Optimisation of Pyruvate Hyperpolarisation using SABRE by Tuning the Active Magnetisation Transfer Catalyst

TY - JOUR

T1 - Optimisation of Pyruvate Hyperpolarisation using SABRE by Tuning the Active Magnetisation Transfer Catalyst

AU - Tickner, Benjamin

AU - IALI, Wissam

AU - Semenova, Olga

AU - Rayner, Peter John

AU - Whitwood, Adrian C.

AU - Duckett, Simon B.

N1 - © The Royal Society of Chemistry 2019.

PY - 2020/1/28

Y1 - 2020/1/28

N2 - Hyperpolarisation techniques such as Signal Amplification By Reversible Exchange (SABRE) can deliver NMR signals several orders of magnitude larger than those derived under Boltzmann conditions. SABRE is able to catalytically transfer latent magnetisation from para-hydrogen to a substrate in reversible exchange via temporary associations with an iridium complex. It has recently been applied to the hyperpolarisation of pyruvate, a substrate often used in many in vivo MRI studies. In this work, we seek to optimise the pyruvate-13C2 signal gains delivered through SABRE by fine tuning the properties of the active polarisation transfer catalyst. We present a detailed study of the effects of varying the carbene and sulfoxide ligands on the formation and behaviour of the active [Ir(H)2(η2-pyruvate)(sulfoxide)(NHC)] catalyst to produce a rational for achieving high pyruvate signal gains in a cheap and refreshable manner. This optimisation approach allows us to achieve signal enhancements of 2140 and 2125-fold for the 1-13C and 2-13C sites respectively of sodium pyruvate-1,2-[13C2].

AB - Hyperpolarisation techniques such as Signal Amplification By Reversible Exchange (SABRE) can deliver NMR signals several orders of magnitude larger than those derived under Boltzmann conditions. SABRE is able to catalytically transfer latent magnetisation from para-hydrogen to a substrate in reversible exchange via temporary associations with an iridium complex. It has recently been applied to the hyperpolarisation of pyruvate, a substrate often used in many in vivo MRI studies. In this work, we seek to optimise the pyruvate-13C2 signal gains delivered through SABRE by fine tuning the properties of the active polarisation transfer catalyst. We present a detailed study of the effects of varying the carbene and sulfoxide ligands on the formation and behaviour of the active [Ir(H)2(η2-pyruvate)(sulfoxide)(NHC)] catalyst to produce a rational for achieving high pyruvate signal gains in a cheap and refreshable manner. This optimisation approach allows us to achieve signal enhancements of 2140 and 2125-fold for the 1-13C and 2-13C sites respectively of sodium pyruvate-1,2-[13C2].

U2 - 10.1039/c9cy02498k

DO - 10.1039/c9cy02498k

M3 - Article

SN - 2044-4753

JO - Catalysis Science and Technology

JF - Catalysis Science and Technology

M1 - C9CY02498K

ER -