The interaction between peracetylated beta-cyclodextrin and several triphenyl phosphine derivatives was studied in supercritical carbon dioxide (scCO2) by UV-visible spectroscopy. The equilibrium constant for a 1:1 complexation reaction was obtained from titration spectra and calculated using two established mathematical models. The values of the equilibrium constants are 1-3 orders of magnitude smaller than those obtained in aqueous solution with analogous phosphines. This is likely due to the absence in scCO2 of the hydrophobic effect, which is replaced by a corresponding, but weaker, CO2-phobic effect. The largest value of Kf was found for complexes of diphenyl(4-adamantylphenyl)phosphine, which is rationalized on the basis of the excellent fit of the phosphine in the cyclodextrin cavity, leading to enhanced host-guest van der Waals interactions. This study can be considered the first step toward the comprehension of the complexation thermodynamics of modified cyclodextrins soluble in scCO2.
|Data di pubblicazione:||2007|
|Titolo:||Complexation of phosphine ligands with peracetylated β-cyclodextrin in supercritical carbon dioxide: spectroscopic determination of equilibrium constants|
|Autori:||GALIA, A; NAVARRE, EC; SCIALDONE, O; MICHEL FERREIRA; FILARDO, G; SEBASTIEN TILLOY; ERIC MONFLIER|
|Tipologia:||Articolo su rivista|
|Citazione:||GALIA, A., NAVARRE, E.C., SCIALDONE, O., MICHEL FERREIRA, FILARDO, G., SEBASTIEN TILLOY, et al. (2007). Complexation of phosphine ligands with peracetylated β-cyclodextrin in supercritical carbon dioxide: spectroscopic determination of equilibrium constants. JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL, 111, 2573-2578.|
|Digital Object Identifier (DOI):||10.1021/jp0673112|
|Appare nelle tipologie:||01 - Articolo su rivista|