Trifluoromethylation of C₆₀ and C₇₀ with Mercury(II) Trifluoroacetate

Abstract

Fullerenes C₆₀ and C₇₀ are shown to react with Hg(CF₃COO)₂ in the ionization chamber of the electron impact source of a mass spectrometer at 300 and 310°C, yielding trifluoromethylated derivatives of the fullerenes with up to six and two CF₃ addends, respectively. For some of the products the reactions are accompanied by hydrogen addition. Based on previous mechanistic studies of the analogous reactions of C₆₀ with the Scherer radical (C₉F₁₉•), a mixture of perfluoronones (C₉F₁₈), and acetone, a plausible scheme is proposed for the processes. It involves formation of the intermediate CF₃ radicals owing to electron impact or thermally initiated homolytic dissociation of the mercury(II) salt, and their further reaction with the fullerenes at the surface of the ionization chamber. Heating mixtures of the reagents under argon at 300–310°C also yields trifluoromethylated fullerenes, in agreement with the results obtained with the ionization chamber.

*Deceased on 1 February 2006

Keywords:

• C₆₀
• C₇₀
• Mercury(II) trifluoroacetate
• Reactive mass spectrometry
• Trifluoromethylation of fullerenes

ACKNOWLEDGMENTS

The authors are grateful to RFBR (grant No. 03‐0332695), IPTI RAS (project 9/02) and Presidium of RAS (project P‐1) for financial support of this study. We also wish to express their gratitude to Dr C. D. Latham at the University of Sussex, UK, for his valuable comments and suggestions made during the course of this work.

We also wish to record with great sadness the death of our friend and colleague, Roger Taylor, which occurred before the completion of this article. He worked with us tirelessly until the end.

Notes

*Deceased on 1 February 2006