A Multiresponsive Calix[6]arene Pseudorotaxane Empowered by Fluorophoric Dansyl Groups

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Materials Science

Background:

• Calixarenes are macrocyclic compounds known for their complexation abilities.
• Dansyl groups can be used as fluorescent probes and can undergo reversible protonation.
• Bipyridinium units are guests in supramolecular chemistry, often involved in redox processes.

Purpose of the Study:

• To synthesize and characterize a novel dansyl calix[6]arene derivative.
• To create and investigate a pseudorotaxane complex using this derivative and a bipyridinium axle.
• To explore the multiresponsive nature of the pseudorotaxane system.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy for structural elucidation.
• UV-visible spectroscopy for electronic property analysis.
• Electrochemical techniques to study redox behavior and complex stability.

Main Results:

• Successful synthesis and characterization of the dansyl calix[6]arene and its pseudorotaxane complex.
• Demonstration of fluorescence signaling by the dansyl moieties.
• Reversible protonation of the calixarene host modulates complexation.
• Photoinduced electron transfer processes tune supramolecular complex stability.

Conclusions:

• The synthesized pseudorotaxane exhibits multiresponsive behavior.
• Molecular movements within the pseudorotaxane can be controlled by three orthogonal stimuli: protonation, electrochemical reduction, and photoinduced electron transfer.
• This system offers tunable control over supramolecular assembly and disassembly.