Interaction of cyclohexyl isocyanate with oxoruthenium(V) 2-alkyl-2-hydroxybutyrates

Abstract

The interaction of the tetra-n-propylammonium salts of the oxoruthenium(V) anions [RuO{OCEt(R)C(O)O}₂]^–(R = Me or Et) with excess of cyclohexyl isocyanate in toluene or tetrahydrofuran forms salts of the amidoruthenium(IV) anions [Ru{NH(C₆H₁₁)}{OCEt(R)(O)O}₂]^–. Interaction of these amido species with dioxygen affords the corresponding paramagnetic imidoruthenium(V) anions. The crystal structure of the amido complex with R = Et has been determined by X-ray diffraction. The Ru atom is trigonal bipyramidally co-ordinated by two chelating OCEt₂C(O)O ligands and a terminal NH(C₆H₁₁) ligand; the carboxylate oxygen atoms are axial, while the deprotonated hydroxy groups and the amido ligand are equatorial. The Ru–N–C angle of 132.1° is consistent with an amido ligand; although the amido H atom could not be located crystallographically, its presence is clearly indicated by IR, ¹H NMR and X-ray photoelectron spectroscopy.