SABRE-Relay: A Versatile Route to Hyperpolarization

Autor: Roy, Soumya S., Appleby, Kate M., Fear, Elizabeth J., Duckett, Simon B.
Jazyk: angličtina
Zdroj: The Journal of Physical Chemistry Letters
ISSN: 1948-7185
DOI: 10.1021/acs.jpclett.7b03026
Popis: Signal Amplification by Reversible Exchange (SABRE) is used to switch on the latent singlet spin order of para-hydrogen (p-H2) so that it can hyperpolarize a substrate (sub = nicotinamide, nicotinate, niacin, pyrimidine and pyrazine). The substrate then reacts reversibly with [Pt(OTf)2(bis-diphenylphosphinopropane)] by displacing OTf- to form [Pt(OTf)(sub)(bis-diphenylphosphinopropane)]OTf. The 31P NMR signals of these metal complexes prove to be enhanced when the substrate possesses an accessible singlet state or long-lived Zeeman polarization. In the case of pyrazine, the corresponding 31P signal was 105 ± 8 times larger than expected, which equated to an 8-hour reduction in total scan time for an equivalent signal to noise ratio under normal acquisition conditions. Hence p-H2 derived spin order is successfully relayed into a second metal complex via a suitable polarization carrier (sub). When fully developed we expect this route involving a second catalyst to successfully hyperpolarize many classes of substrate that are not amenable to normal SABRE.
Databáze: OpenAIRE