Addition of CF2 group to endohedral fullerene Sc3N@Ih-C80
| Autor: | Olesya O. Semivrazhskaya, Nataliya A. Samoylova, Marco Rosenkranz, Alexey A. Popov, Alexey V. Rybalchenko, Anastasia D. Pykhova, Ilya N. Ioffe, Alexey A. Goryunkov |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Dalton Transactions. 49:9137-9147 |
| ISSN: | 1477-9234 1477-9226 |
| DOI: | 10.1039/d0dt01513j |
| Popis: | We report the first successful synthesis of a CF2 derivative of the stable endohedral fullerene Sc3N@Ih-C80. Reaction with CF2ClCOONa yields a single Cs-symmetric Sc3N@C80(CF2) adduct where the CF2 group is inserted into a [6,6]-bond and opens it to 2.3 A between the bridgehead carbon atoms. As evidenced by absorption and fluorescence spectroscopy as well as cyclic voltammetry, both the HOMO and the LUMO level of Sc3N@C80(CF2) are slightly (ca. 0.1 eV) downshifted with respect to the parent Sc3N@Ih-C80, so the HOMO-LUMO gap remains essentially unchanged. The DFT calculations suggest that the reaction mechanism is not the previously assumed [2 + 1]-cycloaddition of :CF2 carbene but rather nucleophilic addition of CF2Cl- anion followed by elimination of Cl- and closing of the CF2 bridge via intramolecular nucleophilic substitution. Selective formation of the [6,6]-Sc3N@C80(CF2) turns out to be kinetically controlled and promoted by a particular orientation of the endohedral Sc3N cluster with respect to the CF2Cl- addition site. In its turn, the CF2 addend partly hampers the rotation of Sc3N the endohedral cluster compared to its quasi-free reorientations in the parent Sc3N@Ih-C80. |
| Databáze: | OpenAIRE |
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