TY - JOUR

T1 - Efficient polarization redistribution in hyperpolarized 1-D-propane produced via pairwise parahydrogen addition

AU - Ariyasingha, Nuwandi M.

AU - Nantogma, Shiraz

AU - Samoilenko, Anna

AU - Salnikov, Oleg G.

AU - Chukanov, Nikita V.

AU - Kovtunova, Larisa M.

AU - Koptyug, Igor V.

AU - Chekmenev, Eduard Y.

N1 - We acknowledge funding from NIH NHLBI 5F32HL160108–01, DOD CDMRP W81XWH-20–10576, NSF CHE-1904780 and Wayne State University Thomas C. Rumble University Graduate Fellowship (SN). The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. O.G.S. thanks the Council on Grants of the President of the Russian Federation (grant MK-2826.2022.1.3). I.V.K. thanks the Ministry of Science and Higher Education of the Russian Federation for financial support of PHIP effect calculations. Публикация для корректировки.

PY - 2023/12

Y1 - 2023/12

N2 - Parahydrogen-Induced Polarization (PHIP) is NMR hyperpolarization technique that has matured from fundamental science to a biomedical tool for production of hyperpolarized MRI contrast agents. The spin order of nascent parahydrogen-derived protons can be employed directly for enhancement of their NMR signals or for polarization transfer to other nuclei in the hydrogenation product. In this work, we study the process of pairwise parahydrogen addition to propylene, which results in symmetric propane molecule with substantially enhanced methyl and methylene NMR signals. Specifically, we have synthesized site-selectively isotopically labeled 3-D-propylene molecule to study polarization dynamics in the resulting monodeuterated propane after pairwise parahydrogen addition. The deuterium presence in the hyperpolarized propane product results in a minute isotope chemical shift effect allowing to distinguish the proton resonances of CH3 and CH2D groups at 600 MHz. Pairwise parahydrogen 1,2-addition to 3-D-propylene was first confirmed by performing the reaction inside a 600 MHz NMR spectrometer, i.e., in the weakly-coupled regime at 14 T, where proton polarization dynamics is restricted to the molecular sites of parahydrogen addition. However, when the pairwise parahydrogen addition is performed in the strongly-coupled regime, i.e., at the Earth's magnetic field, efficient polarization transfer to CH2D protons is readily observed, leading to polarization redistribution between the three inequivalent sites. This finding is important as it sheds light on polarization dynamics in the strongly coupled symmetric spin systems such as propane studied here—the presented results are expected to be applicable to other spin systems such as butane.

AB - Parahydrogen-Induced Polarization (PHIP) is NMR hyperpolarization technique that has matured from fundamental science to a biomedical tool for production of hyperpolarized MRI contrast agents. The spin order of nascent parahydrogen-derived protons can be employed directly for enhancement of their NMR signals or for polarization transfer to other nuclei in the hydrogenation product. In this work, we study the process of pairwise parahydrogen addition to propylene, which results in symmetric propane molecule with substantially enhanced methyl and methylene NMR signals. Specifically, we have synthesized site-selectively isotopically labeled 3-D-propylene molecule to study polarization dynamics in the resulting monodeuterated propane after pairwise parahydrogen addition. The deuterium presence in the hyperpolarized propane product results in a minute isotope chemical shift effect allowing to distinguish the proton resonances of CH3 and CH2D groups at 600 MHz. Pairwise parahydrogen 1,2-addition to 3-D-propylene was first confirmed by performing the reaction inside a 600 MHz NMR spectrometer, i.e., in the weakly-coupled regime at 14 T, where proton polarization dynamics is restricted to the molecular sites of parahydrogen addition. However, when the pairwise parahydrogen addition is performed in the strongly-coupled regime, i.e., at the Earth's magnetic field, efficient polarization transfer to CH2D protons is readily observed, leading to polarization redistribution between the three inequivalent sites. This finding is important as it sheds light on polarization dynamics in the strongly coupled symmetric spin systems such as propane studied here—the presented results are expected to be applicable to other spin systems such as butane.

KW - Hyperpolarization

KW - NMR

KW - Parahydrogen

KW - Propane

KW - Spectroscopy

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85174747384&origin=inward&txGid=87ccb82cacdf4507be56c3f5291ca0e4

UR - https://www.mendeley.com/catalogue/7e2aab7c-3af9-37b5-8826-7b7bf69c27de/

U2 - 10.1016/j.jmro.2023.100135

DO - 10.1016/j.jmro.2023.100135

M3 - Article

VL - 16-17

JO - Journal of Magnetic Resonance Open

JF - Journal of Magnetic Resonance Open

SN - 2666-4410

M1 - 100135

ER -