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[6,6]‐Open and [6,6]‐Closed Isomers of C 70 (CF 2 ): Synthesis, Electrochemical and Quantum Chemical Investigation
Author(s) -
Samoylova Nataliya A.,
Belov Nikita M.,
Brotsman Victor A.,
Ioffe Ilya N.,
Lukonitalia S.,
Markov Vitaliy Yu.,
Ruff Adrian,
Rybalchenko Alexey V.,
Schuler Paul,
Semivrazhskaya Olesya O.,
Speiser Bernd,
Troyanov Sergey I.,
Magdesieva Tatiana V.,
Goryunkov Alexey A.
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302946
Subject(s) - fullerene , chemistry , electrochemistry , adduct , electron transfer , redox , derivative (finance) , radical ion , electron paramagnetic resonance , photochemistry , medicinal chemistry , inorganic chemistry , organic chemistry , electrode , nuclear magnetic resonance , ion , physics , financial economics , economics
Novel difluoromethylenated [70]fullerene derivatives, C 70 (CF 2 ) n ( n =1–3), were obtained by the reaction of C 70 with sodium difluorochloroacetate. Two major products, isomeric C 70 (CF 2 ) mono‐adducts with [6,6]‐open and [6,6]‐closed configurations, were isolated and their homofullerene and methanofullerene structures were reliably determined by a variety of methods that included X‐ray analysis and high‐level spectroscopic techniques. The [6,6]‐open isomer of C 70 (CF 2 ) constitutes the first homofullerene example of a non‐hetero [70]fullerene derivative in which functionalisation involves the most reactive bond in the polar region of the cage. Voltammetric estimation of the electron affinity of the C 70 (CF 2 ) isomers showed that it is substantially higher for the [6,6]‐open isomer (the 70‐electron π‐conjugated system is retained) than the [6,6]‐closed form, the latter being similar to the electron affinity of pristine C 70 . In situ ESR spectroelectrochemical investigation of the C 70 (CF 2 ) radical anions and DFT calculations of the hyperfine coupling constants provide evidence for the first example of an inter‐conversion between the [6,6]‐closed and [6,6]‐open forms of a cage‐modified fullerene driven by an electrochemical one‐electron transfer. Thus, [6,6]‐closed C 70 (CF 2 ) constitutes an interesting example of a redox‐switchable fullerene derivative.