Unexpected formation of a Sc3C2@C80 bisfulleroid derivative

Area of Science:

• Fullerene chemistry
• Organometallic chemistry
• Supramolecular chemistry

Background:

• Fullerenes are carbon-based molecules with unique electronic and structural properties.
• Metal-containing fullerenes, such as Sc(3)C(2)@C(80), offer potential for novel applications.
• Reactions with fullerenes can lead to diverse derivatives, including open-cage structures.

Purpose of the Study:

• To investigate the reaction of tetrazine with the metal-containing fullerene Sc(3)C(2)@C(80).
• To determine the structure of the resulting product and compare it to reactions with pristine fullerenes.
• To explore the initial steps of metal atom release from endohedral fullerenes.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy for structural elucidation.
• Density Functional Theory (DFT) calculations for theoretical validation.
• Electron Paramagnetic Resonance (EPR) spectroscopy to probe metal atom location.

Main Results:

• The reaction exclusively produced an open-cage derivative (2), not the expected C(2)-inserted product (3).
• The structure of the open-cage derivative was confirmed by NMR and theoretical calculations.
• EPR spectroscopy revealed a single scandium atom positioned within the cage bulge, indicating a step towards metal atom release.

Conclusions:

• The reaction pathway differs significantly from that observed with pristine C(60).
• The formation of the open-cage structure is a key finding in fullerene chemistry.
• This work represents a significant step towards understanding and controlling the release of encapsulated metal atoms from endohedral fullerenes.