Complexation of phosphine ligands with peracetylated β-cyclodextrin insupercritical carbon dioxide: Effect of temperature and cosolvent on theequilibrium constant

Onofrio Scialdone, Alessandro Galia, Giuseppe Filardo, Eric Monflier, Edward Charles Navarre

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Abstract

The interaction between peracetylated -β-cyclodextrin and tert-butyl and adamantyl functionalized triphenylphosphine derivatives was studied in supercritical carbon dioxide (scCO2) based solvent mediaby UV–vis spectroscopy. The equilibrium constant for a 1:1 complexation reaction was obtained from titration spectra both in pure carbon dioxide and in the presence of methanol as a cosolvent in the temperaturerange 308–323K to estimate the internal energy and entropy of the inclusion equilibrium. The values of the equilibrium constants were found significantly smaller than those obtained in aqueous solution with analogous phosphines and substantially independent of the nature of the phosphine and of the solvent medium. On the basis of the results that we have obtained in this study we do believe that a possible explanation of the unfavorable complexation equilibria in CO2 based solvent systems could be a distorsion of the conformation of the cyclic oligosaccharides arising from the vanishing of the hydrogen bond interactions between contiguous glucose units of the peracetylated cyclodextrin.
Lingua originaleEnglish
pagine (da-a)154-160
Numero di pagine7
RivistaDefault journal
Volume49
Stato di pubblicazionePublished - 2009

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phosphine
Complexation
Carbon Dioxide
Equilibrium constants
Ligands
Phosphines
Cyclodextrins
Ultraviolet spectroscopy
Oligosaccharides
Titration
Temperature
Methanol
Conformations
Hydrogen bonds
Entropy
Derivatives
Glucose
betadex

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Cita questo

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title = "Complexation of phosphine ligands with peracetylated β-cyclodextrin insupercritical carbon dioxide: Effect of temperature and cosolvent on theequilibrium constant",
abstract = "The interaction between peracetylated -β-cyclodextrin and tert-butyl and adamantyl functionalized triphenylphosphine derivatives was studied in supercritical carbon dioxide (scCO2) based solvent mediaby UV–vis spectroscopy. The equilibrium constant for a 1:1 complexation reaction was obtained from titration spectra both in pure carbon dioxide and in the presence of methanol as a cosolvent in the temperaturerange 308–323K to estimate the internal energy and entropy of the inclusion equilibrium. The values of the equilibrium constants were found significantly smaller than those obtained in aqueous solution with analogous phosphines and substantially independent of the nature of the phosphine and of the solvent medium. On the basis of the results that we have obtained in this study we do believe that a possible explanation of the unfavorable complexation equilibria in CO2 based solvent systems could be a distorsion of the conformation of the cyclic oligosaccharides arising from the vanishing of the hydrogen bond interactions between contiguous glucose units of the peracetylated cyclodextrin.",
keywords = "Acetylated cyclodextrin, Complex stability constant, Inclusion complexes, Supercritical carbon dioxide, UV–vis absorption spectroscopy",
author = "Onofrio Scialdone and Alessandro Galia and Giuseppe Filardo and Eric Monflier and Navarre, {Edward Charles}",
year = "2009",
language = "English",
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TY - JOUR

T1 - Complexation of phosphine ligands with peracetylated β-cyclodextrin insupercritical carbon dioxide: Effect of temperature and cosolvent on theequilibrium constant

AU - Scialdone, Onofrio

AU - Galia, Alessandro

AU - Filardo, Giuseppe

AU - Monflier, Eric

AU - Navarre, Edward Charles

PY - 2009

Y1 - 2009

N2 - The interaction between peracetylated -β-cyclodextrin and tert-butyl and adamantyl functionalized triphenylphosphine derivatives was studied in supercritical carbon dioxide (scCO2) based solvent mediaby UV–vis spectroscopy. The equilibrium constant for a 1:1 complexation reaction was obtained from titration spectra both in pure carbon dioxide and in the presence of methanol as a cosolvent in the temperaturerange 308–323K to estimate the internal energy and entropy of the inclusion equilibrium. The values of the equilibrium constants were found significantly smaller than those obtained in aqueous solution with analogous phosphines and substantially independent of the nature of the phosphine and of the solvent medium. On the basis of the results that we have obtained in this study we do believe that a possible explanation of the unfavorable complexation equilibria in CO2 based solvent systems could be a distorsion of the conformation of the cyclic oligosaccharides arising from the vanishing of the hydrogen bond interactions between contiguous glucose units of the peracetylated cyclodextrin.

AB - The interaction between peracetylated -β-cyclodextrin and tert-butyl and adamantyl functionalized triphenylphosphine derivatives was studied in supercritical carbon dioxide (scCO2) based solvent mediaby UV–vis spectroscopy. The equilibrium constant for a 1:1 complexation reaction was obtained from titration spectra both in pure carbon dioxide and in the presence of methanol as a cosolvent in the temperaturerange 308–323K to estimate the internal energy and entropy of the inclusion equilibrium. The values of the equilibrium constants were found significantly smaller than those obtained in aqueous solution with analogous phosphines and substantially independent of the nature of the phosphine and of the solvent medium. On the basis of the results that we have obtained in this study we do believe that a possible explanation of the unfavorable complexation equilibria in CO2 based solvent systems could be a distorsion of the conformation of the cyclic oligosaccharides arising from the vanishing of the hydrogen bond interactions between contiguous glucose units of the peracetylated cyclodextrin.

KW - Acetylated cyclodextrin

KW - Complex stability constant

KW - Inclusion complexes

KW - Supercritical carbon dioxide

KW - UV–vis absorption spectroscopy

UR - http://hdl.handle.net/10447/42939

M3 - Article

VL - 49

SP - 154

EP - 160

JO - Default journal

JF - Default journal

ER -