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('Bu)}(Ph) (5), and heating a solution of PMe 3 and 5 results in the observation of an equilibrium with the product of isonitrile insertion TpRu(CO){C(Ph)=N tBu}(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. © 2006 American Chemical Society y.

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