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Metal Ratio (metal + ratio)
Selected AbstractsXAS, ESR and Potentiometric Studies of Three Dinuclear N,N, -para -Xylylenebis(tetraazamacrocycle)copper(II) Complexes , X-ray Crystal Structure of [N,N,- p -Xylylenebis(cyclen)]copper(II)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2003Mathieu Soibinet Abstract Dicopper complexes with N,N, - p -xylylenebis(cyclam or cyclen) and with the heteroditopic N,N, - p -xylylenebis(cyclam-cyclen) were synthesized. An X-ray study of the N,N, - p -xylylenebis(cyclen)dicopper complex showed that the copper(II) ion is five-coordinate with an H2O molecule in apical position. With this ligand, a polymeric chain was also obtained in the presence of KSCN. The terminal donor atoms of the bridging NCS, anion are coordinated in apical position to the square-pyramidal copper(II) ion. Two alternating kinds of Cu2L4+ moieties are present in the chain, the first with two N4S chromophores and the second with two N5 chromophores. EXAFS and XANES results are in agreement with a five-coordinate copper ion in the cyclen unit and a six-coordinate copper ion in the cyclam unit. Thermodynamic constants were determined by potentiometry. The existence of dinuclear Cu2L4+ species (ligand/metal ratio < 1) and mononuclear CuLHn(2+n)+ species (ligand/metal ratio > 1) were confirmed by an ESR study at variable pH. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Epitaxial Sn1-xPbxS nanorods on iso-compositional thin filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2010K. Bente Abstract Based on SnS (Herzenbergite) , SnPbS2 (Teallite) mixed crystals with orthorhombic layer structures, thin films and lawns of Sn1-xPbxS nanorods were produced using hot wall vacuum deposition method (HWVD). The lawn was formed onto the surface of an underlying thin Sn1-xPbxS film which is build by differently oriented blocks. The density of rods arranged like a lawn depends on the metal ratio and substrate temperature. X-ray and TEM analysis of the epitaxial material showed preferential (001) orientation perpendicular to the surface of the glass substrate. The roughness of the films measured by atomic force microscopy was in the range of Rq = 49.5,86.3 nm depending on lead concentration The rods were about 500 nm high and 300 nm in diameter. As revealed by TEM-EDX experiments the droplet at the tip of rods consists of tin. Therefore it is assumed the rods grew via a self-consuming vapor,liquid,solid (VLS) mechanism. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] One-Dimensional CdII Coordination Polymers: Solid Solutions with NiII, Thermal Stabilities and StructuresEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2004Dejana Vujovic Abstract Reactions of Cd(NCS)2 with 2-, 3- and 4-aminobenzonitrile ligands (2ABN, 3ABN and 4ABN respectively) have produced one-dimensional chain polymers of the general formula [M(NCS)2(ABN)2]n with the metal centres linked by double NCS, bridges. The three cadmium polymers [Cd(NCS)2(3ABN)2]n (1), [Cd(NCS)2(2ABN)2]n (2) and [Cd(NCS)2(4ABN)2]n (3) all differ in their hydrogen-bonding patterns. In terms of ABN coordination, both 1 and 2 exhibit terminal amine coordination while in 3 the ABNs are coordinated through the cyano groups. Crystalline solid solutions of 1 of general formula [Cd1,xNix(NCS)2(3ABN)2]n, containing nickel and cadmium in varying proportions, have also been prepared in order to establish the influence of the metal ratio on the thermal stability and bonding parameters of the polymers. The coordination polymers are not good candidates for forming clathrates while their thermal stability (ranging between 147 and 244 °C) depends on the position of functional groups on the ABN ligands and on the Cd:Ni ratio in the solid solutions. The new polymers have been characterised by single crystal X-ray diffraction, X-ray powder diffraction, electron microscopy, infrared spectroscopy, thermogravimetry and differential scanning calorimetry. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Calculation of the electronic structure of AmO2 and Pr6O11 for XANES analysis with redox propertyINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 12 2009Chikashi Suzuki Abstract We calculated X-ray absorption near-edge structure (XANES) of Am LIII of AmO2 and Pr LIII of Pr6O11 using the relativistic discrete-variational (DV)-X, method based on the Dirac,Slater method, and compared it with the experimental spectra. These spectra were calculated on a model of AmO2 ([AmO8]12,) and Pr6O11 ([PrO8]12,). In spite of using small cluster models, the calculated spectra were in good agreement with the experiment ones. Besides, we calculated the electronic structure of AmO2 and Pr6O11 to analyze the peak structures of XANES. From this calculation, it was found that O s, p, and f components had influence on the specific peak structures but that O d component had influence on various peak structures for AmO2 and Pr6O11. From this result, it was suggested that the change of the electronic structure of actinide 6d and O d or f was important for actinide LIII XANES corresponding to oxygen to metal ratio in the oxide nuclear fuel. On the basis of these results, we calculated the fine structures of densities of states and the transition energy from the HOMO to the white line of AmO2, UO2, and Pr6O11 and investigated redox properties of Am and U in the oxide nuclear fuel with the evaluation of validity of Pr as simulant materials of Am. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] | ||||||||||