Heterogeneous Microtesla SABRE Enhancement of 15N NMR Signals

• DOI: 10.1002/ange.201705014
• Publication Date: 2017-06-23T22:09:40Z
• Authors: Kirill V. Kovtunov; Larisa M. Kovtunova; Max E. Gemeinhardt; Andrey V. Bukhtiy...; Jonathan Gesiorski; Valerii I. Bukhti...; Eduard Y. Chekmenev; Igor V. Koptyug; Boyd M. Goodson
• Keywords: Magnetic Resonance Spectroscopy; Nitrogen Isotopes; Organometallic Compounds; 01 natural sciences; Catalysis; Hydrogen; 0104 chemical sciences

AbstractThe hyperpolarization of heteronuclei via signal amplification by reversible exchange (SABRE) was investigated under conditions of heterogeneous catalysis and microtesla magnetic fields. Immobilization of [IrCl(COD)(IMes)], [IMes=1,3‐bis(2,4,6‐trimethylphenyl), imidazole‐2‐ylidene; COD=cyclooctadiene] catalyst onto silica particles modified with amine linkers engenders an effective heterogeneous SABRE (HET‐SABRE) catalyst that was used to demonstrate a circa 100‐fold enhancement of 15N NMR signals in 15N‐pyridine at 9.4 T following parahydrogen bubbling within a magnetic shield. No 15N NMR enhancement was observed from the supernatant liquid following catalyst separation, which along with XPS characterization supports the fact that the effects result from SABRE under heterogeneous catalytic conditions. The technique can be developed further for producing catalyst‐free agents via SABRE with hyperpolarized heteronuclear spins, and thus is promising for biomedical NMR and MRI applications.