Ed Navarre - Complexation of phosphine ligands with peracetylated β-cyclodextrin in supercritical carbon dioxide: Spectroscopic determination of equilibrium constants.

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      Publication Details (including relevant citation   information):

      Galia, A., Navarre, E., Scialdone, O., Ferreira, M., Filardo, G.,   Tilloy, S. & Monflier, E. Journal of Physical Chemistry B.   111(10), 2573-2578, 2007.


      The interaction between peracetylated β-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.

      Address (URL): http://pubs.acs.org/doi/abs/10.1021/jp0673112