![Quantitative SERS Detection of Uric Acid via Formation of Precise Plasmonic Nanojunctions within Aggregates of Gold Nanoparticles and Cucurbit[n]uril](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F61682.jpg&w=3840&q=50)
Strong Emission Enhancement in pH-Responsive 2:2 Cucurbit[8]uril Complexes
Stefan Schoder1, Hendrik V Schröder1, Luca Cera1
1Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|January 13, 2019
Summary
Researchers developed new bipyridinium fluorophores that overcome quenching issues. Encapsulation in cucurbiturils creates a switchable supramolecular system with enhanced fluorescence, useful for various applications.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- Organic fluorophores are vital for biological and material sciences.
- Photoluminescence quenching due to aggregation and rotation limits their application.
- Stimuli-responsive fluorophores offer dynamic control over optical properties.
Purpose of the Study:
- To develop easily accessible bipyridinium fluorophores.
- To investigate their photoluminescence properties when encapsulated in cucurbiturils.
- To create a switchable supramolecular fluorescence system.
Main Methods:
- Synthesis of bipyridinium fluorophores.
- Formation of 1:1 and 2:2 complexes with cucurbit[7]uril and cucurbit[8]uril.
- Photoluminescence spectroscopy to analyze fluorescence enhancement.
- Investigation of pH-switchable properties.
Main Results:
- Bipyridinium fluorophores exhibit emission quenched by a twisted intramolecular charge-transfer (TICT) mechanism.
- Encapsulation in cucurbit[7]uril moderately increases emission by destabilizing the TICT state.
- Complexation with cucurbit[8]uril significantly enhances fluorescence via conformational restriction.
- The cucurbituril complexes demonstrate efficient pH-switchable ON/OFF fluorescence behavior.
Conclusions:
- Supramolecular encapsulation in cucurbiturils effectively modulates the photoluminescence of bipyridinium fluorophores.
- The developed system acts as an efficient and switchable supramolecular fluorescence ON/OFF system.
- This offers potential for advanced sensing and imaging applications.
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