M. Bastos et al., INTERACTIONS IN THE MODEL SYSTEM ALPHA-CYCLODEXTRIN-GLYCEROL - EXPERIMENTAL AND THEORETICAL-STUDY, Journal of the Chemical Society. Faraday transactions, 93(11), 1997, pp. 2061-2067
Citations number
40
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
The association between alpha-cyclodextrin and glycerol has been studi
ed using experimental and theoretical methods. The experimental techni
que used was microcalorimetric stepwise titration at 288.15, 298.15 an
d 313.15 K. The formation of a 1:1 complex between alpha-cyclodextrin
and glycerol, in aqueous solutions, is indicated. There was no tempera
ture dependence of the observed parameters. The thermodynamic paramete
rs were K = 1.34 +/- 0.07, Delta H degrees = (-3.1 +/- 0.1) kJ mol(-1)
, Delta G degrees = (-0.7 +/- 0.1) kJ mol(-1) and Delta S degrees = (-
8 +/- 4) J K-1 mol(-1) (Gibbs energy and entropy values calculated for
298.15 K). Molecular dynamics simulations have also been carried out.
The average structures, obtained from 100 ps of dynamics, are compare
d with the solvated 'empty' alpha-cyclodextrin average structure. The
dynamics calculations show that there is a structurally and energetica
lly favourable association between the molecules, which is in good agr
eement with the experimental findings.