Thermodynamic (volume and compressibility) and spectral investigations of the glycine, diglycine and triglycine in aqueous α- and β-cyclodextrin solutions at T=298.15 K

Apparent molar volumes and apparent molar adiabatic compressibilities have been determined for glycine, diglycine, and triglycine in aqueous alpha- and beta-cyclodextrin (0.002-0.008 mol kg(-1)) solutions by measurements of densities and speeds of sound at 298.15 K. The limiting apparent molar volume, limiting apparent molar adiabatic compressibilities, and their corresponding slopes were computed using the density and speed of sound data. These data were used to calculate the transfer values of partial molar volumes and partial molar adiabatic compressibilities at infinite dilution. Transfer parameters have been interpreted from the point of view of concentration dependence of solute-solute and solute-solvent interactions. These transfer parameters have further been used to calculate the group contribution of a peptide backbone (-CH2CONH-)(n) unit. The experimental results have also been discussed on the basis of H-1 NMR measurements. (C) 2012 Elsevier B.V. All rights reserved.