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Long‐Lived 1 H Nuclear Spin Singlet in Dimethyl Maleate Revealed by Addition of Thiols
Author(s) -
Zhang Yuning,
Soon Pei Che,
Jerschow Alexej,
Canary James W.
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201310284
Subject(s) - hyperpolarization (physics) , chemistry , singlet oxygen , singlet state , nuclear magnetic resonance spectroscopy , molecule , photochemistry , nuclear magnetic resonance , excited state , stereochemistry , atomic physics , organic chemistry , physics , oxygen
Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) have become important techniques in many research areas. One major limitation is the relatively low sensitivity of these methods, which recently has been addressed by hyperpolarization. However, once hyperpolarization is imparted on a molecule, the magnetization typically decays within relatively short times. Singlet states are well isolated from the environment, such that they acquire long lifetimes. We describe herein a model reaction for read‐out of a hyperpolarized long‐lived state in dimethyl maleate using thiol conjugate addition. This type of reaction could lend itself to monitoring oxidative stress or hypoxia by sensitive detection of thiols. Similar reactions could be used in biosensors or assays that exploit molecular switching. Singlet lifetimes of about 4.7 min for 1 H spins in [D 4 ]MeOH are seen in this system.