An 17O nuclear quadrupole resonance study of some carboxylic acids

Abstract

Using the new technique of doule resonance with coupled multiplets the nuclear quadrupole resonance spectra of 17O, naturally abundant at both the CO and COH sites in formic acid acrylic acid, fumaric acid, α-oxalic acid, β oxalic acid, maleic acid, acetic acid, and substituted acetic acids, were measured. The specimens were frozen solutions or powdered solids. For the COH site fine structure is observed on the spectral lines attributable to magnetic interaction with the neighboring proton. Analysis of the structure gives the sign of the quadrupole coupling constant and also information about the principal axes of the electric field gradient at the 17O nucleus. A simple Townes and Dailey analysis is carried out for the COH site.