Acid-base controllable recognition properties of a highly versatile calix[6]crypturea

Area of Science:

• Supramolecular Chemistry
• Host-Guest Chemistry
• Organic Chemistry

Background:

• Designing receptors with tunable binding properties is challenging.
• Stimuli-responsive molecular recognition is crucial for advanced materials and sensing.
• Heteroditopic receptors offer complex binding capabilities.

Purpose of the Study:

• To synthesize and characterize a novel calix[6]crypturea receptor.
• To investigate the binding capabilities and selectivity of the receptor for various guests.
• To demonstrate the acid-base controllable nature and potential applications in supramolecular switches.

Main Methods:

• Synthesis of calix[6]crypturea (1).
• Nuclear Magnetic Resonance (NMR) spectroscopy for binding studies.
• Evaluation of host-guest interactions and selectivity.

Main Results:

• Compound 1 acts as a versatile host for neutral molecules, anions, and ion pairs.
• High selectivity observed for hydrogen-bond donors/acceptors, chloride anions, and ammonium ions.
• Acid-base control allows for tunable recognition and induced-fit binding of large guests like neurotransmitters.

Conclusions:

• The calix[6]crypturea receptor exhibits unique, acid-base controllable host properties.
• Selective guest-switching is achievable through protonation.
• The receptor enables the development of sophisticated supramolecular switches.