Enhanced Hydrogen Bonding to Water Can Explain the Outstanding Solubility of \b{eta}-D-Glucose in Water

Abstract

Ab initio molecular dynamics (AIMD) simulations have been performed on aqueous solutions of four simple sugars, {\alpha}-D-glucose, \b{eta}-D-glucose, {\alpha}-D-mannose and {\alpha}-D-galactose. Hydrogen bonding (HB) properties, such as the number of donor and acceptor type HB-s, and the lengths and strengths of hydrogen bonds between sugar and water molecules, have been determined. Related electronic properties, such as the dipole moments of water molecules and partial charges of the sugar O-atoms, have also been calculated. The hydrophilic and hydrophobic shells were characterized by means of spatial distribution functions. \b{eta}-D-glucose has been found to form the highest number of hydrophilic and the smallest number of hydrophobic connections to neighboring water molecules. The average sugar-water H-bond length was the shortest for \b{eta}-D-glucose, which suggests that these are the strongest such H-bonds. Furthermore, \b{eta}-D-glucose appears to stand out in terms of symmetry properties of both its hydrophilic and hydrophobic hydration shells. In summary, in all aspects considered here, there seems to be a correlation between the distinct characteristics of \b{eta}-D-glucose and its outstanding solubility in water.