Deuterium isotope effects on 17O nuclear shielding in a single water molecule from NMR gas phase measurements

Abstract

Small amounts of enriched H₂¹⁷O and ³He in gaseous mixtures with CH₃F and CF₃H were studied using ¹H, ³He and ¹⁷O NMR spectroscopy. After extrapolation of the results to the zero density limit, the shielding constants in the isolated molecules: H₂¹⁷O, H¹⁷OD and D₂¹⁷O were precisely determined. The isotope effects are as follows: ²Δ¹H(HOH, HOD) = −0.040 ppm, ¹Δ¹⁷O(H₂O, HOD) = −1.51 ppm and ¹Δ¹⁷O(HOD, D₂O) = −1.48 ppm.