Supramolecular Shish Kebabs: Higher Order Dimeric Structures from Ring-in-Rings Complexes with Conformational...

Area of Science:

• Supramolecular Chemistry
• Chemical Systems
• Materials Science

Background:

• Understanding higher-order superstructures in abiotic chemical systems presents significant challenges.
• Self-assembly of molecular components is crucial for creating complex structures.

Purpose of the Study:

• To report a novel ring-in-ring system for constructing discrete higher-order superstructures.
• To explore the adaptive conformational properties of these assembled structures.

Main Methods:

• Utilized a hydrogen-bonded macrocycle in conjunction with cyclobis(paraquat-o-phenylene) (o-Box) or cyclobis(paraquat-p-phenylene) (p-Box) tetracations.
• Employed mass spectrometry, computational modeling, NMR spectroscopy, and single-crystal X-ray diffraction for analysis.

Main Results:

• The ring-in-ring system demonstrated box-directed aggregation of macrocycles, forming stable species like H4G and H5G.
• A unique dimeric shish-kebab-like superstructure (H7G2 or H8G2) was formed via coaxial stacking of two ring-in-ring units.
• The formation of dimeric superstructures was attributed to the large π-surface of the macrocycle and conformational variations.

Conclusions:

• The developed ring-in-ring system successfully constructs discrete higher-order superstructures with adaptive conformations.
• The study highlights the potential of such systems in creating complex molecular architectures.
• Conformational adaptability and π-surface interactions are key factors in the formation of unique dimeric superstructures.