Unsaturated Carbene Transition-Metal Indenyl Complexes. 3. Synthesis and Characterization of (Alkynyl)-, (Vinylidene)-, and (Carbene)ruthenium Indenyl Complexes: X-ray Crystal Structure of Ru(:C:CMe2)(.eta.5-C9H7)(PPh3)2CF3SO3.cntdot.1/2CCH2Cl2 and EHMO Calculations