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AbstractAbstract
[en] Quantum chemical and molecular dynamics simulations have been performed on the coordination of lanthanide(III) cations (La(III), Eu(III), Lu(III)) by nitrate ions NO3-, diamides TEEEMA (tetra-ethyl-ethyl-ethoxy-malonamide) and TMDGA (tetra-methyl-diglycolamide), and by Btp ligands (bis-triazinyl-pyridine) in the gas phase and in water or methanol solution. In the gas phase, the NO3- anions may present monodentate or bidentate coordination to the cation in presence of water molecules. In water, nitrates remain monodentate, whereas they usually are bidentate in the solid state. For the [Ln(TEEEMA)2]3+ and [Ln(TMDGA2]3+ complexes, except in water solution (where the complexes dissociate), the ligands coordinate the cation by the amidic oxygens, with or without NO3- counter-ions. The coordination by ethoxy oxygen atoms, whose position differs between TEEEMA and TMDGA, is influenced by the presence of nitrates in the gas phase. In methanol, the ethoxy oxygen of TEEEMA does not coordinate the cations but the one of TMDGA does directly, or via a MeOH molecule. The cation-ligand interaction has been characterized for [Ln(Btp)1]3+ complexes in the gas phase, and for 1:1 to 1:3 complexes in solvent phase. In water, all complexes dissociate. In dry methanol, with or without chlorides, 1:1 complexes also dissociate, but in methanol with some water molecules and with chlorides, the ligand remains in the second sphere of the cation. 1:3 complexes for Eu(III) and Lu(III) remain associated in methanol, whereas the La(III) complex dissociates. As far as the QC and MD models are relatively simple, the results give information on the complexation behaviour of ligands with these lanthanide(III) cations. (author)
[fr]
Des etudes theoriques par chimie quantique (CQ) et dynamique moleculaire (DM) ont porte sur l'etude de la coordination dans le vide et en phase solvant de cations lanthanide(III) (La(III), Eu(III), Lu(III)) par des ions nitrate NO3-, des diamides TEEEMA (tetra-ethyl-ethyl-ethoxymalonamide) et TMDGA (tetra-methyl-diglycolamide), et des ligands azotes Btp (bistriazinyl- pyridine). Dans le vide, les NO3- peuvent etre aussi bien monodentes que bidentes au cation en presence de molecules d'eau et ils restent monodentes dans l'eau, alors qu'ils sont generalement bidentes a l'etat solide. A part dans l'eau ou ils se dissocient, la coordination des complexes [Ln(TEEEMA)2]3+ et [Ln(TMDGA)2]3+ se fait principalement par les oxygenes amidiques, avec ou sans contre-ions NO3-. La coordination du cation par l'oxygene ethoxy, dont la position differe entre le TEEEMA et le TMDGA, est influencee par la presence des nitrates dans le vide. Dans le methanol, l'oxygene ethoxy du TEEEMA ne vient pas coordiner le cation alors que celui du TMDGA peut s'y lier soit directement, soit via une molecule de solvant. L'interaction cation-ligand a ete caracterisee pour les complexes [Ln(Btp)1]3+ dans le vide, et pour les complexes 1:1 a 1:3 en phase solvant. Dans l'eau, tous les complexes se dissocient. Dans le methanol sec, avec ou sans chlorures, les complexes 1:1 se dissocient aussi, mais dans le methanol humide et en presence de chlorures, le ligand reste en deuxieme sphere du cation. Les complexes 1:3 de Eu(III) et Lu(III) restent associes dans le methanol, et celui de La(III) se dissocie. Bien que les modeles utilises en CQ et en DM soient relativement simples, les resultats obtenus ont apporte des informations sur les comportements relatifs des ligands sur la complexation de ces cations lanthanide(III)Original Title
Etude theorique de la coordination de cations lanthanide trivalents par des ions nitrate, des diamides et des ligands azotes
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15 Dec 2001; 212 p; 243 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS website for current contact and E-mail addresses: http://www.iaea.org/inis/Contacts/; Also available from Service Commun de la Documentation, 2, rue Blaise Pascal, CS 41037/F - 67070 Strasbourg Cedex, (France); Chimie Informatique et Theorique
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ACTINIDE COMPLEXES, ACTINIDES, AMIDES, BOND LENGTHS, COMPUTERIZED SIMULATION, COORDINATION NUMBER, DIAMEX PROCESS, HARTREE-FOCK METHOD, METHANOL, MOLECULAR DYNAMICS METHOD, NITRATES, PHYSICAL PROPERTIES, RADIOACTIVE WASTES, RARE EARTH COMPLEXES, RARE EARTHS, SCHROEDINGER EQUATION, SOLVENT EXTRACTION
ALCOHOLS, APPROXIMATIONS, CALCULATION METHODS, COMPLEXES, DIFFERENTIAL EQUATIONS, DIMENSIONS, ELEMENTS, EQUATIONS, EXTRACTION, HYDROXY COMPOUNDS, LENGTH, MATERIALS, METALS, NITROGEN COMPOUNDS, ORGANIC COMPOUNDS, ORGANIC NITROGEN COMPOUNDS, OXYGEN COMPOUNDS, PARTIAL DIFFERENTIAL EQUATIONS, RADIOACTIVE MATERIALS, REPROCESSING, SEPARATION PROCESSES, SIMULATION, WASTES, WAVE EQUATIONS
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