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M.A. Zaitoun T. Kim K. Momani A.K. El-Qisairi N.E. Radwan 《Journal of luminescence》2008,128(2):227-231
The Lanthanide complexes Eu-2.2.1 and Eu-2.2.2 were synthesized and then incorporated into silica based transparent organic-inorganic hybrid material by the sol-gel method as an example of how doped xerogel materials are emerging as an important means of producing new materials. The produced gels were diagnosed to monitor emission spectra of the luminescent trivalent europium (Eu3+) complexes; emissions were compared to those for gels containing uncomplexed Eu3+. Results of the experiments (emission and lifetimes) concerning the coordination sphere composition showed that a cryptand ligand with aromatic groups (short range effect) and the hydrophobic gel host (long range effect) settle efficient action in the antenna effect and isolate the central ion from efficient quenchers, as e.g. water molecules. Each ligand imposed a distinct splitting pattern on the europium emission bands that helps identify them. 相似文献
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Mukarram H. Zaghal Hanan A. Qaseer Arab K. El-Qisairi Solhe F. Alshahateet Mazin Y. Shatnawi Louise N. Dawe 《Journal of chemical crystallography》2009,39(8):564-567
Abstract The X-ray structure of 6,7-dihydro-1,4-di(2′-pyridyl)-5H-cyclopenta[d]pyridazine ligand (5-dppn) shows the existence of a trans/trans conformation. The 5-dppn crystallizes in a triclinic space group P-1 with a = 7.1048(15) ?; b = 9.008(2) ?; c = 10.986(3) ?; α = 88.279(16)°; β = 85.454(15)°; γ = 69.104(12)°; V = 654.7(3) ?3 and Z = 2. The analysis of 5-dppn crystal structure demonstrates the presence of edge-edge Ar–H···N and face-face Aliph-H···N centrosymmetric
dimer interactions. The unit cell packing arrangement confirmed the presence of two molecules opposite to each other.
Index Abstract The X-ray structure of 6,7-dihydro-1,4-di(2′-pyridyl)-5H-cyclopenta[d]pyridazine ligand (5-dppn) shows the existence of a trans/trans conformation.
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Othman A. Hamed Arab El-Qisairi Hanan Qaseer Emad M. Hamed Patrick M. Henry Daniel P. Becker 《Tetrahedron letters》2012,53(22):2699-2701
The oxidation of ketones by a chiral bimetallic palladium(II) complex in the presence of CuCl2 in THF–water solvents gave an enantioselective synthesis of α-hydroxyketones in catalytic oxidation utilizing an atmosphere of oxygen. The ee’s ranged from 61% to 92%. The reaction was accelerated by addition of strong acid that presumably increases the rate of enolization. 相似文献
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El-Qisairi AK Qaseer HA Katsigras G Lorenzi P Trivedi U Tracz S Hartman A Miller JA Henry PM 《Organic letters》2003,5(4):439-441
[reaction: see text] The oxidation of olefins by chiral monometallic and bimetallic Pd(II)-Cu(II) catalysts in bromide-containing aqueous-THF reaction mixtures produced chiral 1,2-dibromides. With alpha-olefins, the ee's were about 95% while most of the internal alkenes gave somewhat lower enantioselectivities ( approximately 80%). 相似文献
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Zaghal Mukarram H. Abu-Obeid Mona A. Atfah Mohammad A. El-Qisairi Arab K. Qaseer Hanan A. Ali Basem F. 《Transition Metal Chemistry》2001,26(4-5):517-522
3,6-Bis(2-pyridyl)pyridazine derivatives (n-dppn) react with hydrated rhodium(III) chloride and bromide (prepared in situ) to give cis-[Rh(n-dppn)2Cl2]PF6·xH2O (n = 5, 6, 7, 8) and cis-[Rh(n-dppn)2Br2]Br·xH2O (n = 5, 7) complexes, which have been characterized by elemental analyses, conductivity measurements, i.r., electronic and 1H- and 13C-n.m.r. spectra. 相似文献
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