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

Ti- and V-bz(2) (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-bz(2) complexes are determined to be (1)A(1g) and (2)A(1g), and their ionization energies are measured to be 5.732 +/- 0.001 and 5.784 +/- 0.002 eV, respectively. These neutral complexes have eta(6) binding and are in an eclipsed D-6h configuration with flat benzene rings. Ionization of the (1)A(1g) and (2)A(1g) neutral states of Ti- and V-bz(2) yields the B-2(1g) and B-3(1g) ion states, respectively, in a D-2h 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. (c) 2007 American Institute of Physics.