Probing the electronic structure of metallocarbohedrenes: M8C12 (M=Ti, V, Cr, Zr, Nb)

We report a systematic study of the electronic structure of the five metcars in the title using anion photoelectron spectroscopy, The electron affinities of the metcars are measured and are found to be metal dependent and increase from Ti8C12 to Cr8C12. The electronic structures of Zr8C12 and Nb8C12 are found to be similar to Ti8C12 and V8C12, respectively. All the spectra can be qualitatively interpreted by the molecular orbital schemes derived from a tetracapped tetrahedral M8C12 cluster. This work provides yet the most quantitative electronic and spectroscopic information about the metcars, as well as evidence supporting the tetrahedral structure for the metcars.