Investigation of hydrogen‐bonded compounds using high‐resolution NMR spectroscopy in solids. Part 3—¹H chemical shifts in polycrystalline trihydrogen selenites

Proton Distributions and Hydrogen Bonding in Crystalline and Glassy Hydrous Silicates and Related Inorganic Materials: Insights from High‐Resolution Solid‐State Nuclear Magnetic Resonance Spectroscopy

“…A least‐squares linear fit to the data for R(O⋯O) ≤2.8 Å yielded a correlation δ i H (ppm)=90.31–30.40R(O⋯O) (Å) with the coefficient of determination R 2 =0.98. This new correlation in general agrees with the 1 H NMR data for silicates and selenites reported previously 9,12,44 …”

“…Based on 1 H MAS NMR and CRAMPS data available on phosphates and other compounds (including carboxylic acids), Yesinowski et al 32 derived a linear correlation δ i H =79.05–25.5R(O⋯O) (Å) for the entire R(O⋯O) range up to about 3.1 Å, although it was noted that the correlation for R(O⋯O) >2.9 Å should be viewed with caution because of poor data coverage. 1 H CRAMPS data reported subsequently for a number of silicates 9 and selenites 44 yield systematically lower δ i H values than predicted by this correlation. Experimental 1 H NMR data on crystalline phases containing MgOH and CaOH groups and ab initio cluster calculations have shown that the slope for the δ i H vs. R(O⋯O) correlation levels off at long R(O⋯O), suggesting that it is unreasonable to fit a single, linear correlation for the entire R(O⋯O) range 14 .…”

“…In these experiments, the multiple pulses eliminate the homonuclear dipolar interactions, and slow MAS removes the residual anisotropies resulting from chemical shift anisotropy and heteronuclear dipolar interactions. These methods have been applied to various inorganic materials, including (oxy)hydroxides, 42 silicates, 9,43 selenites, 44 and phosphates 45 . For CRAMPS experiments, the chemical shift scale must be corrected, because the multiple pulse sequence not only averages out the homonuclear dipolar interaction but also scales down the chemical shift interaction.…”

2H chemical shift anisotropies from high-field 2H MAS NMR spectroscopy

“…exhibit linear correlations with the 2 H quadrupole coupling constants determined for the corresponding O-DÁ Á ÁO sites. Linear correlations between d iso ( 1 H) and the r OÁÁÁO bond length have also been reported for carboxylic acids [26], trihydrogen selenites [27], and for metal phosphates and other minerals [28]. Furthermore, correlations between d iso ( 1 H) as well as C Q ð 2 HÞ and the inverse of the hydrogen bond distance (r À1 HÁÁÁO ) have been observed for a number of 1 H/ 2 H sites in hydrogen bonds [29].…”

1 H CSA parameters by ultrafast MAS NMR: Measurement and applications to structure refinement

“…Subsequently, a linear correlation between the isotropic 1 H shift δiso( 1 H) and d(H…O) was established by comparison with neutron diffraction data [10]. Many similar relationships have been found for phosphates [11], hydrosilicates [12], selenites [13] and amino acids [14], and these are commonly used to extract hydrogen bond lengths from solid-state NMR measurements. However, later studies suggest that the situation is more complicated than first thought.…”