Crystallographic Structure Determination of Both [5,6]- and [6,6]-Isomers of Lithium-Ion-Containing Diphenylmethanofullerene
2017-05-10T00:00:00Z (GMT) by
Organic functionalization of lithium-ion-containing fullerene, Li<sup>+</sup>@C<sub>60</sub>, was performed by using diphenyl(diazo)methane as a stable, readily available diazo compound to obtain lithium-ion-containing [5,6]- and [6,6]-diphenylmethanofullerenes, Li<sup>+</sup>@C<sub>61</sub>Ph<sub>2</sub>. The bis(trifluoromethanesulfonyl)imide (TFSI) salts of [5,6]- and [6,6]-Li<sup>+</sup>@C<sub>61</sub>Ph<sub>2</sub> were successfully separated by using a cation exchange column with eluent containing LiTFSI. Improved separation protocol and high crystallinity of ionic components in less polar solvents enabled separate crystallization of each isomer. Both [5,6]-open and [6,6]-closed structures of Li<sup>+</sup>@C<sub>61</sub>Ph<sub>2</sub> were determined by synchrotron radiation X-ray crystallography. Elucidating the [5,6]-open methanofullerene (fulleroid) structure will contribute to materials research on fulleroids.