Of all polymerization methods, catalytic polymerization offers the broadest scope of microstructure control. Stereoregularity, comonomer incorporation and sequences, molecular weights, and molecular weight distributions can be controlled by the catalyst structure. Polyolefins are produced on a vast scale of nearly 100 million tons annually, predominantly by catalytic polymerization. High-densit...

A series of Cr(III) complexes based on quinoline-cyclopentadienyl ligands with additional hemilabile side arms were prepared and used as single-site catalyst precursors for ethylene polymerization. The additional donor functions interact with the metal centers only after activation with the co-catalyst. Evidence for this comes from DFT-calculations and from the differing behavior of the complex...

The stereospecific polymerization of conjugated dienes began in 1954 with the first catalysts obtained by combining TiCl4 or TiCl3 with aluminum-alkyls, i.e. the catalytic systems previously employed for ethylene and propylene polymerizations. Subsequently, many other catalytic systems were obtained and examined by a combination of transition metal or lanthanide compounds with appropriate alkyl...

A number of half-zirconocene anilide complexes of the type Cp*ZrCl(2)[N(2,6-R(1)(2)C(6)H(3))R(2)] [R(1) = (i)Pr (1, 3), Me (2); R(2) = Me (1, 2), Bn (3)] and Cp*ZrCl[N(2,6-Me(2)C(6)H(3))Me](2) (4) (Cp* = pentamethylcyclopentadienyl) were synthesized from the reactions of Cp*ZrCl(3) with the lithium salts of the corresponding anilide in diethyl ether at room temperature. All new zirconium comple...

a fi zr-based catalyst of bis[n-(3,5-dicumylsalicylidene)-2′,6′­diisopropylanilinato]zirconium(iv) dichloride was prepared and used for polymerization of ethylene. the effects of reaction conditions on the polymerization were examined in detail. the increase in ethylene pressure and rise in polymerization temperature up to 35 oc were favorable for catalyst/mao to raise the catalytic activity as...

Cyclopentadienyl-titanium complexes containing –OC6H4X ligands (X = Cl, CH3) activated with methylaluminoxane (MAO) were used in the homo-polymerization of ethylene, propylene, 1-butene, 1-pentene, 1-butene, and 1-hexene, and also in copolymerization of ethylene with the α-olefins mentioned. The -X substituents exhibit different electron donor-acceptor properties, which is described by Hammett’...

The replacement of one of the two C5Me5 ligands in the samarocene(II) complex (C5Me5)2Sm(thf)2 with a monodentate anionic ligand such as OAr, SAr, NR1R2, or CH(SiMe3)2 gave a unique catalytic system, which can not only polymerize styrene and ethylene, but also copolymerize them into block styrene–ethylene copolymers under the presence of both monomers. On the other hand, the addition of an appr...

A series of oxovanadium(V) complexes containing amine pyridine(s) phenolate ligands [ONN] (2a-f) have been synthesized in high yields (68-83%) by reacting VO(O(n)Pr)3 with 1.0 equiv. of the ligands in CH2Cl2. These complexes were characterized by (1)H, (13)C and (51)V NMR spectroscopy and elemental analysis. X-ray structural analysis for 2a, 2c and 2d revealed that these complexes adopt a six-c...

Rare earth metal bis(alkyl) complexes attached by fluorenyl modified N-heterocyclic carbene (NHC) (Flu-NHC)Ln(CH(2)SiMe(3))(2) (Flu-NHC = (C(13)H(8)CH(2)CH(2)(NCHCCHN)C(6)H(2)Me(3)-2,4,6); Ln = Sc (2a); Y (2b); Ho (2c); Lu (2d)), ((tBu)Flu-NHC)Ln(CH(2)SiMe(3))(2) ((tBu)Flu-NHC = 2,7-(t)Bu(2)C(13)H(6)CH(2)CH(2)(NCHCCHN)C(6)H(2)Me(3)-2,4,6; Ln = Sc (1a); Lu (1d)) and attached by indenyl modified ...