Theoretical Insight into Thermodynamically Optimal U@C₈₄: Three-Electron Transfer Rather Than Four-Electron Transfer

Area of Science:

• Computational Chemistry
• Materials Science
• Nanotechnology

Background:

• Electron transfer in uranium-fullerene complexes (U@Cn) is crucial for understanding their properties.
• Previous studies focused on U@C2n (2n < 82) and U@C82, with varying electron transfer mechanisms.
• U@C84 has been detected experimentally but lacks detailed theoretical investigation.

Purpose of the Study:

• To investigate the electronic structure and properties of U@C84 isomers using advanced computational methods.
• To identify thermodynamically stable U@C84 isomers and elucidate their electron transfer characteristics.
• To predict potential reaction sites for functionalization and explore applications of U@C84.

Main Methods:

• Detailed quantum-chemical calculations.
• Statistical thermodynamic analysis.
• Infrared (IR) absorption spectra simulation.

Main Results:

• Identification of three thermodynamically optimal U@C84 isomers: U@C2(51579)-C84, U@D2(51573)-C84, and U@C(51365)-C84.
• Observation of unexpected three-electron transfers in all studied isomers, resulting in an unpaired electron on the fullerene cage.
• Progressive weakening of covalent interactions between uranium and the fullerene cage in the order U@D2(51573)-C84 < U@C2(51579)-C84 < U@C(51365)-C84.
• Simulation of IR spectra to aid experimental identification.

Conclusions:

• The study elucidates the electronic structure and stability of novel U@C84 isomers.
• Unexpected three-electron transfer mechanisms are identified, differing from previously studied U@Cn systems.
• Predicted reaction sites suggest potential for U@C84 functionalization and diverse applications.