Solid‐state NMR measurements coupled with density functional theory (DFT) calculations demonstrate how hydrogen positions can be refined in a crystalline system. The precision afforded by rotational‐echo double‐resonance (REDOR) NMR to interrogate13C–1H distances is exploited along with DFT determinations of the13C tensor of carbonates (CO32−). Nearby1H nuclei perturb the axial symmetry of the carbonate sites in the hydrated carbonate mineral, hydromagnesite [4 MgCO3⋅Mg(OH)2⋅4 H2O]. A match between the calculated structure and solid‐state NMR was found by testing multiple semi‐local and dispersion‐corrected DFT functionals and applying them to optimize atom positions, starting from X‐ray diffraction (XRD)‐determined atomic coordinates. This was validated by comparing calculated to experimental13C{1H} REDOR and13C chemical shift anisotropy (CSA) tensor values. The results show that the combination of solid‐state NMR, XRD, and DFT can improve structure refinement for hydrated materials.
- Award ID(s):
- 1710671
- NSF-PAR ID:
- 10067384
- Date Published:
- Journal Name:
- Physical Chemistry Chemical Physics
- Volume:
- 20
- Issue:
- 13
- ISSN:
- 1463-9076
- Page Range / eLocation ID:
- 8475 to 8487
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Solid‐state NMR measurements coupled with density functional theory (DFT) calculations demonstrate how hydrogen positions can be refined in a crystalline system. The precision afforded by rotational‐echo double‐resonance (REDOR) NMR to interrogate13C–1H distances is exploited along with DFT determinations of the13C tensor of carbonates (CO32−). Nearby1H nuclei perturb the axial symmetry of the carbonate sites in the hydrated carbonate mineral, hydromagnesite [4 MgCO3⋅Mg(OH)2⋅4 H2O]. A match between the calculated structure and solid‐state NMR was found by testing multiple semi‐local and dispersion‐corrected DFT functionals and applying them to optimize atom positions, starting from X‐ray diffraction (XRD)‐determined atomic coordinates. This was validated by comparing calculated to experimental13C{1H} REDOR and13C chemical shift anisotropy (CSA) tensor values. The results show that the combination of solid‐state NMR, XRD, and DFT can improve structure refinement for hydrated materials.
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