γ-Cyclodextrin modulates the chemical reactivity by multiple complexation

J. Fernández-Rosas, M. Pessêgo, M. Cepeda-Plaza, N. Basilio, M. Parajó, P. Rodríguez-Dafonte, L. García-Río

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Abstract

Multiple complexation by γ-CD has been studied by self-diffusion coefficients (DOSY) and chemical kinetics experiments in which 4-methoxybenzenesulfonyl chloride (MBSC) solvolysis was used as a chemical probe. The addition of a surfactant as a third component to the reaction mixture induced a very complex reactivity pattern that was explained on the basis of multiple complexation phenomena and surfactant self-assembly to form micelles. A cooperative effect that yielded a ternary complex formed by cyclodextrin-surfactant-MBSC was observed. The larger cavity of γ-CD in comparison with β-CD is responsible for the change from the competitive complexation mechanism predominant with β-CD to a cooperative/competitive mixed mechanism operating for the larger derivative. The cavity size in γ-CD is large enough to bind two surfactant alkyl chains with a cooperative effect. Water molecules released by the formation of 1 : 1 host-guest complexes made the cavity more hydrophobic and promoted further inclusion. A reduction in the available volume of the cavity should be considered on binding a second guest.

Original languageEnglish
Pages (from-to)1213-1224
Number of pages12
JournalOrganic & Biomolecular Chemistry
Volume13
Issue number4
DOIs
Publication statusPublished - 28 Jan 2015

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Keywords

  • ROOM-TEMPERATURE PHOSPHORESCENCE
  • SODIUM DODECYL-SULFATE
  • HOST-GUEST COMPLEXES
  • BETA-CYCLODEXTRIN
  • AQUEOUS-SOLUTIONS
  • INCLUSION COMPLEXES
  • ALPHA-CYCLODEXTRIN
  • SURFACTANT COMPLEXATION
  • MOLECULAR-DYNAMICS;
  • BASIC HYDROLYSIS

Cite this

Fernández-Rosas, J., Pessêgo, M., Cepeda-Plaza, M., Basilio, N., Parajó, M., Rodríguez-Dafonte, P., & García-Río, L. (2015). γ-Cyclodextrin modulates the chemical reactivity by multiple complexation. Organic & Biomolecular Chemistry, 13(4), 1213-1224. https://doi.org/10.1039/c4ob02113d