Molecular hydration of carbohydrates: quantum chemical study of xylofuranose–(H2O)n clusters

Abstract

The structure, energetics and vibrational spectra of xylofuranose–(H2O)n where n = 2 to 10 cluster have been investigated by using Moller–Plesset second-order perturbation theory (MP) with aug-cc-pvdz as a basis set. Complete basis set limit for the xylofuranose–water clusters were calculate at MP2 level of theory. The incoming water molecule prefers the water–water interaction over the xylose–water interaction. The structural analysis shows that the average water–water distances are observed to be of similar. The calculated O–H stretching frequency is seen to blue shift in all except di-, penta- and hepta-hydrated clusters. In these clusters, the O–H frequency red shifts from isolated xylofuranose molecule. Because the OH group in these clusters is taking part either in intermolecular hydrogen bonding with water molecule or in intramolecular H-bonding with other OH groups present in xylose ring.