¹⁷O NMR Investigation of Water Structure and Dynamics

Abstract

The structure and dynamics of the bound water in barium chlorate monohydrate were studied with 17O nuclear magnetic resonance (NMR) spectroscopy in samples that are stationary and spinning at the magic-angle in magnetic fields ranging from 14.1 to 21.1 T. 17O NMR parameters of the water were determined, and the effects of torsional oscillations of the water molecule on the 17O quadrupolar coupling constant (CQ) were delineated with variable temperature MAS NMR. With decreasing temperature and reduction of the librational motion, we observe an increase in the experimentally measured CQ explaining the discrepancy between experiments and predictions from density functional theory. In addition, at low temperatures and in the absence of 1H decoupling, we observe a well-resolved 1H–17O dipole splitting in the spectra, which provides information on the structure of the H2O molecule. The splitting arises because of the homogeneous nature of the coupling between the two 1H–17O dipoles and the 1H–1H dipole.

17O MAS NMR Correlation Spectroscopy at High Magnetic Fields

“…We note that 1 H decoupling during acquisition of 17 O MAS NMR spectra did not affect the second-order line shape of the spectrum ( Figure S6). 54 The timing diagrams of the multidimensional pulse sequences involving 17 13 C, 15 N cross-polarization (CP), [70][71] and 1 H MAS NMR experiments were performed at 11.7 T (ω0H/2π = 500 MHz, homebuilt spectrometer courtesy of Dr. Dave Ruben, FBML-MIT) and 21.1 T, with ωR/2π =10 and 20 kHz, respectively. Two-dimensional 13 C-13 C (RFDR) 21 and 13 C-15 N (ZF-TEDOR) 72 experiments were performed at 11.7 T.…”

Probing nitrite ion dynamics in NaNO2 crystals by solid‐state 17O NMR

“…On the other hand, only two out six O − –Na + bonds are present in the transition state of the 2‐fold jump in solid NaNO 2 . We should point out that the situation of O − –Na + interactions in solid NaNO 3 is very similar to the O···H–N hydrogen bonding environment for the 3‐fold jump within a molecular cage . In this latter case, the E a value for 3‐fold jump is only 22 kJ mol −1 .…”

“…While solid‐state 17 O ( I = 5/2) NMR has become quite common in recent years, to the best of our knowledge, no solid‐state 17 O NMR study has been reported for NaNO 2 . Furthermore, there are few examples in the literature where solid‐state 17 O NMR is used to probe molecular motion in solid materials . In this study, our objective is to use solid‐state 17 O NMR to probe the ion dynamics in the low‐temperature ferroelectric phase of NaNO 2 .…”

Direct detection and characterization of bioinorganic peroxo moieties in a vanadium complex by 17O solid-state NMR and density functional theory

“…For example, ionic interactions of oxygen centers with metal ions have been shown to affect 17 O NMR parameters in biological systems [32, 33]; and large negative 17 O isotropic shifts have been reported for transition metal bound oxygen-containing ligands [34–37]. 17 O chemical shifts in crystalline amino acids have also been demonstrated to correlate linearly with bond distance and angles [38] and variable-temperature measurements have been used to examine the dynamics and measure 1 H- 17 O couplings allowing for the measurements of O-H bond distances in barium chlorate monohydrate [39]. DFT calculations on bioinorganic complexes can help to correlate the experimental NMR parameters with local coordination environment and geometry of the observed nuclei [40–43].…”