Photodissociation of M+(benzene)x complexes (MÂ =Â Ti, V, Ni) at 355Â nm

Transition metal cation-benzene complexes of the form M+(C6H6)1-7 (M = Ti, V, Ni) are produced in a laser vaporization pulsed nozzle cluster source. The clusters are mass selected and photodissociated using the third harmonic of a Nd:YAG laser (355 nm). Ti+(C6H6) fragments via ligand decomposition to produce Ti+C4H2, Ti+C2H2, and Ti+. V+(C6H6) fragments by ligand elimination of neutral benzene to give V+ as the primary fragment. Ni+(C6H6) fragments via both ligand elimination and a photoinduced charge transfer pathway to give benzene cation. Complexes with two benzene ligands fragment by the loss of a single neutral benzene to leave M+(C6H6) as the fragment. Clusters with more than two benzenes fragment directly down to M+(C6H6)2 with a small amount of M+(C6H6) for M = Ti and Ni. This indicates that a stable sandwich core is established at M+(C6H6)2 that is solvated by subsequent benzenes. There is no evidence for three-fold coordination in any of these complexes.