Synthesis, Characterization, and Reactions of Ruthenium Phenanthroline Complexes Bearing C₁ Ligands:  Formyl, Metallocarboxylate, and CO₂-Bridged Complexes

A new formyl complex, cis-Ru(phen)2(CO)(CHO)(PF6) (8), has been characterized, and some of its reactions have been compared with those of its bipyridyl analogue. Reactions of 8 with MeOH can be photoassisted and lead to a metalloester, 7; reaction rates are comparable to those of the bipyridyl analogue. Reactions of 8 in DME/H2O require O2 and can be photoassisted; the reactions lead to a μ2-η2-type CO2-bridged complex, 10. Reactions of 8 with water are slower than those of the bipyridyl analogue and allow observation of an intermediate metallocarboxylic acid, cis-Ru(phen)2(CO)(COOH)(PF6) (6), which has been structurally characterized. A related CO2-bridged complex, cis,cis-[Ru(phen)2(CO2)Ru(bpy)2(CO)](2PF6) (11), has also been prepared and structurally characterized; its spectral properties support the formulation of 10 and its bipyridyl analogue.