Search results for "Chiral"

showing 10 items of 752 documents

Hexagonal Microparticles from Hierarchical Self-Organization of Chiral Trigonal Pd3L6 Macrotetracycles

2021

Construction of structurally complex architectures using inherently chiral, asymmetric, or multi-heterotopic ligands is a major challenge in metallosupramolecular chemistry. Moreover, the hierarchical self-organization of such complexes is unique. Here, we introduce a water-soluble, facially amphiphilic, amphoteric, chiral, asymmetric, and hetero-tritopic ligand derived from natural bile acid, ursodeoxycholic acid. We show that via the supramolecular transmetalation reaction, using nitrates of Cu(II) or Fe(III), and subsequently Pd(II), a superchiral Pd3L6 complex can be obtained. Even though several possible constitutional isomers of Pd3L6 could be formed, because of the ligand asymmetry a…

particlesurfactantSupramolecular chemistryGeneral Physics and Astronomychemistry.chemical_elementchirality02 engineering and technology010402 general chemistry01 natural sciences114 Physical sciencessupramolecular chemistryTransmetalationPhysico-chimie généraleChimie des colloïdesAmphiphileStructural isomersupramolekulaarinen kemiaChimiebile acidGeneral Materials ScienceLigandChemistryGeneral Engineeringheterotopic ligandChimie des surfaces et des interfacesGeneral Chemistrykompleksiyhdisteetself-assembly021001 nanoscience & nanotechnologypalladiumself-organization0104 chemical sciences3. Good healthmikrorakenteetCrystallographyChimie organiqueGeneral EnergytransmetalationSelf-assembly0210 nano-technologyChirality (chemistry)Palladium
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Asymmetric hysteresis for probing Dzyalohsinskii-Moriya interaction

2016

The interfacial Dzyaloshinskii-Moriya interaction (DMI) is intimately related to the prospect of superior domain-wall dynamics and the formation of magnetic skyrmions. Although some experimental efforts have been recently proposed to quantify these interactions and the underlying physics, it is still far from trivial to address the interfacial DMI. Inspired by the reported tilt of the magnetization of the side edge of a thin film structure, we here present a quasi-static, straightforward measurement tool. By using laterally asymmetric triangular-shaped microstructures, it is demonstrated that interfacial DMI combined with an in-plane magnetic field yields a unique and significant shift in m…

perpendicular magnetic anisotropyNucleationFOS: Physical sciencesBioengineering02 engineering and technology01 natural sciencesMagnetization0103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)General Materials Sciencechiral magnetThin film010306 general physicsPhysicsDzyaloshinskii-Moriya interactionspintronicsCondensed Matter - Materials ScienceCondensed Matter - Mesoscale and Nanoscale PhysicsSpintronicsCondensed matter physicsMechanical EngineeringSkyrmionMaterials Science (cond-mat.mtrl-sci)General Chemistry021001 nanoscience & nanotechnologyCondensed Matter PhysicsMagnetic hysteresisMagnetic fieldHysteresisnanomagnetism0210 nano-technologyasymmetric hysteresis loopNano Letters
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Designing P-Chirogenic 1,2-Diphosphinobenzenes at Both P-Centers Using P(III)-Phosphinites

2016

International audience; A new enantiodivergent synthesis of P-chirogenic 1,2-diphosphinobenzenes (DP*B) bearing the chirality on one or both phosphorus centers is reported using aryne chemistry. The principle is based on successive reactions of 1,2-dibromobenzene with sec-phosphide boranes, then DABCO to remove the borane, and finally with chlorophosphines or P(III)-chirogenic phosphinites. The efficiency of this synthesis was demonstrated by the stereoselective preparation of (S,S)-1,2-bis(o-anisylphenylphosphino)benzene. A comparison of DIPAMP and homochiral DP*B ligands in asymmetric Rh- or Pd-catalyzed reactions was reported.

phosphine-ligandsDIPAMPketonesStereochemistryBoranesDABCOBorane010402 general chemistry[ CHIM ] Chemical Sciences01 natural sciencesBiochemistryArynecatalyzed asymmetric hydrogenationchemistry.chemical_compoundfunctionalized alkenes[ CHIM.ORGA ] Chemical Sciences/Organic chemistry[CHIM]Chemical SciencesorganocatalysisPhysical and Theoretical Chemistryhydroformylation010405 organic chemistryChemistry[CHIM.ORGA]Chemical Sciences/Organic chemistryOrganic Chemistrycarbon-monoxide0104 chemical scienceshighly enantioselective hydrogenationOrganocatalysisderivativesStereoselectivityChirality (chemistry)phospholane ligands
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Pion photo- and electroproduction on nucleons in relativistic chiral perturbation theory

2022

En esta tesis, hemos estudiado la producción de piones mediante pruebas electromagnéticas en nucleones. Para cada uno de los estudios realizados aquí, nos enfocamos en la Teoría Quiral de Perturbaciones (ChPT) relativista para hadrones ligeros: nucleones, piones y los grados de libertad explícitos Delta. Para preservar la covariancia de la teoría, se implementó el método de renormalización en el esquema Extended On Mass Shell (EOMS). En este caso, las divergencias y los términos que violan el conteo de potencias se absorben en las constantes de baja energía (LECs) del Lagrangiano efectivo. El presente trabajo se desarrolló dentro de tres estudios principales relacionados con la producción d…

pion photoproduction on nucleipion photoproduction on nucleonsUNESCO::FÍSICAlow energy hadron dynamicschiral perturbation theory
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Amino acid-­deriving chiral polymers with potential for biotechnological applications

2017

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poly(amidoamine)s chiral polymers interpenetrating peptides
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First observation and study of the K± → π±π0e+e− decay

2018

The NA48/2 experiment at CERN reports the first observation of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay from an exposure of 1.7 x 10(11) charged kaon decays recorded in 2003-2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region, BR(K-+/- -> pi(+/-)pi(0)e(+)e(-)) = (4.24 +/- 0.14) x 10(-6). The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.

rare decayNuclear and High Energy PhysicsChiral perturbation theoryCP violation; Monte-Carlo; searchAstronomy & AstrophysicsSpace (mathematics)quark mixing01 natural sciencesPartícules (Física nuclear)Charged Kaon decaysPhysics Particles & FieldsCharged Kaon decays quark mixing radiative kaon decay chiral perturbation theoryEconomica0202 Atomic Molecular Nuclear Particle And Plasma PhysicsViolació CP (Física nuclear)MONTE-CARLOSEARCH0103 physical sciencesKaon decaysradiative kaon decay010306 general physicsPhysicsScience & Technology010308 nuclear & particles physicsBranching fractionPhysicsKaon decays Chiral Perturbation TheoryAmbientaleK mesonNuclear & Particles PhysicsChiral Perturbation Theorylcsh:QC1-999fixed target experimentPhysics NuclearPhysical SciencesK meson rare decay fixed target experimentCP violationHigh Energy Physics::ExperimentCP VIOLATIONAtomic physicslcsh:PhysicsPhysics Letters B
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Role of the N-*(1535) in the J/psi -> pp and J/psi -> p(+)Lambda reactions

2009

We study the J/psi -> p eta p and J/psi -> pK(+)Lambda reactions with a unitary chiral approach. We find that the unitary chiral approach, which generates the N-*(1535) dynamically, can describe the data reasonably well, particularly the ratio of the integrated cross sections. This study provides further support for the unitary chiral description of the N-*(1535). We also discuss some subtle differences between the coupling constants determined from the unitary chiral approach and those determined from phenomenological studies

ratio [width]High Energy Physics::LatticeJ/psi(3100) --> p anti-p etaJ/psi(3100) --> Lambda anti-p K+Físicahadronic decay [J/psi(3100)]coupling constant [N(1535)]mass spectrumwidth [J/psi(3100)]unitarityddc:530chiral [effective Lagrangian]numerical calculations
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Chirality selective spin interactions mediated by the moving superconducting condensate

2018

We show that superconducting correlations in the presence of nonzero condensate velocity can mediate the peculiar interaction between localized spins that breaks the global inversion symmetry of magnetic moments. The proposed interaction mechanism is capable of removing fundamental degeneracies between topologically distinct magnetic textures. For the generic system of three magnetic impurities in the current-carrying superconductor, we find the energy term proportional to spin chirality. In realistic superconductor/ferromagnetic/superconductor setups we reveal significant energy differences between various magnetic textures with opposite chiralities. We calculate Josephson energies of junc…

suprajohtavuusskyrmionsmagnetic textureexchange interaction02 engineering and technology01 natural sciencessuprajohteetCondensed Matter::Superconductivityimpurities in superconductors0103 physical sciencesmagnetismi010306 general physicsSpin (physics)RKKY interactionPhysicsSuperconductivityMagnetic momentSpintronicsCondensed matter physicsSpinsta114SkyrmionJosephson effect021001 nanoscience & nanotechnologyChirality (electromagnetism)Ferromagnetismhelicoidal magnetic texture0210 nano-technologymagnetic vorticesPhysical Review B
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Total Structure and Electronic Structure Analysis of Doped Thiolated Silver [MAg24(SR)18]2– (M = Pd, Pt) Clusters

2015

With the incorporation of Pd or Pt atoms, thiolated Ag-rich 25-metal-atom nanoclusters were successfully prepared and structurally characterized for the first time. With a composition of [PdAg24(SR)18](2-) or [PtAg24(SR)18](2-), the obtained 25-metal-atom nanoclusters have a metal framework structure similar to that of widely investigated Au25(SR)18. In both clusters, a M@Ag12 (M = Pd, Pt) core is capped by six distorted dimeric -RS-Ag-SR-Ag-SR- units. However, the silver-thiolate overlayer gives rise to a geometric chirality at variance to Au25(SR)18. The effect of doping on the electronic structure was studied through measured optical absorption spectra and ab initio analysis. This work d…

ta114ChemistryStereochemistryDopingAb initioGeneral ChemistryElectronic structureengineering.materialpalladiumBiochemistryCatalysissilver nanoclustersNanoclustersCatalysisOverlayerCrystallographyColloid and Surface ChemistryengineeringNoble metalplatinumChirality (chemistry)ta116thiolsJournal of the American Chemical Society
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Electronic Structure and Optical Properties of the Intrinsically Chiral 16-Electron Superatom Complex [Au20(PP3)4]4+

2014

The recently solved crystal structure of the [Au20(PP3)4]Cl4 cluster (PP3: tris(2-(diphenylphophino)ethyl)phosphine) is examined using density functional theory (DFT). The Au20 core of the cluster is intrinsically chiral by the arrangement of the Au atoms. This is in contrast to the chirality of thiolate-protected gold clusters, in which the protecting Au-thiolate units are arranged in chiral patterns on achiral cores. We interpret the electronic structure of the [Au20(PP3)4]Cl4 cluster in terms of the superatom complex model. The 16-electron cluster cannot be interpreted as a dimer of 8-electron clusters (which are magic). Instead, a superatomic electron configuration of 1S(2) 1P(6) 1D(6) …

ta114Condensed matter physicsAbsorption spectroscopyChemistrySuperatomCrystal structureElectronic structureCrystallographyCluster (physics)Density functional theoryElectron configurationPhysical and Theoretical ChemistryChirality (chemistry)ta116The Journal of Physical Chemistry A
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