronic absorption spectra of some 2-styryl-4-phenyl-thiazole ethiodides are studied in organic solvents of different polarities. The shorter wavelength band appearing in the visible region is assigned to an intramolecular charge transfer (CT)-transition originating from the phenyl moiety to the positively charged hetero ring, while the longer wavelength one is due to an intermolecular CT-transition from the iodide ion to the 2-styryl-4-phenyl-thiazolinium cation. These assignments are based on the nature of the aldehydic residue and effects of solvent, concentration, and temperature on both the position and absorptivity of the CT complex-band. It is concluded that the CT complex formed will be highly solvated inDMF, DMSO, ethanol and methanol relative to in CHCl3, dioxane and acetone. The formation constant of the CT complex in solutions of different polarities is determined at different temperatures. Furthermore, the thermodynamic parameters H
o, G
o and S
o for complex formation are calculated and discussed.
Absorptionsspektren von 2-Styryl-4-phenyl-thiazol-ethiodiden in verschiedenen Lösungsmitteln und Bestimmung der Bildungskonstanten der Charge-Transfer-Komplexe
Zusammenfassung Die Elektronenanregungsspektren einiger substituierter 2-Styryl-4-phenyl-thiazol-ethiodide wurden in einigen Lösungsmitteln unterschiedlicher Polarität untersucht. Die Absorption bei kürzerer Wellenlänge wird einem intramolekularen Charge-Transfer (CT)-Übergang zugeordnet, die langwellige Bande einem intermolekularen CT-Übergang (Jodid—organ. Kation). Die Diskussion erfolgt basierend auf Substitutions-, Lösungsmittel-, Konzentrations-, und Temperatur-Effekten. Die Komplexbildungskonstanten und die thermodynamischen Parameter H o, G o und S o werden angegeben.相似文献
105.
Mahmoud Emam Doaa R. Abdel-Haleem Maha M. Salem Lina Jamil M. Abdel-Hafez Rasha R. Abdel Latif Shaimaa Mahmoud Farag Mansour Sobeh Mohamed A. El Raey 《Molecules (Basel, Switzerland)》2021,26(6)
Infections associated with the emergence of multidrug resistance and mosquito-borne diseases have resulted in serious crises associated with high mortality and left behind a huge socioeconomic burden. The chemical investigation of Lavandula coronopifolia aerial parts extract using HPLC–MS/MS led to the tentative identification of 46 compounds belonging to phenolic acids, flavonoids and their glycosides, and biflavonoids. The extract displayed larvicidal activity against Culex pipiens larvae (LC50 = 29.08 µg/mL at 72 h). It significantly inhibited cytochrome P-450 monooxygenase (CYP450), acetylcholinesterase (AChE), and carboxylesterase (CarE) enzymes with the comparable pattern to the control group, which could explain the mode of larvae toxification. The extract also inhibited the biofilm formation of Pseudomonas aeruginosa by 17–38% at different Minimum Inhibitory Concentrations (MICs) (0.5–0.125 mg/mL) while the activity was doubled when combined with ciprofloxacin (ratio = 1:1 v:v). In conclusion, the wild plant, L. coronopifolia, can be considered a promising natural source against resistant bacteria and infectious carriers. 相似文献
106.
Amira Mahmoud Mosaab Echabaane Karim Omri Julien Boudon Lucien Saviot Nadine Millot Rafik Ben Chaabane 《Molecules (Basel, Switzerland)》2021,26(4)
Copper-doped zinc oxide nanoparticles (NPs) CuxZn1−xO (x = 0, 0.01, 0.02, 0.03, and 0.04) were synthesized via a sol-gel process and used as an active electrode material to fabricate a non-enzymatic electrochemical sensor for the detection of glucose. Their structure, composition, and chemical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) and Raman spectroscopies, and zeta potential measurements. The electrochemical characterization of the sensors was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Cu doping was shown to improve the electrocatalytic activity for the oxidation of glucose, which resulted from the accelerated electron transfer and greatly improved electrochemical conductivity. The experimental conditions for the detection of glucose were optimized: a linear dependence between the glucose concentration and current intensity was established in the range from 1 nM to 100 μM with a limit of detection of 0.7 nM. The proposed sensor exhibited high selectivity for glucose in the presence of various interfering species. The developed sensor was also successfully tested for the detection of glucose in human serum samples. 相似文献
107.
A series of binary complexes of Zn(II), Hg(II), Pb(II), La(III), Ce(III), Th(IV) and UO2(II) with 3,5-dinitrosalicylic acid and 5-sulphosalicylic acid have been isolated and characterized. The solution equilibria of these complexes have been studied pH-metrically. The formation constants (log K) at 25±1°C and ionic strength of 0.2M NaClC4 have been calculated. Stability of the complexes formed in relation to ligand molecular structure and nature of the metal ion has been examined and discussed. 相似文献
108.
Ali Deeb Mahmoud Kotb Mohamed El-Abbasy 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2245-2252
3-Substituted pyrimido[4′,5′:4,5]thieno[2,3-c]pyridazine-2,4-di-ones and 3-amino-2-methylpyrimido[4′,5′:4,5]thieno[2,3-c]pyridazine-4-ones were synthesized starting from ethyl 5-aminothieno[2,3-c] pyridazine-6-carboxylate 1. Reaction of amino ester 1with phenyl isothiocyanate affords thiourea derivative 10which undergo further transformation to the related fused heterocyclic systems. 相似文献
109.
Al-Jaber HI Al-Qudah MA Barhoumi LM Abaza IF Afifi FU 《Natural product research》2012,26(13):1179-1187
The composition of the essential oil of fresh and air-dried Salvia palaestina Benth. (Lamiaceae) growing wild in Jordan has been studied using gas chromatography-mass spectrometry analysis. The essential oils of fresh and air-dried S. palaestina were mainly composed of sesquiterpene hydrocarbons (52.66% and 65.98%, respectively). The major component detected in the oils of fresh and dry S. palaestina was germacrene D (21.18% and 26.02%, respectively). Air drying resulted in a general increase of sesquiterpene hydrocarbons and a great decrease in the percentage of monoterpene hydrocarbons. 相似文献
110.
Khalid Mahmoud Hassan 《Journal of the Iranian Chemical Society》2018,15(5):1007-1014
A highly sensitive sensor based on Ni nanoparticles/poly (1,2-diaminoanthraquinone) modified electrode was fabricated at glassy carbon (GC) electrode (Ni/PDAAQ@GC ME) using cyclic voltammetry technique. The incorporation of nickel (II) ions nanoparticles (Ni NPs) followed by anodic polarization process was achieved. Surface morphologies of both PDAAQ@GC ME and Ni/PDAAQ@GC MEs were studied by scanning electron microscope. Ni/PDAAQ@GC ME was tested for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) by square wave voltammetry technique. The ME showed excellent electrocatalytic activity toward electrooxidation of these biomolecules in their single, binary and ternary systems in alkaline 0.1 M NaOH solutions. Experiment revealed that the low detection limits (LOD) for AA, DA and UA were 0.11, 0.072 and 1.2 µM in single system, respectively, and 0.069, 0.29 and 0.12 µM in ternary system, respectively. 相似文献