Crystallographic determination of Lu@C_2v(9)-C₈₂: electronic configuration and encapsulation energy-driven formation...

Area of Science:

• Fullerenes Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• The study of lanthanide metallofullerenes often focuses on dimeric forms like Lu2@C82.
• Monomeric Lu@C82 has been less understood, particularly regarding its electronic structure and formation.
• Resolving the valence paradox of Lu@C82 is crucial for understanding lanthanide fullerene interactions.

Purpose of the Study:

• To isolate and structurally characterize the monomeric lutetium metallofullerene, Lu@C82.
• To elucidate the electronic interactions between the lutetium ion and the C82 fullerene cage.
• To explain the preferential formation of dimeric Lu2@C82 over monomeric Lu@C82.

Main Methods:

• Isolation and structural identification of Lu@C82 using advanced spectroscopic techniques.
• Density Functional Theory (DFT) calculations to model electronic structure and bonding.
• Development of an encapsulation energy descriptor to analyze formation preferences.

Main Results:

• Lu@C82 was successfully isolated and identified as Lu3+@[C2v(9)-C82]3-.
• Spectroscopic and DFT analyses revealed that metal-cage electrostatics dominate over the 6s orbital contraction of lutetium.
• A novel encapsulation energy descriptor was established, successfully explaining the preference for Lu2@C82 formation.

Conclusions:

• The electronic structure of Lu@C82 is governed by strong metal-cage electrostatic interactions.
• The encapsulation energy descriptor provides a new framework for understanding lanthanide metallofullerene nuclearity.
• This work resolves the long-standing valence paradox associated with Lu@C82 and clarifies formation trends in lanthanide metallofullerenes.