Preparation and Reactivity of Organometallic Complexes Bearing the Fragment "Cp^*Ru(CO)(PR~3)" (PR~3 = PMe^iPr~2, PEt~3): Dinuclear Complexes [{Cp^*Ru(CO)(PR~3)}~2(mu-Cl)]^+ Containing Two Chiral Centers, eta^2-Alkene, and Other Mononuclear Complexes