Molecular geometries, electronic properties, and vibrational spectroscopic studies of endohedral metallofullerenes TM@C_(24) and TM@C_(24)H_(12) (TM = Cr, Mo, and W)

摘要

Molecular geometries, electronic properties, and vibrational spectroscopies of TM@C_(24) and TM@C_(24)H_(12) (TM = Cr, Mo, and W) in their different spin configurations have been systematically investigated with the hybrid DFT-(U)B3PW91 functional. The results show that the TM atoms bind over the pentagon ring inside C_(24) cage, and they move gradually toward the center of C_(24) cage along with the increasing atomic radii. The most stable Mo@C_(24)H_(12) and W@C_(24)H_(12) are in their spin-triplet states. The analyses of dissociation energy and energy gap reveal that TM@C_(24) (TM = Cr, Mo, and W) and Cr@C_(24)H_(12) are not only thermodynamically stable, but also considerably stable kinetically. Meanwhile, natural population analyses tell us that the two cages act as electron acceptors, and the transferred charge from the W atom to C_(24) cage is the largest in the endohedral metallofullerenes. Additionally, the vibrational frequencies and active infrared intensities may be used as evidence to characterize these unknown species.