Electronic states of neutral and cationic bis(benzene) titanium and vanadium sandwich complexes studied by pulsed field ionization electron spectroscopy

Ti– and V–bz2 (bz=C6H6) sandwich complexes have been prepared in a laser-ablation cluster beam source and studied by pulsed field ionization–zero electron kinetic energy photoelectron spectroscopy and theoretical calculations. The ground electronic states of the neutral Ti– and V–bz2 complexes are determined to be A1g1 and A1g2, and their ionization energies are measured to be 5.732±0.001 and 5.784±0.002eV, respectively. These neutral complexes have η6 binding and are in an eclipsed D6h configuration with flat benzene rings. Ionization of the A1g1 and A1g2 neutral states of Ti– and V–bz2 yields the B1g2 and B1g3 ion states, respectively, in a D2h point group with slightly puckered benzene rings. In addition, the binding and structures of these two complexes are compared with other first-row transition metal bis(benzene) sandwiches.