Formation of ring-in-ring complexes between crown ethers and rigid TVBox(8+)

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Materials Science

Background:

• Cyclophanes are versatile molecular hosts with tunable cavities.
• Tetraviologen-based macrocycles offer unique electronic properties due to their cationic nature.

Purpose of the Study:

• To synthesize and characterize a novel rigid octacationic tetraviologen-based cyclophane.
• To investigate the guest encapsulation capabilities of the synthesized cyclophane.

Main Methods:

• Synthesis of the octacationic tetraviologen cyclophane.
• Characterization using NMR spectroscopy and X-ray crystallography.
• Host-guest binding studies using various aromatic molecules.

Main Results:

• A rigid octacationic tetraviologen cyclophane, (8+), was successfully synthesized.
• The cyclophane features a rectangular cavity (23 Å x 6.1 Å) with a highly electron-deficient interior.
• Demonstrated simultaneous encapsulation of two small aromatic guests (e.g., toluene, chlorobenzene) or one large guest (e.g., bis-1,5-dinaphtho[50]crown-14).

Conclusions:

• The reported cyclophane represents a new class of rigid, electron-deficient hosts.
• Its unique cavity dimensions and electronic properties enable selective encapsulation of small or large guest molecules.
• This work expands the scope of supramolecular hosts for molecular recognition and encapsulation applications.