Fullerene cyanation does not always increase electron affinity: an experimental and theoretical study.

Area of Science:

• * Supramolecular chemistry and materials science.
• * Focus on fullerene derivatives and their electronic properties.

Background:

• * Fullerenes, particularly C70, are of interest due to their unique electronic structures.
• * Understanding the impact of functional groups on fullerene properties is crucial for designing new materials.

Purpose of the Study:

• * To experimentally and theoretically investigate the electron affinities of C70 derivatives.
• * To determine the electronic effects of trifluoromethyl, methyl, and cyano functional groups on C70.
• * To report the synthesis of a novel C70 fullerene derivative.

Main Methods:

• * Low-temperature photoelectron spectroscopy (LT PES) for experimental measurements.
• * Density functional theory (DFT) for theoretical calculations.
• * Synthesis and characterization of new fullerene derivatives.

Main Results:

• * Electron affinities were found to be highly dependent on the addition patterns of functional groups.
• * Substitution of trifluoromethyl (CF3) for cyano (CN) groups increased experimental electron affinity by 70 meV per substitution.
• * A new fullerene derivative, C70(CF3)10(CN)2, was successfully synthesized.

Conclusions:

• * The electronic effects of functional groups on C70 derivatives are significant and pattern-dependent.
• * Trifluoromethyl and cyano groups can be strategically used to tune the electron affinity of C70.
• * The newly synthesized C70(CF3)10(CN)2 represents a novel material with potential applications.