[60]Fullerene adducts with improved electron acceptor properties [In Process Citation]

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Fullerenes, particularly C(60), are potent electron acceptors with unique electronic properties.
• Functionalization of C(60) can tune its electronic and structural characteristics for specific applications.
• Electron acceptor moieties like quinones, TCNQ, and DCNQI derivatives are crucial in charge-transfer systems.

Purpose of the Study:

• To synthesize novel C(60)-based dyads by covalently linking strong electron acceptors to the C(60) core.
• To investigate the electronic properties of these dyads, specifically focusing on their redox potentials.
• To understand the impact of the C(60) core on the electron acceptor moiety and vice versa.

Main Methods:

• 1,3-dipolar cycloaddition reactions involving in situ generated azomethyne ylides or nitrile oxides with C(60).
• Synthesis of pyrrolidino[3", 4":1,2][60]fullerenes and isoxazolo[4", 5":1,2][60]fullerenes.
• Electrochemical analysis (cyclic voltammetry) to determine reduction potentials.
• Semiempirical PM3 molecular geometry calculations for selected pyrrolidinofullerene derivatives.

Main Results:

• Pyrrolidinofullerenes exhibited cathodically shifted reduction potentials compared to pristine C(60).
• Isoxazolofullerenes displayed anodically shifted reduction potentials, indicating stronger electron acceptor capabilities than C(60).
• The electron acceptor moiety in isoxazolofullerenes showed an anodic shift due to electronic interaction with the C(60) core.
• Molecular modeling revealed significant distortion in the acceptor moiety of a specific pyrrolidinofullerene (compound 13) and a stable conformation positioning dicyanomethylene units away from the C(60) surface.

Conclusions:

• The covalent attachment of electron acceptors to C(60) effectively modulates the electronic properties of the fullerene core.
• Isoxazolofullerenes represent a class of enhanced electron acceptors with potential applications in organic electronics.
• The electronic interplay between the C(60) core and the appended acceptor moiety influences their respective redox behaviors and molecular conformations.