A Giant Carceplex Permanently Entraps Three Organic Molecules

Area of Science:

• Supramolecular Chemistry
• Host-Guest Chemistry

Background:

• Cavitands are molecular "hosts" capable of encapsulating guest molecules.
• Carceplexes represent a class of mechanically bound host-guest complexes with unique structural properties.

Purpose of the Study:

• To synthesize and characterize a large carceplex capable of encapsulating multiple guest molecules.
• To investigate the dynamic behavior of entrapped N,N-dimethylformamide (DMF) molecules within the carceplex cavity.

Main Methods:

• Synthesis of a trimer of cavitands capped to form a carceplex.
• Nuclear Magnetic Resonance (NMR) spectroscopy at variable temperatures.
• Computational modeling using CPK (Corey-Pauling-Koltun) representations.

Main Results:

• Successful formation of a carceplex containing three permanently entrapped N,N-dimethylformamide (DMF) molecules.
• NMR data indicates significant mobility of DMF molecules within the carceplex at room temperature, suggesting a "microsolvent" effect.
• At lower temperatures, distinct binding sites for the DMF molecules within the carceplex cavity were resolved.

Conclusions:

• The synthesized carceplex effectively entraps guest molecules, creating a confined environment.
• The dynamic nature of the entrapped DMF molecules highlights the potential of carceplexes as artificial "microsolvent" systems.
• Variable temperature NMR is a powerful tool for probing molecular dynamics within supramolecular hosts.