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Updated: Jul 14, 2026
14:55
Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Indirect detection of nitrogen-14 in solid-state NMR spectroscopy
Simone Cavadini1, Sasa Antonijevic, Adonis Lupulescu
1Laboratoire de Résonance Magnétique Biomoléculaire, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, Batochime, 1015 Lausanne, Switzerland. simone.cavadini@epfl.ch
Summary
This study introduces a new NMR method for analyzing nitrogen-14 (spin I=1) in solid materials. The technique uses coherence transfer from a spy nucleus to reveal detailed structural and dynamic information about nitrogen-containing solids.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
- Quantum Coherence Transfer
- Quadrupolar Nuclei Analysis
Background:
- Nitrogen-14 (14N) NMR spectroscopy is challenging due to its spin I=1 and quadrupolar interactions.
- Indirect detection methods are crucial for overcoming sensitivity limitations in solid-state NMR.
- Understanding quadrupolar couplings is key to characterizing nitrogen-containing materials.
Purpose of the Study:
- To develop and validate an indirect detection NMR method for solid-state 14N spectroscopy.
- To investigate the influence of quadrupolar couplings and molecular orientation on 14N NMR spectra.
- To demonstrate the utility of this technique for structural and dynamic analysis of nitrogenous solids.
Main Methods:
- Indirect detection NMR using coherence transfer from a spin-1/2 'spy' nucleus (e.g., 13C, 1H) to 14N.
- Utilizing scalar couplings and residual dipolar splittings (RDS) for coherence transfer.
- Acquiring two-dimensional (2D) NMR spectra of magic-angle spinning powders.
Main Results:
- Observed 2D NMR spectra exhibit powder patterns governed by second- and third-order quadrupolar couplings.
- Spectra are sensitive to the quadrupolar coupling constant C(Q), asymmetry parameter eta(Q), and internuclear vector orientation.
- Motional averaging of these parameters provides insights into molecular dynamics.
Conclusions:
- The developed indirect detection NMR method effectively characterizes 14N nuclei in solids.
- The technique provides valuable structural and dynamic information about nitrogen-containing compounds.
- Applications to amino acids demonstrate the broad applicability and scope of the method.
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