Determination of the Rotational Correlation Time of Water by Proton NMR Relaxation in H₂¹⁷O and Some Related Results

Abstract

Analysis of the 1H‐17O dipolar contribution to the proton longitudinal relaxation rate in 17O‐enriched water yields a correlation time for re‐orientation of the O–H vector τrOH = (1.71 ± 0.07) ps in H2O at 25 °C. This result is insensitive to uncertainties in the calculated intermolecular relaxation contribution. From 1H, D, and 17O relaxation rates in H2O/D2O mixtures deuterium isotope effects on the correlation times were estimated. The quadrupole coupling constants of D and 17O in liquid water were determined.

A New Method for the Determination of the Dynamic Isotope Effect and the Deuterium Quadrupole Coupling Constant in Liquids

“…This is in contrast to the behavior of the deuterium QCC in water. Here the QCC ranges from 212 kHz in ice (32) over 255 kHz in the liquid at room temperature (33,34) to 315 kHz in gas (32). The QCC probes the electric field gradient (efg) at the site of the nucleus.…”

Oxygen-17 NMR spectroscopy: Basic principles and applications (part II)

“…Leyte and co-workers have re-analyzed T 1 data of 1 H, 2 H and 17 O nuclei in water together with new experimental data on the 1 HA 17 O dipole-dipole interaction, obtaining an isotropic correlation time s c = 1.7 ps at 25°C [763]; this value Table 150 Correlation times, s c , 17 O quadrupolar coupling constants, v, and anisotropies of the 13 C chemical shielding tensors, Dr, for the complexes Al(acac) 3 (acac:pentanedionate anion) and Zr(acac) 4 , and for pentane-2,4-dione (acetylacetone), Hacac (keto-enol, first line; diketone form, second line). Adapted, with permission, from Inorg.…”

The Anisotropy of the Molecular Reorientational Motions in Liquid Methanol

“…NMR relaxation time measurements on isotopi cally substituted samples are a sensitive way to probe the reorientational dynamics of single molecules [3,4]. Earlier studies of liquid methanol measuring deuteron relaxation rates depend on proper estimation of the deuterium quadrupole coupling constant for the eval uation of the reorientational correlation time [5][6][7][8].…”