Complexes of carbohydrates with metal cations. III. Conformations of alditols in aqueous solution

Abstract

Complex formation of alditols with metal ions in aqueous solution has been investigated by electrophoresis and by the study of the N.M.R. spectra in the presence of europium ions. Complexing occurs at three consecutive oxygen atoms which are in a gauche-gauche arrangement; the energy required to form this arrangement (by rotation around carbon-carbon bonds) determines the extent of complex formation. It appears that the alditols in aqueous solution are essentially in the same conformations as are their acetates in chloroform solution.