Record Alkali Metal Intercalation by Highly Charged Corannulene.

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Energy Storage

Background:

• Advanced energy storage requires novel functional materials.
• Bowl-shaped polycyclic aromatic hydrocarbons (buckybowls) are promising candidates due to their ability to accept multiple electrons.
• Corannulene (C20H10) is a key example of a buckybowl with unique electronic properties.

Purpose of the Study:

• To elucidate the supramolecular structure of reduced corannulene with lithium ions.
• To investigate mixed alkali metal reduction and self-assembly reactions of corannulene.
• To explore the potential of buckybowls as ligands for metal ion storage.

Main Methods:

• X-ray crystallography
• NMR spectroscopy
• Theoretical calculations (DFT)
• Experimental characterization of organometallic supramolecules

Main Results:

• Resolved the structure of tetrareduced corannulene (C20H10^4-) with lithium ions, revealing a new lithium intercalation paradigm.
• Discovered cooperative effects of lithium with heavier alkali metals (K, Rb, Cs) in corannulene reduction and assembly.
• Synthesized and characterized novel triple-decker supramolecular assemblies (e.g., Li3M3^6+, LiM5^6+) with record metal ion intercalation capacity.
• Observed unprecedented internal lithium binding and significant negative shifts in 7Li NMR spectra.

Conclusions:

• Bowl-shaped π-ligands like corannulene exhibit remarkable potential for alkali metal storage.
• The unique electronic structures of these negatively charged buckybowls enable novel supramolecular chemistry.
• This research opens new avenues for designing advanced materials for energy storage applications.