Dimeric capsules with a nanoscale cavity for [60]fullerene encapsulation

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Nanotechnology

Background:

• Resorcinarene derivatives are known for their ability to form host-guest complexes.
• Fullerenes, such as C60, are unique nanosized molecules with diverse applications.
• Controlling the self-assembly of molecular structures is crucial for developing advanced materials.

Purpose of the Study:

• To investigate the acid-assisted and guest-induced formation of superstructures using resorcinarene derivatives and fullerenes.
• To characterize the self-assembled structures and understand the encapsulation mechanism of nanosized guest molecules.
• To explore the factors influencing the fullerene encapsulation process.

Main Methods:

• Addition of haloacetic acids and [60]fullerenes to a toluene solution of resorcinarene derivative 1.
• Spectroscopic analysis (including 2D exchange NMR) to determine the structure and dynamics of the formed complexes.
• Fluorescence spectroscopy to probe the environmental changes around the encapsulated fullerene.

Main Results:

• Formation of dimeric superstructures encapsulating [60]fullerenes was achieved.
• The self-assembled complexes (structure 2) are stabilized by pyridinium-anion-pyridinium, pi-pi, and van der Waals interactions.
• Decomplexation rate of the fullerene complex was determined to be 3.1 s(-1).
• Fullerene encapsulation is controllable by adjusting acid amounts, temperature, acid/base ratio, and solvent polarity.
• Encapsulation induces spectral changes in fluorescence, indicating altered microenvironment around the fullerene.

Conclusions:

• Acid and guest co-addition enables controlled formation of fullerene-encapsulated resorcinarene superstructures.
• The self-assembly process is driven by specific intermolecular interactions.
• The study demonstrates tunable control over fullerene encapsulation, opening possibilities for molecular recognition and encapsulation applications.