Displacement of phenyl and styryl ligands by benzophenone imine and 2-vinylpyridine on ruthenium and osmium

The phenyl complexes MPhCl(CO)((PPr3)-Pr-i)(2) (M = Ru(3), Os (4)) have been prepared by reaction of MHCl(CO)((PPr3)-Pr-i)(2) (M = Ru (1), Os (2)) with HgPh2. In solution the phenyl ligand of these compounds rotates around the M-Ph bond. The activation parameters for the process are Delta H double dagger = 13.0 +/- 0.6 kcal.mol(-1) and Delta S double dagger = 1.5 +/- 1.3 cal.mol(-1).K-1 for 3 and Delta H double dagger = 11.7 (0.5 kcal.mol(-1) and Delta S double dagger = -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)((PPr3)-Pr-i)(2) (M = Ru (7), Os (8)) leads to equilibrium mixtures between the starting compounds and the six-coordinate derivatives MPhCl(NH=CPh2)(CO)((PPr3)-Pr-i)(2) (M = Ru (5): Delta H degrees = -8.6 +/- 0.4 kcal.mol(-1), Delta S degrees = -42.5 +/- 1.6 cal.mol(-1).K-1; M = Os (6): Delta H degrees = -9.1 +/- 0.8 kcal.mol(-1), Delta S degrees = -31.0 +/- 2.6 cal.mol(-1). K-1) and M{(E)-CH=CHPh}Cl(NH= CPh2)(CO)((PPr3)-Pr-i)(2) (M = Ru (9): Delta H degrees = -9.5 +/- 0.3 kcal.mol(-1), Delta S degrees = -39.4 +/- 1.1 cal.mol(-1).K-1; M = Os (10): Delta H degrees = -8.8 +/- 0.8 kcal.mol(-1), Delta S degrees = -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{C6H4C(Ph)=NH}Cl(CO)(PPr3)-Pr-i)(2) (M = Ru (11), Os (12)) and M(NC5H4-o-CH=CH)Cl(CO)((PPr3)-Pr-i)(2) (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 center dot center dot center dot H-N hydrogen bond (2.47 angstrom) between the NH hydrogen atom of the imine and the chloride ligand.