Zero-field J-spectroscopy of quadrupolar nuclei.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38802356.
- Also identified by DOI 10.1038/s41467-024-48390-2 and PMC identifier 11637023.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Zero- to ultralow-field nuclear magnetic resonance (ZULF NMR) allows molecular structure elucidation via measurement of electron-mediated spin-spin J-couplings. This study examines zero-field J-spectra from molecules with quadrupolar nuclei, exemplified by solutions of various isotopologues of ammonium cations. The spectra reveal differences between various isotopologues upon extracting precise J-coupling values from pulse-acquire measurements. A primary isotope effect, <math xmlns="http://www.w3.org/1998/Math/MathML"><mo>△</mo> <mi>J</mi> <mo>=</mo> <mfenced> <mrow> <msub><mrow><mi>γ</mi></mrow> <mrow><msup><mrow></mrow> <mrow><mn>14</mn></mrow> </msup> <mi>N</mi></mrow> </msub> <mo>/</mo> <msub><mrow><mi>γ</mi></mrow> <mrow><msup><mrow></mrow> <mrow><mn>15</mn></mrow> </msup> <mi>N</mi></mrow> </msub> </mrow> </mfenced> <msub><mrow><mi>J</mi></mrow> <mrow><msup><mrow></mrow> <mrow><mn>15</mn></mrow> </msup> <mi>N</mi> <mi>H</mi></mrow> </msub> <mo>-</mo> <msub><mrow><mi>J</mi></mrow> <mrow><msup><mrow></mrow> <mrow><mn>14</mn></mrow> </msup> <mi>N</mi> <mi>H</mi></mrow> </msub> <mo>≈</mo> <mo>-</mo> <mn>58</mn></math> mHz, is deduced by analysis of the proton-nitrogen J-coupling ratios. This study points toward further experiments with symmetric cations containing quadrupolar nuclei, promising applications in biomedicine, energy storage, and benchmarking quantum chemistry calculations.