TY - JOUR

T1 - Hyperpolarization of cis-15N2-Azobenzene by Parahydrogen at Ultralow Magnetic Fields

AU - Sheberstov, Kirill F.

AU - Kozinenko, Vitaly P.

AU - Kiryutin, Alexey S.

AU - Vieth, Hans Martin

AU - Zimmermann, Herbert

AU - Ivanov, Konstantin L.

AU - Yurkovskaya, Alexandra V.

N1 - Funding Information: K.F.S. is grateful to James Eills and Danila Barskiy for useful discussions and help with editing of the manuscript. We acknowledge the Russian Science Foundation for the grant #20‐63‐46034. K.F.S. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement No 766402. Open access funding enabled and organized by Projekt DEAL. Publisher Copyright: © 2021 The Authors. ChemPhysChem published by Wiley-VCH GmbH Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/7/16

Y1 - 2021/7/16

N2 - The development of nuclear spins hyperpolarization, and the search for molecules that can be efficiently hyperpolarized is an active area in nuclear magnetic resonance. In this work we present a detailed study of SABRE SHEATH (signal amplification by reversible exchange in shield enabled alignment transfer to heteronuclei) experiments on 15N2-azobenzene. In SABRE SHEATH experiments the nuclear spins of the target are hyperpolarized through transfer of spin polarization from parahydrogen at ultralow fields during a reversible chemical process. Azobenzene exists in two isomers, trans and cis. We show that all nuclear spins in cis-azobenzene can be efficiently hyperpolarized by SABRE at suitable magnetic fields. Enhancement factors (relative to 9.4 T) reach up to 3000 for 15N spins and up to 30 for the 1H spins. We compare two approaches to observe either hyperpolarized magnetization of 15N/1H spins, or hyperpolarized singlet order of the 15N spin pair. The results presented here will be useful for further experiments in which hyperpolarized cis-15N2-azobenzene is switched by light to trans-15N2-azobenzene for storing the produced hyperpolarization in the long-lived spin state of the 15N pair of trans-15N2-azobenzene.

AB - The development of nuclear spins hyperpolarization, and the search for molecules that can be efficiently hyperpolarized is an active area in nuclear magnetic resonance. In this work we present a detailed study of SABRE SHEATH (signal amplification by reversible exchange in shield enabled alignment transfer to heteronuclei) experiments on 15N2-azobenzene. In SABRE SHEATH experiments the nuclear spins of the target are hyperpolarized through transfer of spin polarization from parahydrogen at ultralow fields during a reversible chemical process. Azobenzene exists in two isomers, trans and cis. We show that all nuclear spins in cis-azobenzene can be efficiently hyperpolarized by SABRE at suitable magnetic fields. Enhancement factors (relative to 9.4 T) reach up to 3000 for 15N spins and up to 30 for the 1H spins. We compare two approaches to observe either hyperpolarized magnetization of 15N/1H spins, or hyperpolarized singlet order of the 15N spin pair. The results presented here will be useful for further experiments in which hyperpolarized cis-15N2-azobenzene is switched by light to trans-15N2-azobenzene for storing the produced hyperpolarization in the long-lived spin state of the 15N pair of trans-15N2-azobenzene.

KW - azobenzene

KW - NMR

KW - Parahydrogen

KW - SABRE

KW - ZULF

UR - http://www.scopus.com/inward/record.url?scp=85107813002&partnerID=8YFLogxK

U2 - 10.1002/cphc.202100160

DO - 10.1002/cphc.202100160

M3 - Article

C2 - 33932314

AN - SCOPUS:85107813002

VL - 22

SP - 1527

EP - 1534

JO - ChemPhysChem

JF - ChemPhysChem

SN - 1439-4235

IS - 14

ER -