E. Zoidis et al., VIBRATIONAL SPECTROSCOPIC STUDIES ON THE STATE OF AGGREGATION OF WATER IN CARBON-TETRACHLORIDE, IN DIOXANE AND IN THE MIXED-SOLVENTS, Journal of molecular liquids, 64(1-2), 1995, pp. 197-210
A detailed infrared study of the vibrational modes of water in dioxane
, carbon tetrachloride and a mixed solvent as a function of concentrat
ion is reported. H2O/D2O mixtures have been used in order to isolate t
he uncoupled v(OH) and v(OD) modes. The data have been interpreted in
terms of the state of aggregation of water molecules in a hydrophobic
solvent and in a solvent to which hydrogen bonding can occur. It is sh
own that at very low concentrations (x(H2O) = 5x10(4)) water exists in
the monomeric form and can rotate rather freely. However, water is st
rongly self aggregated in a hydrophobic organic solvent for concentrat
ions greater than x(H2O) = 5x10(-3) (ie if there are more than 5 water
molecules in a 1000 solvent molecule 'bath'). Evidence of distinct (d
ioxane)(m)(water)(n) complexes is found in dioxane solution and in the
mixed solvent. However, as the water concentration is increased it is
clear that a water/solvent 'network' is formed. The aggregation proce
sses involving water depend critically, however, on the hydrophobicity
of the solvent mixture.