First Synthesis and Characterization of CH₄ @C₆₀

Area of Science:

• Supramolecular Chemistry
• Nanotechnology
• Organic Chemistry

Background:

• Fullerenes, like C60, are carbon-based molecules with unique cage structures.
• Encapsulating molecules within fullerenes (endohedral fullerenes) presents challenges, especially for larger guests.
• Previous endohedral fullerene syntheses have been limited to smaller atoms or molecules.

Purpose of the Study:

• To synthesize the endohedral fullerene CH4@C60 for the first time.
• To investigate the feasibility of encapsulating organic molecules within the C60 cage.
• To characterize the structure and dynamics of the encapsulated methane molecule.

Main Methods:

• Photochemical desulfinylation of an open fullerene precursor.
• Synthesis of the endohedral fullerene CH4@C60.
• X-ray crystallography to determine the crystal structure.
• Proton spin-lattice relaxation time (T1) measurements.

Main Results:

• Successful synthesis of CH4@C60, encapsulating methane within the C60 cage.
• The C60 cage structure remains largely undistorted.
• Methane exhibits quantum behavior and free rotation within the fullerene cage.
• The synthesis was achieved despite inhibition by the endohedral molecule during a key step.

Conclusions:

• Methane is the largest organic molecule encapsulated in C60 to date.
• The synthesis method is viable for incorporating larger guest molecules into fullerenes.
• This work paves the way for creating novel endofullerenes with diverse applications.