Search results for "Lanthanide Complexes"

showing 3 items of 3 documents

Direct detection of 17O NMR in [Gd(DOTA)]- by NMR Spectroscopy

2015

The 17O NMR spectrum of the non-coordinated carboxyl oxygen in the GdIII-DOTA (DOTA = tetraazacyclododecanetetraacetic acid) complex has been observed experimentally. Its line width is essentially unaffected by paramagnetic relaxation due to gadolinium, and is only affected by the quadrupole pathway. The results are supported by the relevant parameters (hyperfine and quadrupole coupling constants) calculated by relativistic DFT methods. This finding opens up new avenues for investigating the structure and reactivity of paramagnetic GdIII complexes used as contrast agents in magnetic resonance imaging.

lanthanide complexesLanthanideGadoliniumchemistry.chemical_elementImaging agentsCatalysisNMR spectroscopy; Density functional calculations; lanthanide complexes; gadolinium; O-17 nmrParamagnetismchemistry.chemical_compoundNMR spectroscopyNuclear magnetic resonanceLanthanidesDOTAHyperfine structureChemistryOrganic ChemistryRelaxation (NMR)General ChemistryNuclear magnetic resonance spectroscopyDensity functional calculationsSettore CHIM/03 - Chimica Generale E InorganicaQuadrupole17O NMR Lanthanides DFTCondensed Matter::Strongly Correlated ElectronsgadoliniumO-17 nmr
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Lanthanum-pyBOX complexes as catalysts for the enantioselective conjugate addition of malonate esters to β,γ-unsaturated α-ketimino esters

2018

[EN] In this paper, we report the application of chiral complexes of La(III) with pyBOX ligands as Lewis acid catalysts in the conjugate addition of malonic esters to N-tosyl imines derived from ß,gamma-unsaturated alfa-keto esters to give the corresponding chiral alfa,ß-dehydroamino esters. pyBOX complexes with La(III), Yb(III), Sc(III), and In(III) triflates were assessed in this reaction but only La(III) showed good activity and enantioselectivity, while Yb(III) provided the expected product with low yield and stereoselectivity, and the Sc(III) and In(III) complexes were completely inactive. The complex of La(OTf)3 with the diphenyl-pyBOX ligand prepared in situ provided the best results…

Double bondEnantioselectivity010402 general chemistry01 natural sciencesMedicinal chemistrychemistry.chemical_compoundCatàlisiMichael additionAsymmetric catalysisMaterials ChemistryLewis acids and basesPhysical and Theoretical Chemistrychemistry.chemical_classification010405 organic chemistryDiastereomerEnantioselective synthesisLanthanide complexes0104 chemical sciencesMalonatechemistryFISICA APLICADAMichael reactionStereoselectivityEnantiomerQuímica orgànica
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Syntheses, Structures, Magnetic Properties, and Density Functional Theory Magneto-Structural Correlations of Bis(μ-phenoxo) and Bis(μ-phenoxo)-μ-acet…

2013

The bis(mu-phenoxo) (FeNiIII)-Ni-II compound [Fe-III(N-3)(2)LNiII(H2O)(CH3CN)](ClO4) (1) and the bis(mu-phenoxo)-mu-acetate/bis(mu-phenoxo)-bis(mu-acetate) (FeNiII)-Ni-III compound {[Fe-III(OAc)LNiII(H2O)(mu-OAc)](0.6)center dot[(FeLNiII)-L-III(mu-OAc)(2)](0.4)}(ClO4)center dot 1.1H(2)O (2) have been synthesized from the Robson type tetraiminodiphenol macrocyclic ligand H2L, which is the [2 + 2] condensation product of 4-methyl-2,6-diformylphenol and 2,2'-dimethy1-1,3-diaminopropane. Single-crystal X-ray structures of both compounds have been determined. The cationic part of the dinuclear compound 2 is a cocrystal of the two species [Fe-III(OAc)LNiII(H2O)(mu-OAc)](+) (2A) and [(FeLNiII)-L-I…

Coordination ClustersCopper(Ii) ComplexesSingle-Molecule MagnetTransition-Metal-ComplexesChemistryStereochemistryTheoretical ExplorationExchange InteractionsCationic polymerizationCocrystalAnisotropy BarrierInorganic ChemistryCrystallographyFerromagnetismAntiferromagnetismLanthanide ComplexesDensity functional theoryMacrocyclic ligandPhysical and Theoretical ChemistrySpin Ground-StateGaussian-Basis SetsInorganic Chemistry
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