Difluoromethylenation of fullerene C70 provides isomeric diversity and availability of equatorial [5,6]-homofullerene C70(CF2)

Victor A Brotsman; Natalia S Lukonina; Nikita A Malkin; Alexey V Rybalchenko; Nikita M Belov; Alexey A Goryunkov

doi:10.1039/d2cp01922a

Difluoromethylenation of fullerene C₇₀ provides isomeric diversity and availability of equatorial [5,6]-homofullerene C₇₀(CF₂)

Phys Chem Chem Phys. 2022 Jul 13;24(27):16816-16826. doi: 10.1039/d2cp01922a.

Authors

Victor A Brotsman¹, Natalia S Lukonina¹, Nikita A Malkin¹, Alexey V Rybalchenko¹, Nikita M Belov¹, Alexey A Goryunkov¹

Affiliation

¹ Chemistry Department, Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow, Russia. aag@thermo.chem.msu.ru.

PMID: 35786724
DOI: 10.1039/d2cp01922a

Abstract

We report synthesis, isolation, and spectroscopic characterization of the novel [5,6]-open C₇₀(CF₂) isomer III along with the already known [6,6]-closed and [6,6]-open C₇₀(CF₂) isomers I and II. The compounds were obtained in a ratio of I : II : III = 4 : 6 : 1 by means of thermal treatment of C₇₀ fullerene with sodium chlorodifluoroacetate. This product composition is explained with the use of quantum chemical calculations that identify the reaction pathway as a two-stage nucleophilic cyclopropanation rather than the previously postulated carbene addition. We further report the first cyclic voltametric studies for the whole set of isomers of C₇₀(CF₂). Together with the DFT data, they demonstrate that the LUMO is stabilized in both isomer II ([6,6]-open) and III ([5,6]-open) by 0.1 eV with respect to the pristine C₇₀, and isomer III has the lowest reorganization energy of all.