Addition of CF2 group to endohedral fullerene Sc3N@Ih-C80. Issue 26 (24th June 2020)

• Record Type: Journal Article
• Authors: Pykhova, Anastasia D.; Semivrazhskaya, Olesya O.; Samoylova, Nataliya A.; Rybalchenko, Alexey V.; Rosenkranz, Marco; Ioffe, Ilya N.; Popov, Alexey A.; Goryunkov, Alexey A.
• Is Part Of: Dalton transactions. Volume 49:Issue 26(2020)
• Page Start: 9137
• Page End: 9147
• Publication Date: 2020-06-24
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d0dt01513j
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : [6, 6]-Open C s -Sc3 N@C80 CF2 adduct is formed in reaction of Sc3 N@ I h -C80 with CF2 ClCOONa. CF2 addition imposes considerable restrictions on the Sc3 N motion inside the carbon cage. DFT calculations suggest that the reaction pathway is nucleophilic rather than carbenic. Abstract : We report the first successful synthesis of a CF2 derivative of the stable endohedral fullerene Sc3 N@ I h -C80 . Reaction with CF2 ClCOONa yields a single C s -symmetric Sc3 N@C80 (CF2 ) adduct where the CF2 group is inserted into a [6, 6]-bond and opens it to 2.3 Å 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 Sc3 N@C80 (CF2 ) are slightly ( ca. 0.1 eV) downshifted with respect to the parent Sc3 N@ I h -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 CF2 Cl − anion followed by elimination of Cl − and closing of the CF2 bridge via intramolecular nucleophilic substitution. Selective formation of the [6, 6]-Sc3 N@C80 (CF2 ) turns out to be kinetically controlled and promoted by a particular orientation of the endohedral Sc3 N cluster with respect to the CF2 Cl − addition site. In its turn, the CF2 addend partly hampers the rotation of Sc3 N the endohedral cluster compared to its quasi-free reorientations in the parent Sc3 N@ I h -C80 .