Search results for "cyclic"
showing 10 items of 2439 documents
Fe(III)-DOTA/Fe(III)-NOTA Complexes: Attractive Alternative Markers for Future Electrochemical Biosensors
2020
Metallic complexes of macrocycles chelators 1,4,7-triazacyclononane-N,N,N-triacetic acid (NOTA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) were synthetized with iron (III) giving Fe(III)-DOTA and Fe(III)-NOTA complexes. They were studied in comparison of ferricyanide and ferrocenemethanol on cyclic voltammetry with glassy carbon working electrode (GC) and screen-printed carbon electrode (SPCE). Diffusion coefficients and heterogeneous electron transfer rate constants were determined with Randles-Sevcik and Nicholson-Lavagnini methods. Using SPCE. The average values of diffusion coefficient and transfer rate constant were respectively of 1.34 × 10−6 cm2 s−1 and 1.01 …
Methyl 3,3,6,6-tetramethyl-1,8-dioxo-4,5,7,9-tetrahydro-2H-xanthene-9-carboxylate
2020
The title molecule, C19H24O5, is built by annulation of a half-chair cyclohexenone and a twist-cyclohexenone to a flat 4-H-pyrane boat. In the crystal, molecules are connected via van der Waals interactions and C—H...O hydrogen bonds.
Synthesis and high-throughput testing of multilayered supported ionic liquid catalysts for the conversion of CO2 and epoxides into cyclic carbonates
2014
Multilayered covalently supported ionic liquid phase (mlc-SILP) materials were synthesised by grafting different bis-vinylimidazolium salts on thiol-functionalised silica. These materials, which contain a cross-linked oligomeric network of imidazolium units, were characterised and tested as catalysts for the reaction of carbon dioxide with various epoxides to produce cyclic carbonates. The materials prepared by supporting a bis-imidazolium iodide salt with xylene or octane as a linker between the imidazolium units were identified as the most active catalysts and displayed high turnover numbers and improved productivity compared to known supported ionic liquid catalysts. The most promising m…
Evaluation of Fused Pyrrolothiazole Systems as Correctors of Mutant CFTR Protein.
2021
Cystic fibrosis (CF) is a genetic disease caused by mutations that impair the function of the CFTR chloride channel. The most frequent mutation, F508del, causes misfolding and premature degradation of CFTR protein. This defect can be overcome with pharmacological agents named “correctors”. So far, at least three different classes of correctors have been identified based on the additive/synergistic effects that are obtained when compounds of different classes are combined together. The development of class 2 correctors has lagged behind that of compounds belonging to the other classes. It was shown that the efficacy of the prototypical class 2 corrector, the bithiazole corr-4a, could be impr…
Polyamines and applications. A look at the first workshop in linear and cyclic polyamines chemistry
2008
Given their versatile coordination properties, cyclic and linear polyamines are the subject of numerous worksin many research groups. This great interest is mainly related to their use in diverse fields such as removalof metals from liquids, purification of gases, application in catalysis, in sensors, as well as in various probesfor medical applications. This paper summarizes recent results obtained by the French research groupswhich attended the first ìworkshop in linear and cyclic polyamines chemistryî.
“Two-Story” Calix[6]arene-Based Zinc and Copper Complexes: Structure, Properties, and O 2 Binding
2017
International audience; A new “two-story” calix[6]arene-based ligand was synthesized, and its coordination chemistry was explored. It presents a tren cap connected to the calixarene small rim through three amido spacers. X-ray diffraction studies of its metal complexes revealed a six-coordinate ZnII complex with all of the carbonyl groups of the amido arms bound and a five-coordinate CuII complex with only one amido arm bound. These dicationic complexes were poorly responsive toward exogenous neutral donors, but the amido arms were readily displaced by small anions or deprotonated with a base to give the corresponding monocationic complexes. Cyclic voltammetry in various solvents showed a r…
Presentations of constrained systems with unconstrained positions
2005
International audience; We give a polynomial-time construction of the set of sequences that satisfy a finite-memory constraint defined by a finite list of forbidden blocks, with a specified set of bit positions unconstrained. Such a construction can be used to build modulation/error-correction codes (ECC codes) like the ones defined by the Immink-Wijngaarden scheme in which certain bit positions are reserved for ECC parity. We give a lineartime construction of a finite-state presentation of a constrained system defined by a periodic list of forbidden blocks. These systems, called periodic-finite-type systems, were introduced by Moision and Siegel. Finally, we present a linear-time algorithm for con…
New applications of graded Lie algebras to Lie algebras, generalized Lie algebras and cohomology
2007
We give new applications of graded Lie algebras to: identities of standard polynomials, deformation theory of quadratic Lie algebras, cyclic cohomology of quadratic Lie algebras, $2k$-Lie algebras, generalized Poisson brackets and so on.
Morphological and chemical dynamics upon electrochemical cyclic sodiation of electrochromic tungsten oxide coatings extracted by in situ ellipsometry.
2020
The sodiation–desodiation process of sputtered amorphous electrochromic tungsten oxide coatings in an aqueous-based medium was simultaneously monitored over 99 cycles by cyclic voltammetry and in situ spectroscopic ellipsometry. This allowed extracting the evolution of optical and geometrical parameters upon cycling. The resulting electrochemical coloring-bleaching process was dynamically fitted in the 1.8–2.8 eV optical range with a four-phase model including a constrained spline parametrization of the dielectric function. This allows real time access to thickness, surface roughness, and dielectric function of N a x W O 3 . The temporal evolution of the latter in the fully colored state wa…
A Study Using X-ray Absorption and Emission Spectroscopy of Dioxygen-Binding Xerogels Incorporating Cyclam Units Complexed with Copper Salts.
2005
X-ray absorption spectroscopy was used to elucidate how hybrid xerogels complexed with CuCl2 could reversibly bind molecular dioxygen. Difference EXAFS analyses at the Cu K-edge suggest that dioxygen could bridge two Cu atoms in a μ-η1:η1 peroxo-like conformation with unequal Cu···O distances. Only the short distance (RCu–O1 = 1.86 ± 0.01 A) was unambiguously determined and looks typical of a CuII site. The Cu···Cu internuclear distances would be rather long: RCu–Cu ≈ 4.0 A (3.9 A) for the oxygenated (oxygen-free) xerogels. Cl K-edge EXAFS spectra revealed the pre-existence in the oxygen-free xerogels of CuI sites with short Cl–Cu bonds (2.11 ± 0.03 A). Pentacoordinate CuII sites with a lon…