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211.
Laila H. Abdel-Rahman Lobna A. E. Nasser Ramadan M. Ramadan 《Transition Metal Chemistry》2007,32(3):367-373
A series of some new cobalt(II) and nickel(II) ternary complexes of N-(acetyl)phenylalaninate (acphe), N-(acetyl)tyrosinate (actyr), N-(benzoyl)leucinate (bzleu), N-(benzoyl)phenylalaninate (bzphe), N-(tosyl)glutamic acid (tsglu), N-(tosyl)arginine (tsarg) with certain N-heterocyclic ligands such as imidazole (imi), methylimidazole (mimi), 2,2′-bipyridyl (bipy) 1,10-phenanthroline (phen) have
been synthesized and characterized by elemental analyses, IR and electronic spectra. as well as thermogravimetry. The structure
of the cobalt(II) N-phthaloylglycinate complex was also characterized by X-ray single crystal. It was found that the cobalt atom coordinates
a 1,10-phenanthroline molecule and four water oxygen atoms, forming a distorted octahedral conformation. A molecule of N-phthaloylglycinate is connected by van der Waals contact and H-bonds. 相似文献
212.
M. Sh. Ramadan Amina M. Hafez H. Sadek A. El-Zyadi 《Journal of solution chemistry》1996,25(8):797-812
Conductance data for dilute solutions of S-n-butylisothiouronium bromide and iodide salts as well as S-alkylisothiouronium picrates (alkyl=methyl to octyl) are reported in pure nitrobenzene and methanol at 25, 35, and 45°C. The data were analyzed using Fuoss' equation (1980) (F-80) to obtain the three adjustable parameters; molar conductance at infinite dilution o, association constant KA and the association distance R that minimize the standard deviation . The variation of the parameters for each solvent are discussed with the variation of both cationic and anionic size as well as with temperature. It was found that the solvent-separated ion pair model (SSIP) can be applied in methanol for the salts under investigation. The thermodynamic parameters related to ion-pair formation were calculated and interpreted. The plots of #x039B;o vs. the reciprocal of the molecular weight M were used to separate the molar conductances into values for the individual ions. 相似文献
213.
Ashraf A. Aly Mohamed Ramadan Ahmed A. M. El‐Reedy 《Journal of heterocyclic chemistry》2019,56(2):642-645
Reaction of four equivalents of 4‐hydroxyquinolin‐2(1H)‐ones with one equivalent of acenaphthoquinone in absolute ethanol, containing catalytic triethylamine, gave 3,3′,3″,3?‐(1,2‐dihydroacenaphthylene)‐1,1,2,2‐tetrayl‐tetrakis(4‐hydroxyquinolin‐2(1H)‐ones) in a good to excellent yields. The structures of the products were elucidated by 1H NMR, 13C NMR, NMR, IR, mass spectra, and elemental analyses. 相似文献
214.
Ayman M. Atta Ahmed M. Ramadan K. A. Shaffei Amal M. Nassar N. S. Ahmed Mohamed Fekry 《Journal of Dispersion Science and Technology》2013,34(7):1100-1110
Ester-adduct derivatives of rosin were synthesized by reacting rosin with polyethylene glycol 600 (PEG 600) or 2000 (PEG2000) and maleic anhydride (MA) at elevated temperature. These derivatives were evaluated for acid number, FTIR spectroscopy, molecular weight (Mw), and polydispersity. The derivatives were soluble in organic solvents; aqueous solubility was pH dependent. Rosin-imides were synthesized from a rosin ester-maleic anhydride adducts. It was condensed with diaminobutane or triethylene tetramine to obtain rosinimides. This imide was etherified by reaction with PEG in the presence of β,β′-dichlorodiethyl ether as a linking agent and NaOH as a catalyst. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The surface tension, critical micelle concentration and surface activities were determined at different temperatures. Surface parameters such as surface excess concentration (Γmax), the area per molecule at interface (Amin), and the effectiveness of surface tension reduction (πCMC) were determined from the adsorption isotherms of the prepared surfactants. Some thermodynamic data for the adsorption process were calculated and are discussed. 相似文献
215.
Basim Azmy Silwanis Ramadan I. El-Sokkary Mina A. Nashed Hans Paulsen 《Journal of carbohydrate chemistry》2013,32(6):1067-1078
ABSTRACT A systematic study is presented for the most common methods used for the preparation of the disaccharide benzyl O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl)-(1→'4)-3,6-di-O-benzoyl-2-deoxy-2-phthalimido-β-D-glucopyranoside (9) from “standard 2-amino-2-deoxyglucopyranosyl donors” 1-6 and benzyl 3,6-di-O-benzoyl-2-deoxy-2-phthalimido-β-D-glucopyranoside (7) as an acceptor. It was found that the highest yield was obtained when the trichloroacetimidate derivative 1 was coupled to the 4 position of acceptor 7. In an analogous manner, the disaccharides allyl O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl)-(1→'4)-3,6,-di-O-benzoyl-2-deoxy-2-phthalimido-β-D-glucopyranoside (10), benzyl O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl)-(1→'4)-3,6-di-O-benzoyl-2-deoxy-2-phthalimido-β-D-galactopyranoside (12), and allyl O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl)-(1→'3)-4,6-O-benzylidene-2-deoxy-2-phthalimido-β-D-glucopyranoside (14) were prepared. 相似文献
216.
217.
Fawzya I. Elshami Abd El-Motaleb M. Ramadan Mohamed M. Ibrahim Ibrahim M. El-Mehasseb Salih Al-Juaid Shaban Y. Shaban 《应用有机金属化学》2020,34(3):e5437
In quest of antimicrobial and anticancer agents, metformin containing Ni (II) complexes, [Ni (Met)2]Cl·OH ( 1 ) and [Ni (Met)(IDA)] ( 2 ) {Met: metformin, IDA: iminodiacetic acid} were synthesized and X-ray structure of 1 is four-coordinate square planar geometry. Bovine serum albumin (BSA) interaction and binding studies to Met, IDA and their Ni (II) complexes were investigated and showed a strong interaction. A static quenching process was proposed at low concentrations of compounds whereas, combined quenching process was observed for 1 and 2 at higher concentrations. Kinetic stability, affinity and association constants of compounds-BSA were studied using stopped-flow technique and a mechanism was proposed: a fast and reversible step of BSA binding including complex formation and dissociation was proposed; for the second step, a reversible reaction was observed for 1 and 2 whereas, an irreversible reaction with Met and IDA was observed indicating that coordination with nickel ions change the interaction mechanism. Additionally, the antibacterial investigation against both Gram-positive and Gram-negative bacteria showed that all compounds exhibited significant activities. They also show cytotoxicity against HepG2 human liver cancer cell but the half maximal inhibitory concentration (IC50) values obtained for the cell lines were higher in comparison with cisplatin. Although Met-BSA and IDA-BSA are kinetically more stable than that of 1 -BSA and 2 -BSA, 1 -BSA and 2 -BSA showed better antibacterial and cytotoxic activities which is in agreement with the binding constants. 相似文献
218.
Aldbea Ftema W. Ibrahim N. B. Abdullah Mustaffa Hj. Shaiboub Ramadan E. 《Journal of Sol-Gel Science and Technology》2012,62(3):483-489
Terbium-doped yttrium iron garnet (TbxY3−x Fe5O12; x = 0.0, 0.2, 0.4, 0.6 and 0.8) nanoparticles thin films have been prepared onto quartz substrate by sol–gel method followed
by spin coating process. Annealing of the films was processed at 900 °C in air for 2 h. The structures were investigated by
using an X-ray diffractometer (XRD) and a field emission scanning electron microscope (FE-SEM). The magnetic properties were
studied by a vibrating sample magnetometer (VSM). The XRD patterns of the films were consistent with a single phase garnet
structure. The lattice parameter was initially increased with Tb3+ concentration due to the larger size of the Tb3+ ion compared to Y3+ ion, but a decrease in lattice parameter was observed at higher Tb3+ concentration due to the effect of film’s thickness. FE-SEM micrographs reveal that the particles were highly agglomerated.
The grain’s sizes for all films were in the range of 40–59 nm. The magnetic measurements at room temperature (25 °C) show
that the saturation magnetization (Ms) of the films was reduced with the increase in Tb3+ ions, which due to the antiparallel alignment between Tb3+ ions and Fe3+ ions. The films illustrate normal shapes of hysteresis loops except Tb0.2Y2.8Fe5O12 and Tb0.4Y2.6Fe5O12 films exhibiting two steps increments before being saturated. The coercivity values (Hc) demonstrate non linear dependency with the terbium concentration (x). 相似文献
219.
Qasem Ramadan Lay Christophe William Teo Li ShuJun Feng Han Hua 《Analytica chimica acta》2010,673(1):101-3640
Simultaneous sample washing and concentration of two waterborne pathogen samples were demonstrated using a rotational magnetic system under continuous flow conditions. The rotation of periodically arranged small permanent magnets close to a fluidic channel carrying magnetic particle suspension allows the trapping and release of particles along the fluidic channel in a periodic manner. Each trapping and release event resembles one washing cycle.The performance of the magnetic separation system (MSS) was evaluated in order to test its functionality to isolate magnetic-labelled protozoan cells from filtered, concentrated tap water, secondary effluent water, and purified water. Experimental protocols described in US Environmental Protection Agency method 1623 which rely on the use of a magnetic particle concentrator, were applied to test and compare our continuous flow cell separation system to the standard magnetic bead-based isolation instruments. The recovery efficiencies for Giardia cysts using the magnetic tube holder and our magnetic separation system were 90.5% and 90.1%, respectively, from a tap water matrix and about 31% and 18.5%, respectively, from a spiked secondary effluent matrix. The recovery efficiencies for Cryptosporidium cells using the magnetic tube holder and our magnetic separation system were 90% and 83.3%, respectively, from a tap water matrix and about 38% and 36%, respectively, from a spiked secondary effluent matrix. Recoveries from all matrices with the continuous flow system were typically higher in glass tubing conduits than in molded plastic conduits. 相似文献
220.