Di-µ-chlorido-bis-[bis-(η-cyclo-octene)iridium(I)].

The title complex, [Ir(2)(µ-Cl)(2)(C(8)H(14))(4)], has a dinuclear structure with bridging Cl atoms, a hinge angle of 179.44 (7)° between the two IrCl(2) planes, and an Ir⋯Ir distance of 3.7254 (3) Å. Regarding the coordinating C=C bonds as occupying a single coordination site each, the geometry around each Ir atom is square-planar.

Half-Metallocene Tantalum Complexes Bearing Methyl Methacrylate (MMA) and 1,4-Diaza-1,3-diene Ligands as MMA Polymerization Catalysts.

Activation with AlMe3 at low temperature converts half-metallocene complexes of tantalum with methyl methacrylate (MMA) and diazadiene ligands such as [Cp*Ta(η2 -Cy-DAD)(η4 -MMA)] (structure shown) into effective catalysts for the polymerization of MMA. Polymerization is complete after 10 min at -20°C and gives a poly(methyl methacrylate) of narrow polydispersity. Cp*=η5 -C5 H5 , Cy-DAD=1,4-dicyclohexyl-1,4-diaza-1,3-butadiene.

Facile Oxidative Addition of O-H Bonds of Methanol and Water to IrI Complexes Having Peraryldiphosphane Ligands.

A new piece in the puzzle. Hydrido(alkoxo) complexes of late transition metals have often been postulated as intermediates or transition states in the catalytic hydrogenation of carbonyl compounds and catalytic hydrogen transfer reactions. Here the facile oxidative addition of the O-H bonds of alcohol and water to iridium(I) complexes of peraryldiphosphanes [Eq. (a)] is reported and the resulting complexes are described. R=H, Me.

A Novel C-C Single-Bond Formation Accompanying C-O Bond Cleavage by Use of a Ketone, an Alkylating Reagent, and a Low-Valent Vanadium Complex in the Presence of a Catalytic Amount of Molecular Oxygen.

A C-C single-bond-forming reaction from ketones with accompanying C-O bond cleavage mediated by a RMgBr or RLi-vanadium(II)-O(2) system has been accomplished. Different from conventional reductive coupling reactions of ketones such as the McMurry coupling, the present method forms a C-C single (instead of a double) bond and yields a product that contains components derived from the ketone and the alkylating reagent in a one-pot reaction. Collaboration of both a low-valent vanadium(II) species and a higher-valent vanadium species produced from vanadium(II) and a catalytic amount of O(2) effects the abstraction of the oxygen atom from a C-O bond.