Search results for "Chela"

Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites in the Axis

2010

A new example of a linear [5]rotaxane has been synthesized by using the traditional "gathering-and-threading" approach but based on an unusual axle incorporating a symmetrical bis(bidentate) chelating fragment built on a 4,7-phenanthroline core. The stoppering reaction is particularly noteworthy since, instead of using a trivial bulky stopper as precursor to the blocking group, two semistoppered copper-complexed [2]pseudorotaxanes (namely [2]semirotaxanes) are used, which leads to the desired [5]rotaxane in good yield. The efficiency of the method relies on the use of "click" chemistry, with its very mild conditions, and on the protection by a transition-metal (copper(I)) of the various coo…

Synthesis of bis(diphenylphosphinocyclopentadienyl) yttrium chloride complexes and heterodimetallic derivatives. X-ray structure of bis[(μ-chloro)bis…

1996

Abstract Reaction of lithium diphenylphosphinocyclopentadienide with YCl 3 or YCl 3 (THF) 3 and working lead to the formation of three yttrocene phosphines: the lithium metal adduct isolated as (Ph 2 PC 5 H 4 ) 2 Y(μ-Cl) 2 Li(THF) 2 · 0.5 LiCl ( 1 ), the chloride-bridged dimeric species {(Ph 2 PC 5 H 4 ) 2 Y(μ-Cl)} 2 ( 2 ), and the coordinated monometal species [(Ph 2 PC 5 H 4 ) 2 YCl(THF)] ( 3 ). The X-ray structure of 2 is remarkable in that the crystal exhibits two independent chloride-bridged dimers that differ in the arrangement ( syn, anti ) of the diphenylphosphino groups. Chelation of phosphorus atoms to a molydenum carbonyl moiety is also reported.

Imidotungsten(VI) complexes with chelating amino and imino phenolates

2011

The reaction of WOCl(4) with 2,4-di-tert-butyl-6-((isopropylamino)methyl)phenol followed by the reaction with phenyl isocyanate leads to the formation of imidotungsten(VI) complex [W(NPh)Cl(3)(OC(6)H(3)(CH(2)NH-i-Pr)-2-t-Bu(2)-4,6)] 4 with a chelating aminophenolate ligand. When the same procedure was applied using aminophenols with bulkier substituents in the amino group, the final product was an unexpected Schiff-base complex [W(NPh)Cl(3)(OC(6)H(3)(CH=NPh)-2-t-Bu(2)-4,6)] 5, where the ligand is derived from 2,4-di-tert-butyl-6-((phenylimino)methyl)phenol. Complex 5 is also formed in the thermal degradation of 4. On the whole, 5 appears to be formed by a disproportionation of intermediate …

Low-Dimensional 3d–4f Complexes Assembled by Low-Spin [FeIII(phen)(CN)4]− Anions

2013

The synthesis, crystal structure, and magnetic properties of four new mixed 3d-4f complexes with formulas [{FeIII(phen)(CN)4} 4Gd2 III(bpym)(NO3) 2(H2O)4]·2CH3CN· 2H2O}n (1), [{FeIII(phen)(CN)4} 4Tb2 III(bpym)(H2O) 8]·(NO3)2·2CH3CN} n (2), [{FeIII(phen)(CN)4}4Sm III(bpym)(NO3)2(H2O) 5]·2CH3CN}n (3), and [{Fe III(phen)(CN)4}2Pr2 III(bpym)(NO3)4(H2O) 2]n (4) (phen = 1,10-phenanthroline and bpym = 2,2′-bipyrimidine) are discussed here. Compounds 1-3 are isomorphous and their structure consists of neutral ladder-like motifs where the rungs are made up by bpym-bridged dilanthanide(III) cations and the rods are defined by [Fe(phen)(CN)4]- units adopting a bis-monodentate coordination mode through…

Improving survival with deferiprone treatment in patients with thalassemia major: A prospective multicenter randomised clinical trial under the auspi…

2009

The prognosis for thalassemia major has dramatically improved in the last two decades. However, many transfusion-dependent patients continue to develop progressive accumulation of iron. This can lead to tissue damage and eventually death, particularly from cardiac disease. Previous studies that investigated iron chelation treatments, including retrospective and prospective non-randomised clinical trials, suggested that mortality, due mainly to cardiac damage, was reduced or completely absent in patients treated with deferiprone (DFP) alone or a combined deferiprone-deferoxamine (DFP-DFO) chelation treatment. However, no survival analysis has been reported for a long-term randomised control …

Le pur, l'impur et l'imaginaire des éléments chez Bachelard

2011

International audience

Michelangelon veistämisen muotokielen yhtäläisyyksistä eri mediumeissa - taiteenala mediumina

2007

Iron oxides nanoparticles and titanate nanotubes dedicated to multimodal imaging and anticancer therapy

2013

The new implementations of nanoparticles in the medical field are one of the essential factors of the medical progress expected at the beginning of this XXIst century. Thus, the domain of the medical imaging is also affected by this technological evolution. This work consisted in developing theranostic probes with iron oxides nanoparticles (SPIO) and titanate nanotubes (TiONts) for multimodal imaging (magnetic/nuclear or magnetic/optical) and also possessing a therapeutic effect (hyperthermia/PDT or radiosensitization/PDT).The titanate nanotubes of this study have an average length of about 150 nm and were obtained by Kasuga's hydrothermal synthesis. These nanotubes present an outside diame…

Interaction of Dimethyltin(IV)2+ Cation with Gly-Gly, Gly-His, and Some Related Ligands. A New Case of a Metal Ion Able To Promote Peptide Nitrogen D…

1999

Equilibrium (pH-metric) and spectroscopic (1H,13C, and 119Sn NMR and 119Sn Mossbauer) studies were performed to characterize the interaction of the dimethyltin(IV) cation with glycine, glycyl-glycine (Gly-Gly), imidazole-4-acetic acid, histamine, histidine, glycyl-histamine, glycyl-histidine (Gly-His), and β-alanyl-histidine (carnosine). For histamine and glycyl-histamine (having only nitrogen donor atoms) no complex formation was detected. The hydrolyzed species of the dimethyltin(IV) cation are always dominant over the complexes formed with the other ligands, except with Gly-Gly and Gly-His. For these two ligands, {COO-,N-,NH2} coordinated complexes are dominant in the neutral pH range wi…

Sequestering ability of polyaminopolycarboxylic ligands towards dioxouranium(VI) cation

2006

Abstract In the present paper, some results of an investigation (at t = 25 °C by potentiometry, ISE-H+ glass electrode) on the sequestering ability of five different polyaminopolycarboxylic ligands [Nitrilotriacetate (NTA), ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetate (EGTA), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA), triethylenetetraamine-N,N,N′,N″,N′′′,N′′′-hexaacetate (TTHA)] towards dioxouranium(VI) cation in sodium chloride aqueous solutions, at I = 0.7 mol L−1 are reported. Calculations performed on potentiometric data gave evidence of the formation of the following species (log β in parenthesis): UO2(NTA)H0 (12…