Geometries and stabilities of 3d-transition metal-cation benzene complexes, M+Bzn (M = Sc-Cu, n = 1, 2)

The geometries of the 3d-transition metal-cation benzene (Bz) half-sandwich (C6v), M+Bz (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu), and sandwich complexes, M+Bz2, in the respective staggered (D6d) and eclipsed (D6h) conformations are optimized using the B3LYP density functional in Gaussian 03. In both cases we find the respective dissociation energies (with respect to loss of one benzene molecule) to be approximately inversely proportional to the distance between the metal atom and the benzene ring(s) with the latter being only slightly deformed. For the half-sandwich complexes our results agree well with computed geometries and computed and measured dissociation energies from the literature. For the sandwich complexes, however, only measured dissociation energies are available, which turn out to deviate considerably from our results.