Reaction of the amido-bridged zirconium complex (CpSiMe(2)NSiMe(2)Cp)ZrCH(3) (1) (Cp = C(5)H(4)) with half an equivalent of B(C(6)F(5))(3) or Ph(3)CB(C(6)F(5))(4) afforded the binuclear zirconium complexes [(CpSiMe(2)NSiMe(2)Cp)Zr)(2)(mu-CH(3))][RB(C(6)F(5))(3)] (2a, R = CH(3), 2b, R = C(6)F(5)) with a methyl group as the bridge between the two zirconium atoms. In the presence of one equivalent...

A commercial SiO2 modified by the addition of a TiO2 layer on its surface and pore walls offers support for metallocene-based ethylene polymerization catalysts with 35% improved catalytic activity. The effect such modification catalyst particle fragmentation during reactions were assessed. This was performed exposing internal cross-section several Ti/SiO2-based metallocene particles, polymerize...

INTRODUCTION Emulsion polymerization yielding polymer latexes, is carried out on a vast scale. The use of water as a dispersion medium offers a unique combination of features, such as effective heat transfer, effective stabilization of polymer particles by surfactants, and environmental friendliness. By contrast to polymerization in solution or in the bulk, in emulsion polymerization a large po...

Poly(ethylene glycol) (PEG)-armed Ru(II)-bearing microgel-core star polymer catalysts were used for the transfer hydrogenation of ketones. The star catalysts (Ru(II)-PEG Star) were one-pot synthesized by ruthenium-catalyzed living radical polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and a sequential linking reaction with ethylene glycol dimethacrylate (1) and diphen...

We report here the first application of the computationally efficient metadynamics approach for analyzing single-site olefin polymerization mechanisms. The mechanism of group 4 metallocenium catalysis for ethylene homopolymerization is investigated by modeling the ethylene insertion step at the cationic (η(5)-C5H5)Zr(CH3)2(+) center using molecular dynamics simulations within the Density Functi...

We report the synthesis of two novel binuclear Pd–diimine catalysts and their unique behaviors in initiating “living” polymerization of ethylene and 1-hexene. These two binuclear catalysts, [(NˆN)Pd(CH2)3C(O)O(CH2)mO(O)C(CH2)3Pd(NˆN)](SbF6)2 (3a: m = 4, 3b: m = 6) (NˆN≡ArN=C(Me)–(Me)C=NAr, Ar≡2,6–(iPr)2C6H3), were synthesized by simply reacting [(NˆN)Pd(CH3)(N≡CMe)]SbF6 (1) with diacrylates, 1,...

Ab initio SCF-LCAO-MO all-electron calculations have been performed for the catalyzed reaction, related to the Ziegler-Natta polymerization process TiCl.·Al(CH3)3+C2H. -+TiCl •. Al(CH3h·C3H7. The energy of the Ti-Al--ethylene complex during the reaction pathway is associated to the following processes: First, the ethylene coordinates to the catalyst complex and subsequently it reacts with the m...