Counterion-Controlled Self-Sorting in an Amphiphilic Calixarene Micellar System

Silvia Fernández-Abad, Márcia Pessêgo, Nuno Basílio, Luis García-Río

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Molecular recognition of small molecules and ions by artificial receptors in microheterogeneous media such as micelles and vesicles can, in principle, provide better models of biological systems in comparison with bulk solutions. In this work we have investigated the complexation of an organic fluorescent probe with amphiphilic calixarene receptor below and above the critical micelle concentration (CMC). For concentrations below the CMC, the probe forms a host-guest complex with the calixarene behaving like a traditional host-guest system operating in bulk solution. Above the CMC, multiple equilibrium processes are established and the probe can exchange between the recognition site of the calixarene in the monomeric state, micellized state and/or the micellar hydrophobic core. Careful analysis of the results obtained from NMR spectroscopy and fluorescence experiments allowed us to propose a quantitative model to describe the system. The increment of the local concentration of Na+ counterions at the Stern layer displace the dye to the micelle core through competitive binding of Na+ in the cavity of the receptor and is decisive for the observed self-sorting behavior. The sort code: In this work the complexation of an organic fluorescent probe with an amphiphilic calixarene receptor below and above the critical micelle concentration was investigated. It was found that guest translocation from the host cavity to the micellar core is affected by competitive counterion binding and is decisive for the self-sorting behavior.

Original languageEnglish
Pages (from-to)6466-6470
Number of pages5
JournalChemistry-A European Journal
Volume22
Issue number19
DOIs
Publication statusPublished - 4 May 2016

Keywords

  • calixarene
  • host-guest interactions
  • micelle
  • self-sorting
  • supramolecular chemistry

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