Displacement of Phenyl and Styryl Ligands by Benzophenone Imine and 2-Vinylpyridine on Ruthenium and Osmium

The phenyl complexes MPhCl(CO)(P i Pr 3 ) 2 (M = Ru ( 3 ), Os ( 4 )) have been prepared by reaction of MHCl(CO)(P i Pr 3 ) 2 (M = Ru ( 1 ), Os ( 2 )) with HgPh 2 . In solution the phenyl ligand of these compounds rotates around the M−Ph bond. The activation parameters for the process are Δ H ⧧ = 13.0 ± 0.6 kcal·mol - 1 and Δ S ⧧ = 1.5 ± 1.3 cal·mol - 1 ·K - 1 for 3 and Δ H ⧧ = 11.7 ± 0.5 kcal·mol - 1 and Δ S ⧧ = −5.4 ± 1.2 cal·mol - 1 ·K - 1 for 4 . The addition of benzophenone imine to dichloromethane solutions of 3 and 4 and the related styryl complexes M{( E )-CH CHPh}Cl(CO)(P i Pr 3 ) 2 (M = Ru ( 7 ), Os ( 8 )) leads to equilibrium mixtures between the starting compounds and the six-coordinate derivatives MPhCl(NH CPh 2 )(CO)(P i Pr 3 ) 2 (M = Ru ( 5 ): Δ H ° = −8.6 ± 0.4 kcal·mol - 1, Δ S ° = −42.5 ± 1.6 cal·mol - 1 ·K - 1; M = Os ( 6 ): Δ H ° = −9.1 ± 0.8 kcal·mol - 1, Δ S ° = −31.0 ± 2.6 cal·mol - 1 ·K - 1 ) and M{( E )-CH CHPh}Cl(NH CPh 2 )(CO)(P i Pr 3 ) 2 (M = Ru ( 9 ): Δ H ° = −9.5 ± 0.3 kcal·mol - 1, Δ S ° = −39.4 ± 1.1 cal·mol - 1 ·K - 1; M = Os ( 10 ): Δ H ° = −8.8 ± 0.8 kcal·mol - 1, Δ S ° = −27.3 ± 2.6 cal·mol - 1 ·K - 1 ). In toluene under reflux complexes 3, 4, 7, and 8 react with benzophenone imine and 2-vinylpyridine to afford the metalated derivatives (M = Ru ( 11 ), Os ( 12 )) and (M = Ru ( 13 ), Os ( 14 )), releasing benzene and styrene. Complexes 9, 12, and 13 have been characterized by X-ray diffraction analysis. The structure of 9 shows a Cl···H−N hydrogen bond (2.47 Å) between the NH hydrogen atom of the imine and the chloride ligand.