Reversible morphological changes of assembled supramolecular amphiphiles triggered by pH-modulated host–guest interactions
| Autor: | D. K. Gaspar, M. Vazquez, J. R. Thompson, Andrew C.-H. Sue, T. J. Dawson, Marco S. Messina, Jessica A. Lehrman, Amanda N. Goldner, Mark A. Olson |
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| Rok vydání: | 2016 |
| Předmět: |
Chemistry
Stereochemistry Organic Chemistry Supramolecular chemistry Protonation 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry Micelle 0104 chemical sciences Dication Crystallography chemistry.chemical_compound Molecular recognition Pulmonary surfactant Amphiphile Physical and Theoretical Chemistry 0210 nano-technology Ethylene glycol |
| Zdroj: | Organic & Biomolecular Chemistry. 14:5714-5720 |
| ISSN: | 1477-0539 1477-0520 |
| Popis: | Reversible template-directed micellar-size and shape modulation by virtue of host-guest reversible docking of molecular templates at the micellar-solvent interface was achieved in water. By combining a π-electron deficient bipyridinium-based gemini amphiphile which is capable of binding and aligning with a π-electron rich tri(ethylene glycol)-disubstituted 1,5-diaminonaphthalene, a switchable detergent system which operates through the pH-responsive formation of bisammonium dications was realised. The binding of the 1,5-diaminonaphthalene guest to the bipyridinium-based micellar aggregate superstructure can be actuated by the addition of acid and base. Upon the addition of acid, protonation of the guest forming the dication deactivates molecular recognition with the charged head groups of the micellar aggregate by Coulombic repulsion. This process is completely reversible upon the addition of base, whereby the guest reintercalates into the superstructure -again forming donor-acceptor π-π stacks at the micellar-solvent interface amongst contiguous surfactant head groups. Synchrotron small angle X-ray scattering and dynamic laser light scattering confirm that this form of reversible directionally-templated micellisation results in an oblate spheroid-to-lamellar micelle morphological transition with a stabilising net decrease in the free energy of micellisation of 1.4 kcal mol(-1) per hydrophobic tail. |
| Databáze: | OpenAIRE |
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