Singlet NMR in a case of high molecular symmetry
Singlet NMR in a case of high molecular symmetry
Spin-1/2 pairs support nuclear singlet and triplet states. The mean population difference between the singlet and triplet manifolds is termed singlet order. Under suitable circumstances, nuclear singlet order is highly resistant to several relaxation mechanisms, displaying a decay time constant TS, which may greatly exceed the time constant T1 for the equilibration of nuclear magnetization. We explore the nuclear singlet relaxation of an isotopolog of squarate in a high-pH aqueous solution. The 1,3–13C2-isotopolog of squarate exists as a minority species of 1–13C2-squarate. This isotopolog has a high degree of molecular symmetry. 18O-enrichment is used to generate secondary isotope shifts of the 13C resonances, providing access to 13C2 double-quantum coherence and 13C2 singlet order. The 13C signals from the 1,2–13C2 and 1,3–13C2 species are selected using geometric double-quantum filtration, and the double-quantum coherence is converted to singlet order and back again using customized double-quantum-to-singlet (DQ2S) and singlet-to-double-quantum (S2DQ) pulse sequences. We report 13C2 singlet lifetime measurements for 1,3–13C2-squarate in a high-pH aqueous solution, in a high magnetic field.
Heramun, Urvashi D.
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Sabba, Mohamed
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Bengs, Christian
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Moustafa, Gamal A.I.
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Levitt, Malcolm H.
bcc5a80a-e5c5-4e0e-9a9a-249d036747c3
15 August 2025
Heramun, Urvashi D.
d528559c-9eb2-4b84-aa03-6b61fedfdaba
Sabba, Mohamed
bef5e5e8-18b2-43d9-8969-4a9b25bb8691
Bengs, Christian
cd3282d0-27ad-444f-bcb4-70eeab0029b9
Moustafa, Gamal A.I.
1a452cdc-4856-4243-9864-b391fb115f07
Levitt, Malcolm H.
bcc5a80a-e5c5-4e0e-9a9a-249d036747c3
Heramun, Urvashi D., Sabba, Mohamed, Bengs, Christian, Moustafa, Gamal A.I. and Levitt, Malcolm H.
(2025)
Singlet NMR in a case of high molecular symmetry.
The Journal of Chemical Physics, 163 (7), [074201].
(doi:10.1063/5.0286843).
Abstract
Spin-1/2 pairs support nuclear singlet and triplet states. The mean population difference between the singlet and triplet manifolds is termed singlet order. Under suitable circumstances, nuclear singlet order is highly resistant to several relaxation mechanisms, displaying a decay time constant TS, which may greatly exceed the time constant T1 for the equilibration of nuclear magnetization. We explore the nuclear singlet relaxation of an isotopolog of squarate in a high-pH aqueous solution. The 1,3–13C2-isotopolog of squarate exists as a minority species of 1–13C2-squarate. This isotopolog has a high degree of molecular symmetry. 18O-enrichment is used to generate secondary isotope shifts of the 13C resonances, providing access to 13C2 double-quantum coherence and 13C2 singlet order. The 13C signals from the 1,2–13C2 and 1,3–13C2 species are selected using geometric double-quantum filtration, and the double-quantum coherence is converted to singlet order and back again using customized double-quantum-to-singlet (DQ2S) and singlet-to-double-quantum (S2DQ) pulse sequences. We report 13C2 singlet lifetime measurements for 1,3–13C2-squarate in a high-pH aqueous solution, in a high magnetic field.
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Singlet NMR in a case of high molecular symmetry
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074201_1_5.0286843
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Accepted/In Press date: 24 July 2025
Published date: 15 August 2025
Identifiers
Local EPrints ID: 505196
URI: http://eprints.soton.ac.uk/id/eprint/505196
ISSN: 0021-9606
PURE UUID: 3a1ce24e-f35d-4815-ae71-fadf8791b792
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Date deposited: 01 Oct 2025 16:47
Last modified: 02 Oct 2025 02:07
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Author:
Urvashi D. Heramun
Author:
Mohamed Sabba
Author:
Christian Bengs
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