NEAR-IR ABSORPTION-SPECTRA FOR THE C-70 FULLERENE ANIONS

C70, like C60, can exist in a number of oxidation states including C70(1-), C70(2-), C70(3-), and C70(4-). We have discovered unique visible and near-IR absorption transitions which appear upon reduction of C70. These transitions are observed upon one-, two-, three-, and four-electron electrochemical reductions of C70. In contrast to C60, however, the electronic properties of C70 are less well understood. In particular, previous theoretical studies of C70(1-) failed to predict the existence of the near-IR transition we observe in the spectrum of C70(1-). In this paper, in addition to presenting the heretofore unreported spectra of the various C70 anions, we attempt a first-order explanation of the energies and intensities of the various spectral absorptions; this explanation is based on the published molecular orbital diagram for neutral C70 and a structural distortion that we suggest occurs upon reduction of C70.