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Organic Complexes (organic + complex)
Selected AbstractsSynthesis and crystal structure of a new inorganic , organic complex: (4-ClC7H6NH3)9[Nd(P6O18)2]·9H2OCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2007O. Amri Abstract Single crystals of (4-ClC7H6NH3)9[Nd(P6O18)2]·9H2O were synthesized in aqueous solution. This compound crystallizes in a triclinic P1 unit-cell, with a = 14.898(6), b = 18.049(7), c = 20.695(6)Å, , = 102.04(3), , = 100.49(3), , = 98.82(3)°, V = 5245(4) Å3 and Z = 2. The crystal structure has been solved and refined to R = 0.043 (Rw = 0.061) for 20420 observed reflections. The atomic arrangement of the title compound can be described as infinite layers built by complex of Neodyme [Nd(P6O18)2] and nine water molecules. The organic cations are located in the space delimited by the successive inorganic layers. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation and Fluorescent and Magnetic Properties of Polyurethane/Eu(MA)3 FilmsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 24 2007Shuxue Zhou Abstract Europium(III) (Eu3+)-doped polyurethane films were prepared by mixing Eu-methacrylic acid complex (Eu(MA)3) with aliphatic polyurethane oligomer and subsequently curing under UV irradiation. Transmission electron microscopy photos and the appearance of the resulting hybrid films showed that phase separation occurred only at an Eu(MA)3 content above 20 wt.-%. Fluorescence spectra indicated that the fluorescence of Eu3+ was barely influenced by the polyurethane matrix and its intensity increased with an Eu(MA)3 content in the range of approximately 0 to 10 wt.-%. An obvious applied external-field-dependent magnetization (M) of polyurethane/Eu(MA)3 films, namely, an increasing M at low field and a decreasing M at high field, was observed at room temperature from the hysteresis loops, which was influenced by both the Eu(MA)3 content and the ultrasonication imposed on the coatings before curing. It seems that ultrasonication leads to a thermodynamically-unstable structure of Eu3+ in hybrid films, which can be fixed by UV curing but gradually rearranges to its original form during the thermal-curing process, and enhances the diamagnetic part of the hybrid film. Thus, the magnetic property of Eu3+ -doped polyurethane film at room temperature can be adjusted by simply changing the preparation method and the Eu(MA)3 content instead of the type of Eu3+ -organic complex. [source] Molecular characterization and corrosion behavior of thermophilic (55,°C) SRB Desulfotomaculum kuznetsovii isolated from cooling tower in petroleum refineryMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 9 2009B. Anandkumar Abstract Desulfotomaculum kuznetsovii (D. kuznetsovii), a thermophilic sulfate-reducing bacterium (SRB), was identified in a cooling tower of a petroleum refinery by 16S rRNA gene sequencing and its functional gene encoding dissimilatory sulfite reductase (dsrAB). The thermophilic sulfate-reducing bacterial species have been reported for the first time in the cooling towers of an Indian petroleum refinery. The protein coded by dsrAB gene was cloned, expressed, and identified using recombinant DNA technology. Weight loss method, electrochemical and surface analysis showed the corrosion behavior of the isolate. In the presence of D. kuznetsovii, the corrosion rate was higher when compared to control at 55,°C. It suppresses the anodic reaction and enhances the cathodic reaction by the production of organic complex and iron sulfide, respectively. Numerous pitting were noticed on mild steel which is due to the presence of D. kuznetsovii and its role in the corrosion process has been discussed. [source] Formation of copper complexes in landfill leachate and their toxicity to zebrafish embryosENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2000Jonathon K. Fraser Abstract Toxic metal organic complexeshavenot been found in natural waters, although someorganicacids form bioavailable lipophilic and metabolite-type metal complexes. Landfill leachates usually contain organic acids and in the urban environment these leachates, when mixed with storm waters containing Cu, could be a source of toxic Cu organic complexes in streams and estuaries. We investigated the formation of Cu complexes in the leachate from an active urban landfill and found that some of the complexes formed were toxic to zebrafish embryos. High and low nominal molecular weight (NMWT) fractions; >5,000 Da and <700 Da, of leachate both formed Cu complexes with almost identical Cu complexing characteristics but the toxicity was due solely to the low NMWT complexes formed in the <700 Da fraction. Chemical equilibrium modelling with MINTEQA2 and H and Cu complex conditional association constants and ligand concentrations obtained from pH and Cu titrations with a Cu ion-selective electrode and van den Berg,Ruzic analyses of the titration data was used to calculate the copper speciation in the embryo test solutions. This calculated speciation, which was confirmed by measurements of Cu2+ in the test solutions, enabled the toxicity due to the free Cu ion and to the Cu complexes to be distinguished. [source] Theoretical investigation of electron transfer transition in tetracyanoethylene-contained organic complexesJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 9 2002Xiang-Yuan Li Abstract In this work, the authors use complete active space self-consistent field method to investigate the photoinduced charge-separated states and the electron transfer transition in complexes ethylene-tetracyanoethylene and tetramethylethylene-tetracyanoethylene. Geometries of isolated tetracyanoethylene, ethylene, and tetramethylethylene have been optimized. The ground state and the low-lying excited states of ethylene and tetracyanoethylene have been optimized. The state energies in the gas phase have been obtained and compared with the experimentally observed values. The torsion barrier of tetracyanoethylene has been investigated through the state energy calculation at different conformations. Attention has been particularly paid to the charge-separated states and the electron transfer transition of complexes. The stacked conformations of the donor,acceptor complexes have been chosen for the optimization of the ground and low-lying excited states. Equilibrium solvation has been considered by means of conductor-like screening model both in water and in dichloromethane. It has been found that the donor and tetracyanoethylene remain neutral in complexes in ground state 1A1 and in lowest triplet state 3B1, but charge separation appears in excited singlet state 1B1. Through the correction of nonequilibrium solvation energy based on the spherical cavity approximation, ,,,* electron transfer transition energies have been obtained. Compared with the experimental measurements in dichloromethane, the theoretical results in the same solvent are found higher by about 0.5 eV. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 874,886, 2002 [source] Encapsulating Eu3+ complex doped layers to improve Si-based solar cell efficiencyPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 8 2009Alessia Le Donne Abstract This paper reports the electrical characterization of commercially available crystalline silicon solar cells encapsulated with poly-vinylacetate doped with different Eu3+ organic complexes. The inclusion of these complexes in the encapsulating matrix allows down-shifting of the solar spectrum components below 420,nm toward the maximum quantum efficiency of the solar cells. This effect has been proven under Air Mass 1·5 conditions (simulating terrestrial applications) where an increase of the total power delivered by the encapsulated cells has been observed. Moreover, this enhancement has been obtained using very low percentage by weight of organolanthanide dopants, allowing a reduction in the Watt peak price. At higher concentrations a strong quenching of the energy transfer from the organic antenna to the lanthanide ion has been observed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effect of yeast extract on speciation and bioavailability of nickel and cobalt in anaerobic bioreactorsBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2003G. Gonzalez-Gil Abstract The speciation of metals plays an important role in their bioavailability. In the case of anaerobic reactors for the treatment of wastewaters, the ubiquitous presence of sulfide leads to extensive precipitation of metals like nickel and cobalt, which are essential for the metabolism of the anaerobic microorganisms that carry out the mineralization of the pollutants present in the wastewater. In practice, nickel, cobalt, and iron are added in excessive amounts to full-scale installations. This study is concerned with the complexation of nickel and cobalt with yeast extract and its effect on the biogas production by methanogenic biomass. Adsorptive stripping voltammetry (AdSV) was used to get information about the stability and complexing capacity of the metal,yeast extract complexes formed. Nickel and cobalt form relatively strong organic complexes with yeast extract. The bioavailability of these essential metals in anaerobic batch reactors was dramatically increased by the addition of yeast extract. This is due to the formation of dissolved bioavailable complexes, which favors the dissolution of metals from their sulfides. Trace doses of yeast extract may be effective in keeping additions of essential metals to anaerobic reactors at a minimum. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 134,142, 2003. [source] Steering Two-Dimensional Molecular Growth via Dipolar InteractionCHEMPHYSCHEM, Issue 12 2009Stefan Kuck Molecular networks: Chiral and metallized Salen molecules on a Cu(111) are investigated using local probe techniques (see figure). Whereas for the parent Co-Salen molecule no self-assembly is observed, in the metal,organic complexes the growth of large and regular molecular networks is achieved through a target-oriented synthetic design of the local electrostatic dipolar molecular fields. [source] Prediction of Decomposition Temperature for Lanthanide Complexes Involving Cyclopentadienyl and Benzohydroxamic Acid Ligand by ANNsCHINESE JOURNAL OF CHEMISTRY, Issue 10 2002Yi-Min Sun Abstract The decomposition temperatures of the lanthanide organic complexes (,5 -C5H5)2 Ln(C6H5CONHO) involving cyclopentadienyl and benzohydroxamic acid ligands were calculated and predicted by the model based on ANNs (artificial neural networks) method. The comparison was carried out between results from ANNs method and traditional regression method. It is proved that ANNs could be used more efficiently for the prediction of decomposition temperature of lanthanide organic complexes. [source] | ||||||||||||||||