beside ziegler-natta and phillips catalysts the development of methylaluminoxane (mao) as cocatalyst incombination with metallocenes or other transition metal complexes for the polymerization of olefins haswidely increased the possibilities in controlling the polymer composition, polymer structure, tacticity and special properties with high precision. these catalysts allow the synthesis of isot...

Variable temperature spectroscopic, kinetic, and chemical studies were performed on a soluble CrIIICl3(PNP) (PNP = bis(diarylphosphino)alkylamine) ethylene trimerization precatalyst to map out its methylaluminoxane (MAO) activation sequence. These studies indicate that treatment of CrIIICl3(PNP) with MAO leads to first replacement of chlorides with alkyl groups, followed by alkyl abstraction, a...

The propensity of a half-sandwich (η5-tetramethylcyclopentadienyl) dimethylsilylamido Ti-based catalyst bearing an auxiliary diethylboryl-protected pyridyl moiety (Ti-8), activated by methylaluminoxane (MAO) to homopolymerize α-olefins such as ethylene, 1-hexene and styrene as well as to copolymerize styrene with 1,3-cyclohexadiene is described. The reactivity of Ti-8 was investigated in compar...

The dinuclear complex Cp*2Os2Br4 (Cp* ) pentamethylcyclopentadienyl) and related mono(pentamethylcyclopentadienyl)osmium compounds are catalysts for the ring-opening metathesis polymerization (ROMP) of norbornene. The most active catalyst prepared to date is made by treatment of Cp*2Os2Br4 with methylaluminoxane. This catalyst polymerizes norbornene with yields up to 167 kg of polymer per mol o...

A set of new chromium(III) [Cr(III)] complexes based on the tridentate ligand HC(Pz)2Py (Pz = pyrazole; Py = pyridine) and its derivatives were prepared, characterized, and evaluated for ethylene polymerization/oligomerization. X-ray single-crystal analyses of the Cr(III) complexes showed tridentate coordination on the fac-octahedral Cr sphere. Upon activation with methylaluminoxane (MAO), the ...