[6, 6]‐Open and [6, 6]‐Closed Isomers of C70(CF2): Synthesis, Electrochemical and Quantum Chemical Investigation. Issue 52 (18th November 2013)

• Record Type: Journal Article
• Authors: Samoylova, Nataliya A.; Belov, Nikita M.; Brotsman, Victor A.; Ioffe, Ilya N.; Lukonina, Natalia 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.
• Is Part Of: Chemistry. Volume 19:Issue 52(2013)
• Page Start: 17969
• Page End: 17979
• Publication Date: 2013-11-18
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201302946
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Novel difluoromethylenated [70]fullerene derivatives, C<sub>70</sub>(CF<sub>2</sub>)<sub><italic>n</italic></sub> (<italic>n</italic>=1–3), were obtained by the reaction of C<sub>70</sub> with sodium difluorochloroacetate. Two major products, isomeric C<sub>70</sub>(CF<sub>2</sub>) 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<sub>70</sub>(CF<sub>2</sub>) 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<sub>70</sub>(CF<sub>2</sub>) 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<sub>70</sub>. In situ ESR spectroelectrochemical investigation of the C<sub>70</sub>(CF<sub>2</sub>) 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<sub>70</sub>(CF<sub>2</sub>) constitutes an interesting example of a redox‐switchable fullerene derivative.</p> </abstract>