Hochmolekulares Polypropylen durch maßgeschneiderte Zirconocenkatalysatoren

Ethylene oligomerization catalyzed with dichlorobis‐(β‐diketonato)zirconium/organoaluminium chloride systems

“…Zr(fod),Cl, (1 d): to a suspension of anhydrous zirconium(1V) chloride (1.64 g, 7.04mmol) in benzene (30 mL) was added dropwise a benzene (10 mL) solution of a) Systematic IUPAC nomenclature: 2,4-pentanedione (Hacac); 1 , 1 , 1 -trifluoro-2,4-pentanedione (Htfa); l,l,l-trifluoro-5,5-dimethyl-2,4-hexanedione (Hpta); 6,6,7,7,8,8,8heptafluoro-2,2-dimethyl-3,5-octanedione (Hfod). heptafluorobutyrylpivaloylmethane (4.17 g, 14.1 mmol).…”

Racemic Dichloro{(R,R)-3,3'-(dimethylsilanediyl)bis[(1,2,3,3a,7a-η)-4,5,6,7-tetrahydro-1-indenyl]}zirconium

“…The Zr TM ion is r/5-bonded to the two siliconbridged tetrahydroindenyl ligands and a-bonded to two C1 ligands, adopting the familiar pseudotetrahedral 'ansa-metallocene' configuration (Smith, Von Seyerl, Huttner & Brintzinger, 1979). The title compound is, in all essential features, isostructural with its non-hydrogenated (Spaleck et al, 1992) congener (Table 3). The geometry around the Zr atom is comparable to that of similar silicon-bridged metallocenes (Burger, Hortmann, Diebold & Brintzinger, 1991;Stehling et al, 1994;Luttikhedde, Leino, N~isman, Ahlgrrn & Pakkanen, 1995).…”

“…The catalytic properties of both the title complex ( Fig. 1) and the non-hydrogenated congener have been discussed (Spaleck et al, 1992). The polar activation in copolymerization of propylene and a phenolic polymer stabilizer when using the hydrogenated congener and MAO was recently reported (Wilrn & N~isman, 1994).…”

Ultra‐Rigid Metallocenes for Highly Iso‐ and Regiospecific Polymerization of Propene: The Search for the Perfect Polypropylene Helix

“…Due to the fact that the amount of regioerrors is similar for entries 4, 5 and 6-8, the change in T m is only influenced by the mmmm-pentad concentration. A nearly linear increase of T m can be seen in the case of the lower tacticities (entries [6][7][8]. Going further to lower poly-merization temperatures (entries 5 and 6) the amount of the mmmm-pentad is increased in the same way as before, while the T m increases more significantly.…”

“…The 2-and 4-positions on the indenyl moiety have proven to be crucial ( Table 1). [8][9][10] The 2-methyl group is known to increase molecular weight due to the inhibition of the bimolecular chain release by b-hydride transfer to the next coordinated mono-mer. Additionally substitution in 4-position increases molecular weight and isotacticity.…”