Search results for "complexe"
showing 10 items of 920 documents
DFT computational study on Fe(III)-N,N′-ethylene-bis(salicylideneiminato) derivatives
2005
DFT calculations, at unrestricted B3LYP level, have been performed on the structures of three iron(III) complexes, Fe(Salen)Cl, [Fe(Salen)]+ and [Fe(Salen)OH2]+, where Salen is the anion of Schiff base ligand N,N′-ethylene-bis (salicylideneimine), considering the spin multiplicity (S) values 2, 4 and 6. The results obtained have been compared with the available structural an magnetic experimental data, allowing us to conclude that a stable form of the FeIII(Salen) complex in aqueous solution should be characterized by an energy stabilization of the S=4 compared to the S=6 state.
Uranium(VI) sequestration by polyacrylic and fulvic acids in aqueous solution
2011
Stability data on the formation of dioxouranium(VI) species with polyacrylic (PAA) and fulvic acids (FA) are reported with the aim to define quantitatively the sequestering capacity of these high molecular weight synthetic and naturally occurring ligands toward uranium(VI), in aqueous solution. Investigations were carried out at t = 25 °C in NaCl medium at different ionic strengths and in absence of supporting electrolyte for uranyl–fulvate (\( {{\text{UO}}_{2}}^{2+} \)–FA) and uranyl–polyacrylate (\( {{\text{UO}}_{ 2}}^{ 2+ } \)–PAA, PAA MW 2 kDa) systems, respectively. The experimental data are consistent with the following speciation models for the two systems investigated: (i) UO2(FA1),…
Ti(iv)-amino triphenolate complexes as effective catalysts for sulfoxidation
2010
C 3 -symmetric Ti (IV) amino triphenolate complexes efficiently catalyze, without previous activation and in excellent yields, the oxidation of sulfides at room temperature, using both CHP and the more environment friendly aqueous hydrogen peroxide as terminal oxidants, with catalyst loadings down to 0.01%. The Ti(IV) catalysts and the intermediate Ti(IV)-peroxo complexes have been characterized in solution by 1H NMR and ESI-MS techniques and via density functional studies.
Experimental virus evolution reveals a role of plant microtubule dynamics and TORTIFOLIA1/SPIRAL2 in RNA trafficking.
2014
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Kinetics of Zn2+ complexation by a ditopic phenanthroline-azamacrocyclic scorpiand-like receptor.
2012
Coordination of Zn(2+) to a ditopic phenanthroline-macrocycle receptor takes place in three steps, the first one being the coordination to the phenanthroline, followed by the slow movement of the metal to the polyamine macrocycle and a final re-arrangement to coordinate the pendent arm.
Stepwise formation of a pentanuclear Ni4Cu heterometallic complex exhibiting a vertex-sharing defective double-cubane core and diphenoxo- and phenoxo…
2013
Sequential reaction of a N5O3 octadentate tripodal ligand with Ni(2+) and subsequently with Cu(2+) and azide ligand afforded the first example of a heterobridged (phenoxo/μ(1,1)-azido) pentanuclear heterometallic (Ni4Cu) compound, which exhibits a centrosymmetric vertex-sharing defective double-cubane structure. The study of the magnetic properties reveals that the compound shows ferromagnetic interaction interactions, leading to an S = 9/2 spin ground state. Density functional theory calculations on the X-ray structure and model compounds predict ferromagnetic interactions through the magnetic exchange pathways involving each couple of metal ions.
2,2-Difluoro-3-(4-fluorophenyl)-2H-benzo[e][1,3,2]oxazaborinin-3-ium-2-uide
2017
There is one independent molecule in the asymmetric unit of the title compound, C13H9BF3NO, which crystallizes in the non-centrosymmetric space groupCc. In the molecular structure, the BF2-carrying ring is distorted from planarity and its mean plane makes a dihedral angle of 42.3 (1)° with the 4-fluorophenyl ring. F atoms are involved in all of the short intermolecular contacts of the crystal structure, which link molecules to form chains along [001] and [010].
Simultaneous stimulation of GABA and beta adrenergic receptors stabilizes isotypes of activated adenylyl cyclase heterocomplex
2004
Abstract Background We investigated how the synthesis of cAMP, stimulated by isoproterenol acting through β-adrenoreceptors and Gs, is strongly amplified by simultaneous incubation with baclofen. Baclofen is an agonist of δ-aminobutyric acid type B receptors [GABAB], known to inhibit adenylyl cyclase via Gi. Because these agents have opposite effects on cAMP levels, the unexpected increase in cAMP synthesis when they are applied simultaneously has been intensively investigated. From previous reports, it appears that cyclase type II contributes most significantly to this phenomenon. Results We found that simultaneous application of isoproterenol and baclofen specifically influences the assoc…
X-Ray crystallographic and computational study on uranyl-salophen complexes bearing nitro groups.
2017
In the solid state, salophen–UO2 complexes bearing one, two, or three NO2 groups lack the pronounced ligand curvature that represents a structural hallmark for this class of compounds. A detailed structural study based on single-crystal X-ray crystallography and computational methods, comprising molecular dynamics, gas-phase Hartree Fock, and DFT calculations, was carried out to investigate the coordination properties of the uranyl cation.
Reactivity of anticancer metallodrugs with serum proteins: New insights from size exclusion chromatography-ICP-MS and ESI-MS
2010
International audience; A method based on the coupling of high resolution size-exclusion liquid chromatography using a polymer stationary phase with inductively coupled plasma mass spectrometry was developed to study the interactions of two metallodrugs - cisplatin and RAPTA-T - with the serum proteins albumin and transferrin. In contrast to previous approaches, the technique allowed the total recovery of the metals from the column and was able to discriminate between the different species of the metallodrugs and their complexes with the proteins at femtomolar detection levels. Metal binding was found to be dependent on the protein concentration and on the incubation time of the sample. Cis…