Direct and indirect hyperpolarisation of amines using parahydrogen
Wissam Iali1, Peter J Rayner1, Adel Alshehri1
1Centre for Hyperpolarisation in Magnetic Resonance (CHyM) , Department of Chemistry , University of York , Heslington , YO10 5DD , UK .
Chemical Science
|May 22, 2018
Summary
Hyperpolarisation methods like Signal Amplification By Reversible Exchange (SABRE) enhance Nuclear Magnetic Resonance (NMR) signals. This study details hyperpolarising amine nuclei (¹H, ¹³C, ¹⁵N) using para-hydrogen, achieving a 1000-fold signal gain.
Area of Science:
- Chemistry
- Physics
- Biomedical Engineering
Background:
- Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) are crucial for molecular and material studies.
- Hyperpolarisation techniques significantly amplify weak magnetic resonance signals.
Purpose of the Study:
- To detail the hyperpolarisation of amine nuclei (¹H, ¹³C, ¹⁵N) using para-hydrogen.
- To explore methods for enhancing signal strength in NMR and MRI of amines.
Main Methods:
- Utilising Signal Amplification By Reversible Exchange (SABRE) with iridium complexes.
- Optimising temperature and para-hydrogen pressure for hyperpolarisation.
- Employing SABRE-RELAY for amines with poor iridium binding.
Main Results:
- Achieved a 1000-fold NH signal gain for deuterated benzylamine at 9.4 T.
- Demonstrated successful hyperpolarisation of primary amines via labile iridium complexes.
- Showcased methods to hyperpolarise sterically hindered and electron-poor amines.
Conclusions:
- Developed effective chemical strategies for hyperpolarising a range of amines.
- Extended the applicability of para-hydrogen hyperpolarisation to diverse amine classes.
- These refinements hold significant potential for advancing NMR and MRI applications.
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