Long-lived states to sustain SABRE hyperpolarised magnetisation

Abstract

More than 4% net 1H-polarisation is created, in seconds, that is detectable for over 2 minutes.

Dynamic Nuclear Polarization of Long-Lived Nuclear Spin States in Methyl Groups

“…The hyperpolarized methyl long-lived states give rise to enhanced antiphase 13 C NMR signals in solution, which often persist for times much longer than the 13 C and 1 H spin-lattice relaxation times under the same conditions. The DNP-induced effects are similar to quantum-rotor-induced-polarization (QRIP), but are observed in a wider range of compounds, since they do not depend critically on the height of the rotational barrier.…”

“…Methyl LLS are implicated in the phenomenon of quantum-rotor-induced polarization (QRIP), in which strong antiphase 13 C signals are observed when certain compounds are cooled to cryogenic temperatures, rapidly dissolved in a hot solvent, and observed by solution NMR at room temperature. [19][20] QRIP has been observed for compounds such as γ-picoline (4-methylpyridine) for which the methyl rotation encounters an unusually low rotational barrier, leading to a significant tunnelling splitting of ~ 6 K between the A and E manifolds in the cryogenic solid state.…”

“…We have induced hyperpolarized long-lived states in compounds containing 13 C-bearing methyl groups by dynamic nuclear polarization (DNP) at cryogenic temperatures, followed by dissolution with a warm solvent. The hyperpolarized methyl long-lived states give rise to enhanced antiphase 13 C NMR signals in solution, which often persist for times much longer than the 13 C and 1 H spin-lattice relaxation times under the same conditions.…”

“…[7][8][9] LLS have been used as a carrier of hyperpolarisation. [10][11][12][13][14][15] Molecular scaffolds have been designed to minimise the relaxation rates of singlet order, with reported lifetimes of over an hour. 16 Such record lifetimes, however, concern chemical motifs that are not commonly found.…”

A Hyperpolarizable 1H Magnetic Resonance Probe for Signal Detection 15 Minutes after Spin Polarization Storage

“…demonstrated that long‐lived 15 N magnetization can be created and integrated into the chemically benign SABRE approach 25. A parallel approach of using SABRE to prepare hyperpolarized LLS in weakly coupled 1 H spin pairs have also been reported but the magnetization lasted under 90 s 26, 27…”