0000000000375854

AUTHOR

Barbara Ripka

showing 4 related works from this author

Geminal Parahydrogen-Induced Polarization: Accumulating Long-Lived Singlet Order on Methylene Proton Pairs

2020

In the majority of hydrogenative parahydrogen-induced polarization (PHIP) experiments, the hydrogen molecule undergoes pairwise cis addition to an unsaturated precursor to occupy vicinal positions on the product molecule. However, some ruthenium-based hydrogenation catalysts induce geminal hydrogenation, leading to a reaction product in which the two hydrogen atoms are transferred to the same carbon centre, forming a methylene (CH2) group. The singlet order of parahydrogen is substantially retained over the geminal hydrogenation reaction, giving rise to a singlet-hyperpolarized CH2 group. Although the T1 relaxation times of the methylene protons are often short, the singlet order has a long…

inorganic chemicals
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Towards Large-Scale Steady-State Enhanced Nuclear Magnetization with In Situ Detection

2021

Signal Amplification By Reversible Exchange (SABRE) boosts NMR signals of various nuclei enabling new applications spanning from magnetic resonance imaging to analytical chemistry and fundamental physics. SABRE is especially well positioned for continuous generation of enhanced magnetization on a large scale, however, several challenges need to be addressed for accomplishing this goal. Specifically, SABRE requires (i) a specialized catalyst capable of reversible H2 activation and (ii) physical transfer of the sample from the point of magnetization generation to the point of detection (e.g., a high-field or a benchtop NMR spectrometer). Moreover, (iii) continuous parahydrogen bubbling accele…

IMesMagnetizationchemistry.chemical_compoundZero field NMRMaterials scienceSpectrometerchemistryYield (chemistry)EvaporationAnalytical chemistryHyperpolarization (physics)Spin isomers of hydrogen
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<i>Geminal</i> Parahydrogen-Induced Polarization: Accumulating Long-Lived Singlet Order on Methylene Proton Pairs

2020

Abstract. In the majority of hydrogenative PHIP (Parahydrogen Induced Polarization) experiments, the hydrogen molecule undergoes pairwise cis-addition to an unsaturated precursor to occupy vicinal positions on the product molecule. However, some ruthenium-based hydrogenation catalysts induce geminal hydrogenation, leading to a reaction product in which the twohydrogen atoms are transferred to the same carbon center, forming a methylene (CH2) group. The singlet order of parahydrogen is substantially retained over the geminal hydrogenation reaction, giving rise to a singlet-hyperpolarized CH2 group. Although the T1 relaxation times of the methylene protons are often short, the singlet order h…

inorganic chemicalsGeminalHydrogen010405 organic chemistrychemistry.chemical_element010402 general chemistrySpin isomers of hydrogenPhotochemistry01 natural sciencesChemical reaction0104 chemical sciencesChemical kineticschemistry.chemical_compoundchemistryMoleculeSinglet stateMethylene
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Towards large‐scale steady‐state enhanced nuclear magnetization with in situ detection

2021

Magnetic resonance in chemistry 59(12), 1208 - 1215 (2021). doi:10.1002/mrc.5161

540 Chemistry and allied sciencesMagnetic Resonance Spectroscopy530 PhysicsEvaporation010402 general chemistrySpin isomers of hydrogen01 natural sciences530Catalysischemistry.chemical_compoundMagnetizationGeneral Materials Scienceddc:530Hyperpolarization (physics)Steady stateSpectrometer010405 organic chemistryGeneral Chemistry530 PhysikMagnetic Resonance Imaging0104 chemical sciencesIMeschemistryChemical physics540 ChemieYield (chemistry)
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