A series of dissymmetric dinuclear complexes were synthesized, as dual site catalysts in ethylene polymerization, by coupling the allylated a-diimine complexes of the metals Ti, Zr, V, Ni and Pd with the ansa-zirconocene complex [C5H4-SiH(Me)-C5H4]ZrCl2 possessing a hydride silane moiety. The different stages of syntheses included the formation of bis(cyclopentadienide)methyl silane which was u...

An efficient and general method for the synthesis of reduced polypropionates has been developed through the application of asymmetric carboalumination of alkenes catalyzed by dichlorobis(1-neomenthylindenyl)zirconium [(NMI)(2)ZrCl(2)]. In this investigation, attention has been focused on those reduced polypropionates that are alpha-monoheterofunctional and either omega-ethyl or omega-n-propyl. ...

A series of novel titanium complexes bearing tridentate β-enaminoketonato chelating ligands of type, [R(2)NC(CF(3))C(H)CR(1)O]TiCl(3) (2a: R(1) = Ph, R(2) = -C(6)H(4)OMe(o); 2b: R(1) = Ph, R(2) = -C(9)H(6)N; 2c: R(1) = Ph, R(2) = -C(6)H(4)SMe(o); 2d: R(1) = Ph, R(2) = -C(6)H(4)SPh(o); 2e: R(1) = (t)Bu, R(2) = -C(6)H(4)SPh(o)) and [R(2)NC(R(1))C(H)C(CF(3))O]TiCl(3) (2f: R(1) = Ph, R(2) = -C(6)H(...

Four examples of para-nitro substituted 2-(arylimino)pyridine-nickel(II) bromide complexes general formula, [2-{(2,6-R-4-NO2C6H2)N=CMe}C5H4N]NiBr2, but differentiable by the steric/electronic properties displayed ortho-groups [R = i-Pr (Ni1), Et (Ni2), CHPh2 (Ni3), CH(4-FPh)2 (Ni4)], have been prepared in good yield. For comparative purposes, meta-nitro complex, [2-{(2,6-i-Pr2-3-NO2-4-(4-FPh)2C...

Results are presented of ab initio studies at levels MP2(full)/6-31G* and MP2(full)/6-311G** of the hydrolysis of trimethylaluminum (TMA, 1) to dimethylaluminumhydroxide (DMAH, 2) and of the intramolecular 1,2-elimination of CH(4) from 2 itself to form methylaluminumoxide 3, from its dimeric aggregate 4 to form hydroxytrimethyldialuminoxane 5 and dimethylcyclodialuminoxane 6, and from its TMA a...

The first structurally characterized isobutyl-containing aluminoxane compound is presented. The Al10O6iBu16(mu-H)2 (I) cluster is produced from neat octakis-isobutyltetraluminoxane (Al4O2iBu8) at 80 degrees C in 6-8 h followed by slow crystallization. The crystal is triclinic (space group P1) with the molecule lying on an inversion center. This aluminoxane contains both nearly linear, 154(2) de...

In the presence of bidentate 1,n-bis-diphenylphosphinoalkane-CoCl2 complexes {Cl2Co[P P]} and Me3Al or methylaluminoxane, acyclic (E)-1,3-dienes react with ethylene (1 atmosphere) to give excellent yields of hydrovinylation products. The regioselectivity (1,4or 1,2-addition) and the alkene configuration (Eor Z-) of the resulting product depend on the nature of the ligand and temperature at whic...

Reaction of the ligand 2,4-tert-butyl-6-[(2-methylquinolin-8-ylimino)methyl]phenol (L(1)H) with [VOCl3] in the presence of triethylamine afforded the complex [VOCl2L(1)] (1), whereas use of [VO(OnPr)3] led to the isolation of [VO2L(1)] (2) or [VO2L(1)]·2/3MeCN (2·2/3MeCN). Reaction of 2-((2-(1H-benzo[d]imidazol-2-yl)quinolin-8-ylimino)methyl)-4,6-R(1),R(2)-phenols (R(1) = R(2) = (t)Bu; L(2)H), ...

In the presence of bidentate 1,n-bis-diphenylphosphinoalkane-CoCl2 complexes {Cl2Co[P~P]} and Me3Al or methylaluminoxane, acyclic (E)-1,3-dienes react with ethylene (1 atmosphere) to give excellent yields of hydrovinylation products. The regioselectivity (1,4- or 1,2-addition) and the alkene configuration (E- or Z-) of the resulting product depend on the nature of the ligand and temperature at ...

INTRODUCTION Polystyrene can be obtained in atactic (aPS), isotactic (iPS) or syndiotactic (sPS) form by a variety of catalytic systems1,2 and initiators. For instance, it is known that (pentamethylcyclopentadienyl)titanium derivatives activated by methylaluminoxane (MAO) afford a highly sPS, with %m (defined as meso diads content, calculated by 13C-nuclear magnetic resonance (NMR)) below the i...