74 results match your criteria: "UMR 6509 CNRS-Université de Rennes[Affiliation]"

Hydrogen-iodine scattering. II. Rovibronic analysis and collisional dynamics.

J Chem Phys

July 2024

Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, F-35000 Rennes, France.

Our recently published [Weike et al., J. Chem.

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The scattering of H by I is a prototypical model system for light-heavy scattering in which relativistic coupling effects must be taken into account. Scattering calculations depend strongly on the accuracy of the potential energy surface (PES) model. The methodology to obtain such an accurate PES model suitable for scattering calculations is presented, which includes spin-orbit (SO) coupling within the Effective Relativistic Coupling by Asymptotic Representation (ERCAR) approach.

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Background:  Although a growing number of very elderly patients with atrial fibrillation (AF), multiple conditions, and polypharmacy receive direct oral anticoagulants (DOACs), few studies specifically investigated both apixaban/rivaroxaban pharmacokinetics and pharmacodynamics in such patients.

Aims:  To investigate: (1) DOAC concentration-time profiles; (2) thrombin generation (TG); and (3) clinical outcomes 6 months after inclusion in very elderly AF in-patients receiving rivaroxaban or apixaban.

Methods:  Adage-NCT02464488 was an academic prospective exploratory multicenter study, enrolling AF in-patients aged ≥80 years, receiving DOAC for at least 4 days.

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Background: Rivaroxaban is a direct factor Xa inhibitor with substantial inter-individual pharmacokinetic (PK) variability. Pharmacodynamic (PD) variability, especially assessed with thrombin generation (TG), has been less documented.

Objectives: (i) To assess TG parameter time profiles in healthy volunteers, with TG being studied under different conditions and (ii) to model the relationship between rivaroxaban concentrations and TG parameters and subsequently estimate interindividual variability.

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Glioblastoma, an aggressive brain tumor, has a poor prognosis and a high risk of recurrence. An improved chemotherapeutic approach is required to complement radiation therapy. Gold(I) complexes bearing phosphole ligands are promising agents in the treatment of cancer and disturb the redox balance and proliferation of cancer cells by inhibiting disulfide reductases.

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The allenylidene-ruthenium complexes [(eta6-arene)RuCl(=C=C=CR2)(PR'3)]OTf (R2 = Ph; fluorene, Ph, Me; PR'3 = PCy3, P(i)Pr3, PPh3) (OTf = CF3SO3) on protonation with HOTf at -40 C are completely transformed into alkenylcarbyne complexes [(eta6-p-cymene)RuCl([triple bond]CCH=CR2)(PR3)](OTf)2. At -20 degrees C the latter undergo intramolecular rearrangement of the allenylidene ligand, with release of HOTf, into the indenylidene group in derivatives [(eta6-arene)RuCl(indenylidene)(PR3)]OTf. The in situ-prepared indenylidene-ruthenium complexes are efficient catalyst precursors for ring-opening metathesis polymerization of cyclooctene and cyclopentene, reaching turnover frequencies of nearly 300 s(-1) at room temperature.

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Metal vinylidenes and allenylidenes in catalysis: applications in anti-Markovnikov additions to terminal alkynes and alkene metathesis.

Angew Chem Int Ed Engl

March 2006

Institut de Chimie, UMR 6509, CNRS-Université de Rennes 1, Organométalliques et Catalyse: Chimie et Electrochimie Moléculaires, Campus de Beaulieu, 35042 Rennes Cedex, France.

The involvement of a catalytic metal vinylidene species was proposed for the first time in 1986 to explain the regioselective formation of vinyl carbamates directly from terminal alkynes, carbon dioxide, and amines. Since this initial report, various metal vinylidenes and allenylidenes, which are key activation intermediates, have proved extremely useful for many alkyne transformations. They have contributed to the rational design of new catalytic reactions.

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Photoisomerizable bipyridine ligands and macroligands: absorption, photoisomerization properties and theoretical study.

Chemphyschem

March 2006

Organométalliques et Catalyse: Chimie et Electrochimie Moléculaires, UMR 6509 CNRS-Université de Rennes 1, Institut de Chimie de Rennes, Campus de Beaulieu, 35042 Rennes Cedex, France.

Two 2,2'-bipyridines, substituted at the 4,4'-positions by p-dialkylaminophenylazostyryl moieties p-R2N-C6H4-N=N-C6H4-CH=CH-[6 a, R2N=nBu2N; 6 b, R2N=(nBu)(C4H8OTHP)N; 6 c, R2N=(nBu)(C4H8OH)N], were successfully synthesized by using Wadworth-Emmons reactions. The X-ray structure of 6 a has been determined. Esterification of 6 c with 2-bromoisobutyroylbromide afforded 6 d.

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The synthesis and study of a new redox family of symmetric dinuclear iron(II/III) complexes featuring "(eta(2)-dppe)(eta(5)-C(5)Me(5))Fe(CC)" endgroups connected by a bis(diethynyl)-4,4'-biphenyl spacer are reported. The solid-state structures were determined (X-rays) for the homovalent Fe(II)/Fe(II) and Fe(III)/Fe(III) parents. In contrast, the mixed valent (MV) complex 5[PF(6)] has a low thermodynamic stability (Kc around 10) and cannot be isolated in a pure form, but was studied in solution.

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O2 and CO binding to tetraaza-tripodal-capped iron(II) porphyrins.

Inorg Chem

February 2006

Université de Rennes 1, Institut de Chimie, UMR CNRS 6509, Organométalliques et Catalyse, Chimie et Electrochimie Moléculaire, 35042 Rennes Cedex, France.

A series of tris(2-aminoethylamine) (tren) capped iron(II) porphyrins has been synthesized and characterized and their affinities for dioxygen and carbon monoxide measured. The X-ray structure of the basic scaffold with nickel inserted in the porphyrin is also reported. All the ligands differ by the nature of the group(s) attached to the secondary amine functions of the cap.

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A series of new alkoxy-amino-bis(phenols) (H2L 1-6) has been synthesized by Mannich condensations of substituted phenols, formaldehyde, and amino ethers or diamines. The coordination properties of these dianionic ligands towards yttrium, lanthanum, and neodymium have been studied. The resulting Group 3 metal complexes have been used as initiators for the ring-opening polymerization of rac-lactide to provide poly(lactic acid)s (PLAs).

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Lanthanide complexes for second order nonlinear optics: evidence for the direct contribution of f electrons to the quadratic hyperpolarizability.

J Am Chem Soc

October 2005

Organométalliques et Catalyse, UMR 6509 CNRS - Université de Rennes 1, Groupe de la Matière Condensée, UMR 6626, Institut de Chimie de Rennes, Campus de Beaulieu, 35042 Rennes, France.

This study descibes for the first time the nonlinear optical (NLO) properties of multipolar lanthanide complexes, Na3[Ln(dipic)3]. The "metal-induced" NLO activity enhancement is confirmed as a general property of f-block elements, and the direct participation of f electrons to the hyperpolarizability beta is strongly supported by experimental data.

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The regioselective head-to-head [2 + 2] cyclodimerization of allenyl boronate catalyzed by the ruthenium catalyst [Cp*RuCl(COD)] leads to a novel diboronated 1,3-dimethylenecyclobutane. Consecutive palladium-catalyzed C-C couplings open a route to novel disubstituted 1,3-dimethylenecyclobutane species. The X-ray crystalline structure of the phenyl-substituted 1,3-dimethylenecyclobutane is provided.

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The reaction of diazo compounds with enynes, containing a fluorinated amino acid moiety, in the presence of the precatalyst Cp(Cl)Ru(COD) leads to fluorinated alkenyl bicyclo[3.1.0]hexane and [4.

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Naked eye detection of anions by alkynyl-ruthenium exo-receptors: selective recognition of fluoride anion.

Chem Commun (Camb)

June 2005

Institut de Chimie de Rennes, Laboratoire Organometalliques et Catalyse: Chimie et Electrochimie Moleculaires, UMR 6509 CNRS, Universite de Rennes 1, Campus de Beaulieu, 35042, Rennes cedex, France.

Alkynyl-ruthenium complexes bearing terminal hydrogen-bonding receptors act as efficient anion sensors exhibiting large guest-induced colour changes and show unexpectedly high selectivity to fluoride ions.

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The stability of a graphite felt electrode modified by covalent attachment of [Ru(II)(tpy)(bpy)(OH(2))](2+) is investigated during the indirect electrolyses of alcohols in a flow cell. The continuous increase of the local potential of the electrode during the electrolyses attests to its degradation. Cyclic voltammetry analyses of the modified electrode after electrolyses show a total decrease of 80-90% of the wave corresponding to the Ru(III/II) couple.

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Electrophilic activation and cycloisomerization of enynes: a new route to functional cyclopropanes.

Angew Chem Int Ed Engl

April 2005

Institut de Chimie, UMR 6509: CNRS-Université de Rennes 1, Organométalliques et Catalyse, Rennes Cedex, France.

Transformations of enynes in the presence of transition-metal catalysts have played an important role in the preparation of a variety of cyclic compounds. Recent developments in the activation of triple carbon-carbon bonds by electrophilic metal centers have provided a new entry to the selective synthesis of cyclopropane derivatives from enynes. The mechanisms of these reactions involve catalytic species with both ionic and cyclopropylcarbenoid character.

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The reaction of propargylic alcohols with carboxylic acid, or phenol derivatives, in the presence of the precatalyst [RuCl(cod)(C5Me5)] leads selectively to a variety of alkylidenecyclobutenes through head-to-head dimerization of propargylic alcohol. The first step is the formation of a cyclobutadiene-ruthenium intermediate resulting from the head-to-head coupling of two molecules of propargylic alcohol. On protonation with strong acids (HPF6, HBF4) dehydration of the cyclobutadiene complex leads to formation of an alkylidenecyclobutenyl-ruthenium complex.

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First lanthanide dipolar complexes for second-order nonlinear optics.

Chem Commun (Camb)

October 2004

Organométalliques et Catalyse: Chimie et Electrochimie Moléculaires, UMR 6509 CNRS-Université de Rennes 1, Institut de Chimie de Rennes, Campus de Beaulieu, 35042 Rennes Cedex, France.

New push-pull NLO-phores based on lanthanide complexes (Ln = La, Gd, Dy, Yb) featuring an annelated dibutylaminophenyl functionalised terpyridyl ligand have been synthesised and shown to exhibit large first-order hyperpolarizability.

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Allylic complexes of lanthanides bearing a fluorenyl-based ligand are active single-component catalysts for the polymerization of styrene, giving highly syndiotactic polymers (rrrr > 99%) with low to high molecular weight (Mn = 8000-135 000) and narrow polydispersities (Mw/Mn = 1.25-2.1).

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Synthesis, linear, and quadratic-nonlinear optical properties of octupolar D3 and D2d bipyridyl metal complexes.

Chemistry

September 2004

Organométalliques et Catalyse, Chimie et Electrochimie Moléculaires, UMR 6509 CNRS-Université de Rennes 1, Institut de Chimie de Rennes, Campus de Beaulieu, 35042 Rennes Cedex, France.

A series of D3 (Fe(II), Ru(II), Zn(II), Hg(II)) and D2d (Cu(I), Ag(I), Zn(II)) octupolar metal complexes featuring different functionalized bipyridyl ligands has been synthesized, and their thermal, linear (absorption and emission), and nonlinear optical (NLO) properties were determined. Their quadratic NLO susceptibilities were determined by harmonic light scattering at 1.91 microm, and the molecular hyperpolarizability (beta0) values are in the range of 200-657 x 10(-30) esu for octahedral complexes and 70-157 x 10(-30) esu for tetrahedral complexes.

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