Fullerene Anions of Different Sizes and Shapes:  A ¹³C NMR and Density-Functional Study

A combined experimental and theoretical study was conducted on numerous higher fullerene anions with different sizes and shapes, C₇₆-D₂, C₇₈-C_2v, C₇₈-D₃, C₈₄-D₂, and C₈₄-D_2d. The corresponding fullerenes were reduced by lithium metal to diamagnetic multiply charged anions. The centers of gravity of the ¹³C NMR spectra of all the multiply charged anions were deshielded, relative to those of the neutral fullerenes. The results of density functional (DFT) computations of the ¹³C NMR spectra and the molecular orbitals (MOs) of possible polyanion reduction products suggest that hexaanions were the species formed.