Reactions of a Ru(II) Phenyl Complex with Substrates that Possess C−N or C−O Multiple Bonds: C−C Bond Formation, N−H Bond Cleavage, and Decarbonylation Reactions

The Ru(II) phenyl complex TpRu(CO)(NCMe)(Ph) (1) (Tp = hydridotris(pyrazolyl)borate) reacts with
carbodiimides to yield amidinate complexes that result from C−C bond formation between the phenyl
ligand and the carbodiimide carbon. Complex 1 and N-methylacetamide react to produce benzene and
the amidate complex TpRu(CO){(N,O-OC(Me)N(Me)} (4). The reaction of complex 1 with C⋮N(tBu)
yields TpRu(CO){C⋮N(tBu)}(Ph) (5), and heating a solution of PMe3 and 5 results in the observation
of an equilibrium with the product of isonitrile insertion TpRu(CO){C(Ph)NtBu}(PMe3) (6) (ΔH =
+9(1) kcal/mol and ΔS = +20(3) eu). The reaction of 1 with aromatic aldehydes at elevated temperatures
results in C−H activation and decarbonylation of the aldehyde to produce TpRu(CO)2(Ar) (Ar = phenyl
or p-tolyl) and free benzene. DFT calculations have been incorporated to study coordination and insertion
reactions of ethylene, methyleneimine, formaldehyde, HNCNH, and C⋮NH into the Ru−Ph bond of
the model fragment (Tab)Ru(CO)(Ph) (Tab = tris(azo)borate). In addition, the energetics of Ru-mediated
decarbonylation of formaldehyde have been calculated.