INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
An Electron Rich {RuNO}6 Complex: trans-[Ru(DMAP]4(NO)(OH)]2+ - Structure and Reactivity
Autor/es:
N.OSA CODESIDO, A.G.DE CANDIA, T. WEYHERMüLLER, J.A. OLABE, L.D. SLEP
Revista:
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
Editorial:
WILEY-V C H VERLAG GMBH
Referencias:
Lugar: Weinheim; Año: 2012 p. 4301 - 4301
ISSN:
1434-1948
Resumen:
Abstract The pseudo-octahedral nitrosyl species trans-[Ru(DMAP)4(NO)(OH)]2+ [12+, DMAP = 4-(dimethylamino)pyridine] was prepared by the reaction between [Ru(DMAP)5(H2O)]2+ and NaNO2 under mild conditions (room temperature, pH = 6?8), and precipitated with NaBF4 or NaPF6. Single-crystal X-ray diffraction data of 1(BF4)2·2H2O point to a {RuNO}6 electronic configuration of the cation, although there is a significant deviation from the expected linear arrangement of the RuNO moiety (Ru?N?O angle: 169.3°). The remarkably low wavenumber of the NO stretching band (íNO) of 1832 cm?1 in the solid state corresponds to an electron-rich ligand environment with strong backbonding interactions between dð metal orbitals and ð*NO orbitals of the (formal) NO+ (nitrosonium) ligand. Consistently, the complex acts as a poor electrophile: it is extremely unreactive toward OH? and toward the stronger nucleophile cysteine. Cyclic voltammetry (CV) experiments show three reduction processes in acetonitrile. The first one at ?0.50 V [vs. Ag/AgCl, KCl(s)] is reversible on the CV time scale. Spectroelectrochemical experiments (IR and UV/Vis) suggest that the reduced complex has a {RuNO}7 configuration. The íNO wavenumber of 1603 cm?1 agrees with a reduction mostly centered at the nitrosyl ligand. This species appears to be inert toward substitution in the coordination sphere, and the original {RuNO}6 ion can be quantitatively recovered upon oxidation. In contrast, further reduction of this species is completely irreversible, even on the CV timescale, which is probably due to the lability of the presumably formed nitroxyl (NO?) ligand.