Zwitterionic Ammoniumalkenyl Ligands in Metal Cluster Complexes. Synthesis, Structures, and Transformations of Zwitterionic Trimethylammoniumalkenyl Ligands in Hexaruthenium Carbido Carbonyl Complexes.

Ru(μ-C)(CO), , has been shown to react with CH when activated by MeNO to yield the complexes RuC(CO)(μ-η-CHNMe), , and RuC(CO)(μ-η-CHNMe), , containing a bridging 2-trimethylammoniumethenyl (CHNMe) ligand and a triply bridging 4-trimethylammoniumbutadienyl (CHNMe) ligand, respectively. Complexes and are formally zwitterionic by virtue of the positive charge on the nitrogen atom and a negative charge that must be assigned formally to the Ru cluster. Compound added CO at room temperature to yield the compound RuC(CO)(η--CHNMe), , that contains a terminally coordinated zwitterionic 2-trimethylammoniumethenyl ligand.

Selective Activation of CH Bonds in Polar Vinyl Olefins and Coupling of Ethylene to the Activated Carbon Atoms in Pentaruthenium Complexes.

Ru(μ-C)(CO), 1, has been found to activate CH bonds in the vinyl group of polar vinyl olefins, methyl acrylate (MA), and vinyl acetate (VAc), through a cluster opening process to yield the complexes Ru(μ-C)(CO)[η-O═C(OMe)CH═CH](μ-H), 2, and Ru(μ-C)(CO)[η-(MeCO)C═CH](μ-H), 4, respectively. The site of CH activation is dependent on the olefin substituent. In 2, the site of CH activation is the β-carbon atom of the vinyl group, while in 4 the CH activation has occurred exclusively at the α-carbon atom of the vinyl group.