Search results for "Complexes."
showing 10 items of 857 documents
Analyser les catastrophes : une approche par les comportements humains
2011
La catastrophe est une forme de crise qui altère profondément un système social soumis à une situation de stress collectif. Ce dernier est confronté à une agression qui surpasse ses capacités d'adaptation induisant une désorganisation sociale et territoriale plus ou moins longue. L'environnement physique, qui influe peu sur les comportements observés en situation normale, contrairement à l'environnement social, impose de nouvelles façons d'agir, de nouveaux modes d'organisation, quelles que soient les échelles considérées. Il s'agit au moment du choc d'assurer sa survie et celle de ses proches (à condition qu'ils ne soient pas trop éloignés spatialement), puis une fois le danger écarté, de …
Coordination chemistry on surfaces through vapor phase processing: smart molecular/graphene heterostructures based on spin-crossover complexes and 2D…
2023
Los compuestos de coordinación están últimamente focalizando la atención de los investigadores en el campo de la nanociencia. Particular interés están generando aquellos compuestos con propiedades magnéticas de cara a su integración a la nanoescala en ramas como la electrónica y/o la espintrónica moleculares. Sin embargo, para su uso real en dispositivos destinados a estas aplicaciones, su procesabilidad es un requisito indispensable. En el marco de esta necesidad, la presente tesis doctoral se ha destinado al estudio del procesado sobre superficies mediante técnicas de fase gas de dos tipos distintos de compuestos de coordinación. Por tanto, el trabajo se ha dividido en dos partes. La prim…
A nucleophilic gold complex.
2019
Solid-state auride salts featuring the negatively charged Au– ion are known to be stable in the presence of alkali metal counterions. While such electron-rich species might be expected to be nucleophilic (in the same manner as I–, for example), their instability in solution means that this has not been verified experimentally. Here we report a two-coordinate gold complex (NON)AlAuPtBu3 (where NON is the chelating tridentate ligand 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene) that features a strongly polarized bond, Auδ––Alδ+. This is synthesized by reaction of the potassium aluminyl compound [K{Al(NON)}]2 with tBu3PAuI. Computational studies of the complex, includ…
Anticancer study of heterobimetallic platinum(II)-ruthenium(II) and platinum(II)-rhodium(III) complexes with bridging dithiooxamide ligand
2019
Abstract Three heterobimetallic platinum (II)/ruthenium (II) and platinum (II)/rhodium (III) complexes, A: Pt{S–S2C2(NR)2H}{μ-S2C2(NR)2}-[Ru (p-cymene)Cl], R = isoamyl; B: Pt{S–S2C2(NR)2H}{μ-S2C2(NR)2}[Rh (phpy)2], R = isoamyl; C: [Pt{S–S2C2(NR)2H}{μ-S2C2(NR)2}-[Rh(C5Me5)Cl]], R = benzyl, were prepared from mononuclear complexes 1 and 2, 1: [Pt (H-isoamyl2DTO)2]; 2: [Pt (H-benzyl2DTO)2], DTO = dithiooxamide, by reaction of 1 or 2 with the corresponding chlorido-bridged dimers, [Rh(C5Me5)Cl (μ-Cl)]2, [Ru (p-cymene)Cl (μ-Cl)]2 or [Rh (phpy)2 (μ-Cl)]2, and then evaluated as anticancer agents for the inhibition of the three proteolytic activities of human 20S proteasome, one of the main target …
Influence of structural elements on iron(III) chelating properties in a new series of amino acid-derived monohydroxamates
2018
Abstract A series of amino acid-derived monohydroxamate compounds A1 – A7 was synthesized and characterized for their coordination properties of Fe(III). The series varies in their skeletal lengths and compositions; some compounds lack external substituents, others are substituted with external functional amino or carboxylic groups, or alternatively inert methyl. Undertaken investigations allowed the determination of stoichiometry, stability constants and spectroscopic parameters of formed ferric complexes. Incorporation of an external functional group with a dissociable proton affects the coordination behavior; the presence of carboxylic or amino groups hampers the formation of mono-, di- …
Enantiodivergent synthesis of P-chirogenic phosphines
2010
International audience; Several approaches for the enantiodivergent synthesis of P-chirogenic mono- and diphosphines are described, using ephedrine methodology and phosphine borane chemistry. Firstly, both enantiomers of a tertiary phosphine can be obtained starting from the same oxazaphospholidine borane complex, prepared from (+)-ephedrine, when changing the order of addition of the organolithium reagents during the synthetic pathway. The second approach is based on the chlorophosphine boranes, which react with an organolithium reagent, to afford the corresponding phosphines with inversion of configuration. In the case where the chlorophosphine borane reacts with the t-butyl lithium reage…
Ion pair complexes and anion binding in the solution of a ditopic receptor.
2016
The synthesis and crystal structures with alkali halides of a ditopic benzo-15-crown-5 bis-urea receptor have been presented. In addition, the anion binding properties of and its alkali metal complexes in solution are presented. A comprehensive single-crystal X-ray crystallographic study of , all together 13 crystal structures, including the ion pair complexes with NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbF, RbCl, and RbI, give a detailed view of how behaves in the solid-state with different alkali halides depending on the size of the cation and anion. In the solid-state forms a 1 : 1 complex with a sodium cation and the anion is complexed as a contact (NaCl) or a separate ion pair (NaBr, NaI).…
Pseudopeptidic ligands: exploring the self-assembly of isophthaloylbisglycine (H2IBG) and divalent metal ions.
2012
We present a systematic study of the complexation of the new pseudopeptidic ligand isophthaloylbisglycine (H(2)IBG) with divalent metal ions of varying ionic radius. This work represents the initial employment of H(2)IBG in the coordination chemistry of alkaline earth, 3d transition, Zn(II) and Cd(II) metal elements. Infrared, NMR, thermal, magnetic, adsorption and theoretical studies of these compounds are also discussed.
N-Glycosylamines of 4,6-O-ethylidene-alpha-D-glucopyranose: synthesis, characterisation and structure of CO2H, Cl and F ortho-substituted phenyl deri…
2000
A saccharide based ligand suitable for metal binding (HLCOOH) has been synthesized using 4,6-O-ethylidene-alpha-D-glucopyranose (4,6-O-EGP) and anthranilic acid. A few analogous glycosylamines with chloro and fluoro ortho substitutions have also been synthesized and characterised. Complexes of HLCOOH with Na+, K+, Mg2+, Ca2+, Ba2+, Cd2+ and Hg2+ have been isolated and characterised fully. The crystal structures of 4,6-O-EGP, the chloro analogue of HLCOOH and the K+ complex of L-COOH are established. The anomeric nature, orientation of the binding core and the co-ordination aspects of K+ have been derived from these structures.
Hydrolysis of (CH3)Hg+ in Different Ionic Media: Salt Effects and Complex Formation
1998
The hydrolysis of monomethylmercury(II) was studied potentiometrically, in NaNO3, Na2SO4, and NaCl aqueous solution, in a wide range of ionic strengths (NaNO3, 0 ≤ I ≤ 3.25; Na2SO4, 0 ≤ I ≤ 1; NaCl, 0 ≤ I ≤ 3 mol dm-3) and at t = 25 °C. For the reaction (CH3)Hg+ = (CH3)Hg(OH)° + H+, we found log K1 = −4.528 (I = 0 mol dm-3). The species [(CH3)Hg]2(OH)+ was also found, with log β2 = −2.15. Monomethylmercury(II) forms quite strong complexes with Cl- (log K = 5.45, I = 0 mol dm-3) and SO42- (log K = 2.64, I = 0 mol dm-3). The dependence on ionic strength of formation constants was considered by using a Debye−Huckel type equation. Hydrolysis and complex formation constants (at different ionic s…