Abstract: Signal Amplification By Reversible Exchange (SABRE) is gaining increased attention as a tool to enhance weak Nuclear Magnetic Resonance (NMR) signals. In SABRE, spin order is transferred from parahydrogen (H2 in its nuclear singlet spin state) to a substrate molecule in a transient Ir-based complex. In recent years, SABRE polarization of biologically active substrates has been demonstrated, notably of metronidazole – an antibiotic and antiprotozoal drug. In this work, we study 15N SABRE polarization of metronidazole at natural isotope abundance. We are able to demonstrate significant 15N polarization reaching 15 %, which corresponds to a signal enhancement of 46,000 at 9.4 T for the nitrogen atom with lone electron pair. Additionally, the other two N-atoms can be polarized, although less efficiently. We present a detailed study of the field dependence of polarization and explain the maxima in the field dependence using the concept of coherent polarization transfer at level anti-crossings in the SABRE complex. A study of spin relaxation phenomena presented here enables optimization of the magnetic field for efficient storage of non-thermal polarization.

Cite: Kiryutin A.S. , Yurkovskaya A.V. , Ivanov K.L.
15N SABRE Hyperpolarization of Metronidazole at Natural Isotope Abundance
ChemPhysChem. 2021. V.22. N14. P.1470-1477. DOI: 10.1002/cphc.202100315 OpenAlex

Dates:

Submitted:	Apr 23, 2021
Accepted:	May 19, 2021
Published online:	Jun 11, 2021

Identifiers:

OpenAlex:

W3163716403

Citing:

DB	Citing
OpenAlex	20

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