Abstract
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 inaqueous 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 wasfound for complexes of diphenyl(4-adamantylphenyl)phosphine, which is rationalized on the basis of theexcellent 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 complexationthermodynamics of modified cyclodextrins soluble in scCO2.
Lingua originale | English |
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pagine (da-a) | 2573-2578 |
Rivista | JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL |
Volume | 111 |
Stato di pubblicazione | Published - 2007 |
All Science Journal Classification (ASJC) codes
- ???subjectarea.asjc.1600.1606???
- ???subjectarea.asjc.2500.2508???
- ???subjectarea.asjc.2500.2505???