ROLE OF INTRAMOLECULAR HYDROGEN-BONDS IN THE INTERMOLECULAR HYDROGEN-BONDING OF CARBOHYDRATES

The cooperativity effects in hydrogen-bonded intermolecular interactio ns of carbohydrates are examined in this study. The nature of such eff ects is explored with ab initio quantum mechanical and density functio nal methods. Calculations are performed for complexes of 1,3-propanedi ol and n-propanol, which are used as model compounds to analyze hydrog en bond cooperativity in the dimerization of the sugar 1,3-diaxial dio l ydro-3-deoxy-3-N-methylamine-beta-D-glucopyranose. In addition to th e influence of cooperativity in the binding energy, the magnitude of c ooperativity effects is also examined from the change in key propertie s related to the formation of hydrogen bonds between monomers, which i nclude bond lengths, atomic partial charges, electron density at bond critical points, and stretching frequencies. The results reported hew provide a basis to discuss the relevance of cooperativity in molecular recognition of carbohydrates.