A new ligand for chromium-catalyzed polymerization of ethylene at room temperature. Crystal structures of the lignads and chromium complex

International audienc

Air-accelerated enantioselective hydrosilylation of ketones catalyzed by copper(I) fluoride-diphosphine complexes: Investigations of the effects of temperature and ligand structure

The fluorotris(triphenylphosphine)copper(I)-bis(methanol) complex-chiral diphosphine system catalyzes the hydrosilylation of several alkyl aryl ketones with moderate to excellent enantioselectivity. An oxygen acceleration effect was observed and led to a practical protocol with low catalyst loading. Optimizations of enantioselectivities (< 95%) and catalytic ratio (< 0.05 mol%) were obtained with bulky Ar-MeO-BIPHEP ligands

Activating supports with non-metallocene complexes

US Patent App. 11/989,736International audienc

Transition metal complexes supported on activating support

US Patent 8,426,539International audienc

Process for dispersing functional molecules on the surface of a support and support made by this process

The present invention discloses a method for sepg. tethered functional organo-chains, through their dilution with tethered nonfunctional organo-chains, in the presence of soluble molecular derivs. that are able to self-assemble and to interact with the functional organo-silane

Step-by-step uncoordination of the pyrazolyl rings of hydrotris(pyrazolyl)borate ligands in complexes of RhI and RhIII

Compounds of rhodium(I) and rhodium(III) that contain ancillary hydrotris(pyrazolyl)borate ligands (Tp′) react with monodentate and bidentate tertiary phosphanes in a step-wise manner, with incorporation of P-donor atoms and concomitant replacement of the Tp′ pyrazolyl rings. Accordingly, [Rh(κ3-TpMe2)(C2H4)(PMe 3)] (1b), converts initially into [Rh(κ2-TpMe2)-(PMe3)2] (3), and then into [Rh(κ1-TpMe2-(PMe3)3] (2) upon interaction with PMe3 at room temperature, in a process which can be readily reversed under appropriate experimental conditions. Full disengagement of the Tp′ ligand is feasible to give Tp′ salts of rhodium(I) complex cations, for example, [Rh(CO)(dppp)2]-[TpMe2,4-Cl] (5; dppp = Ph2P(CH2)3PPh2), or [Rh(dppp)2][TpMe2,4-Cl] (6). Bis(hydride) derivatives of rhodium(III) exhibit similar substitution chemistry, for instance, the neutral complex [Rh(Tp)-(H)2(PMe3)] reacts at 20°C with an excess of PMe3 to give [Rh(H)2-(PMe3)4][Tp] (9b). Single-crystal X-ray studies of 9b, conducted at 143 K, demonstrate the absence of bonding interactions between the [Rh(H)2(PMe3)4]+ and Tp ions, the closest Rh⋯N contact being at 4.627 Å. © Wiley-VCH Verlag GmbH, 2001.Peer Reviewe