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Updated: Jul 14, 2026
09:22
Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
Surface-immobilized pyridine-functionalized gamma-cyclodextrin: alkanethiol co-adsorption-induced reorientation
Colm T Mallon1, Robert J Forster, Andrea McNally
1National Center for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
Langmuir : the ACS Journal of Surfaces and Colloids
|May 25, 2007
Summary
Self-assembled monolayers of functionalized gamma-cyclodextrins (gamma-CD-(py)2) on platinum electrodes show tunable properties. Backfilling with 1-nonanethiol enhances blocking and enables molecular recognition of guests, demonstrating controlled supramolecular assembly.
Area of Science:
- Supramolecular Chemistry
- Electrochemistry
- Surface Science
Background:
- Cyclodextrins (CDs) are widely used in host-guest chemistry.
- Self-assembled monolayers (SAMs) on electrodes offer platforms for molecular studies.
- Functionalized CDs can be immobilized on surfaces to create novel interfaces.
Purpose of the Study:
- To investigate the electrochemical and surface properties of gamma-cyclodextrin (gamma-CD-(py)2) monolayers on platinum.
- To explore the effects of backfilling with 1-nonanethiol on the properties of these monolayers.
- To demonstrate the control over molecular recognition and electrochemical activity through surface modification.
Main Methods:
- Formation of self-assembled monolayers (SAMs) of gamma-CD-(py)2 and 1-nonanethiol on polycrystalline platinum electrodes.
- Electrochemical techniques including capacitance measurements.
- Surface-enhanced Raman spectroscopy (SERS) for structural analysis.
- Electrochemical studies using solution-phase probes like [Fe(CN)6]4- and electroactive guests like [Co(biptpy)2]2+.
Main Results:
- Backfilled gamma-CD-(py)2 layers exhibit higher capacitance, suggesting ion flux through the CD cavity.
- SERS spectra confirm the presence of both CD and alkane moieties in backfilled layers.
- Backfilled layers show enhanced blocking properties compared to bare gamma-CD-(py)2 films.
- Molecular recognition and electrochemical activity of [Co(biptpy)2]2+ are 'switched on' by backfilling, indicating reorientation of CDs.
- Binding of [Co(biptpy)2]2+ follows Langmuir adsorption kinetics, yielding association constants and surface coverages.
Conclusions:
- Self-assembled monolayers of functionalized gamma-cyclodextrins can be controllably modified by backfilling with alkanethiols.
- Surface modification significantly impacts the electrochemical properties and blocking capabilities of the monolayers.
- Backfilling induces a conformational change in the cyclodextrins, enabling host-guest complex formation and electrochemical response.
- These findings provide a pathway for designing switchable molecular recognition interfaces on electrode surfaces.
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