The conformations of tartaric acids in aqueous solution studied by 1H and 13C nuclear magnetic resonance

Abstract

Vicinal H—H and C—H coupling constants are reported for (+)-tartaric acid and meso-tartaric acid at various pH values and used in a discussion of the conformation of these molecules. This is found not to change much with pH. For the meso form, in particular, the most favoured conformer is determined not so much by the possibility of internai [Formula: see text] hydrogen bonding but, at least in part, by stabilization of polar conformations in a sol vent (H2O) of high dielectric constant.