Auf der Suche nach einer neuen Generation von Katalysatoren zur Olefinpolymerisation: „Leben” jenseits der Metallocene

Abstract

Auch Komplexe später Übergangsmetalle sind aktive und selektive Katalysatoren für die Polymerisation von α‐Olefinen. Die Entdeckung einer Klasse hochaktiver Eisenkatalysatoren 1 beleuchtet, angesichts der Tatsache, daß Eisen auf diesem Gebiet bis dahin völlig bedeutungslos war, die Möglichkeiten zur Entdeckung neuer Katalysatoren. Entdeckungen wie diese lösten in den letzten Jahren sowohl in Universitäts‐ als auch in Industrielaboratorien eine intensive Suche nach neuen Katalysatoren aus. R1 = H, Me; R2 = Me, iPr; R3 = H, Me, iPr; R4 = H, Me; X = Halogen.

The (butadiene)zirconocene route to active homogeneous olefin polymerization catalysts

“…A third structural betaine type was experimentally detected when (g 4 -butadiene)bis(pentamethylcyclopentadienyl) zirconium (25) was treated with B(C 6 F 5 ) 3 . The resulting addition product (26) showed an unusual very distorted r,p-allyl-type structural subunit, marking some point on the pathway along the conversion from a p-allyl to a purely r-allyl structural type [18] (cf. Scheme 9).…”

“…Chelate bis(imine) complexes of a variety of metals from the right side of the periodic table have become quite important in homogeneous Ziegler-Natta catalysis [26]. Addition of B(C 6 F 5 ) 3 to the bis(imine)nickel(butadiene) complexes 51 [27] initially gave the cisoid zwitterionic p-allyl complexes 52.…”

Transition metal-based polymer chemistry: a critical micro-review

“…It would certainly exceed by far the scope of this article if one attempted to give a comprehensive review on group IV-based polyole n chemistry. Fortunately, some excellent reviews on this topic, including carbocationic alkene polymerization [28], have been published quite recently and will serve as a reference for comprehensive reading [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. Nevertheless, a few aspects of this chemistry that certainly deserve to be discussed will be mentioned.…”

“…The most outstanding feature of these systems is the fact that polar monomers such as methacrylates can at least be copolymerized, due to the reduced oxophilicity of these systems. Numerous comprehensive reviews have already paid tribute to the enormous signi cance of this comparably young area of chemistry [ 32,122,123]. These initiators usually yield high-molecular-weight, highly branched amorphous PE.…”

Parallel Synthesis and Testing of Catalysts for the Polymerization of Ethylene

“…[1] Newcomers with regard to their potential application in industrial processes are the so called late transition metal catalysts incorporating central metals like iron, nickel or cobalt in complexes typically bearing nitrogen-containing ligands. [2][3][4] Subtle ligand variations, the metal center and the type and amount of the activator all have more or less pronounced effects on the catalytic activity and selectivity. A large number of catalyst formulations must therefore be screened in order to find the best entity for a target application.…”