Long‐Term Generation of Longitudinal Spin Order Controlled by Ammonia Ligation Enables Rapid SABRE Hyperpolarized 2D NMR
| Autor: | James G. Kempf, Eric Breynaert, Jean-Max Tyburn, Johan A. Martens, Francis Taulelle, Sophie De Ridder, Ewoud Vaneeckhaute |
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| Jazyk: | angličtina |
| Předmět: |
Materials science
Hydride chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Spin isomers of hydrogen 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Catalysis Magnetization chemistry.chemical_compound chemistry Pyridine Physical chemistry Singlet state Hyperpolarization (physics) Iridium Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Chemphyschem |
| ISSN: | 1439-7641 1439-4235 |
| DOI: | 10.1002/cphc.202100079 |
| Popis: | Symmetry breaking of parahydrogen using iridium catalysts converts singlet spin order into observable hyperpolarization. In this contribution, iridium catalysts are designed to exhibit asymmetry in their hydrides, regulated by in situ generation of deuterated ammonia governed by ammonium buffers. The concentrations of ammonia (N) and pyridine (P) provide a handle to generate a variety of stereo-chemically asymmetric N-heterocyclic carbene iridium complexes, ligating either [3xP], [2xP;N], [P;2xN] or [3xN] in an octahedral SABRE type configuration. The non-equivalent hydride positions, in correspondence with the ammonium buffer solutions, enables to extend singlet-triplet or | ⟩ → | ⟩ mixing at high magnetic field and experimentally induce prolonged generation of non-equilibrium longitudinal two-spin order. This long-lasting magnetization can be exploited in hyperpolarized 2D-OPSY-COSY experiments providing direct structural information on the catalyst using a single contact with parahydrogen. Separately, field cycling revealed hyperpolarization properties in low-field conditions. Controlling catalyst stereochemistry by introducing small and deuterated ligands, such as deuterated ammonia, simplifies the spin-system. This is shown to unify experimental and theoretically derived field-sweep experiments for four-spin systems. ispartof: Chemphyschem vol:22 issue:12 pages:1170-1177 ispartof: location:Germany status: Published online |
| Databáze: | OpenAIRE |
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