Phosphine-Mediated Dimerization of Open-[60]Fullerenes

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry

Background:

• The reaction of trimethylphosphine with open-[60]fullerene typically leads to deoxygenation.
• Standard Wittig reactions and aldol condensations were inefficient, suggesting an alternative dimerization mechanism.

Purpose of the Study:

• To elucidate the unknown dimerization pathway of open-[60]fullerene.
• To computationally investigate the proposed role of 1-phosphonium-3-carbabetaine in dimer formation.

Main Methods:

• Computational examination of reaction pathways.
• Analysis of intermediate species, including 1-phosphonium-3-carbabetaine.

Main Results:

• The formation of β-oxo-phosphorous ylide and α-methylene carbonyl derivatives was observed.
• A proposed pathway involves the betaine intermediate undergoing nucleophilic addition to another open-[60]fullerene molecule.
• This forms an epoxide dimer, which is then deoxygenated to yield the final open-[60]fullerene dimer.

Conclusions:

• The study proposes a novel computational mechanism for open-[60]fullerene dimerization.
• 1-phosphonium-3-carbabetaine is identified as a crucial intermediate in this pathway.
• This finding advances the understanding of fullerene functionalization reactions.