Ternary metallocene catalyst systems based on metallocene dichlorides and AlBu3i/[PhNMe2H][B(C6F5)4]

Modification of Methylaluminoxane‐Activated ansa‐Zirconocene Catalysts with Triisobutylaluminum—Transformations of Reactive Cations Studied by NMR Spectroscopy

“…[31][32][33] In addition to the interconversion between different type III species, by exchange of terminal methyl groups against isobutyl groups, a significant reduction of their total concentrations at elevated [AliBu 3 ] add /[Zr] ratios is apparent from Figure 2. The appearance of new ligand signals (denoted as I H 2 in Figure 2) and of the signals of isobutylene at d = 1.59 and 4.73 ppm, as well as previous observations on related reaction systems, [17,34,35] suggest that the isobutylated adducts III iBuMe and III iBu 2 are partly converted to some hydride species. Results of more direct studies on these hydride species, in reaction systems containing [Me 2 SiA C H T U N G T R E N N U N G (ind) 2 ZrCl 2 ], MAO and diisobutylaluminum hydride, will be reported in a separate communication.…”

“…[10][11][12][13][14][15] A primary task would be to clarify the way in which species of this type react with added AliBu 3 . In continuation of previous inquiries, [16][17][18][19][20] we have investigated in detail, by use of 1 H and 13 C NMR spectroscopic methods, which transformations these cationic zirconocene complexes undergo upon addition of alkylaluminum compounds to MAO-activated catalyst systems derived primarily from rac-[Me 2 Si-A C H T U N G T R E N N U N G (ind) 2 ZrCl 2 ] (1) (ind: indenyl).…”

Formation and structures of cationic zirconium complexes in ternary systems (X=Cl, Me)

“…Apparently, one of the diastereomers strictly prevails in our case. On the basis of the spectroscopic and literature data [20], a possible route for the formation of IV was derived (Scheme 2).…”

“…Recently, Gö tz and co-workers have reported an NMR investigation of the products of successive reaction of Cp 2 ZrCl 2 and Ph 2 C(Cp)(Flu)ZrCl 2 with Al i Bu 3 and [PhNMe 2 H][B(C 6 F 5 ) 4 ] at elevated temperature (60°C) [20]. They found the surprising formation of hydrido-bridged Zr-Al binuclear species, although some intermediates could only be tentatively identified.…”

Metallocene‐catalyzed olefin polymerization using magnesium chloride‐supported borate activators

“…16 Zirconocene dialkyls are typically activated using [Ph 3 18 Borate activators can also be used in combination with metallocene dichlorides, if a third component such as triisobutylaluminum able to alkylate the metallocene is present. 19,20 Tethering of a borate activator to magnesium chloride, involving activators containing a Lewis base functionality able to coordinate to the Lewis acidic support, has recently been described. 21 3 , with the aim of tethering the borate to the support material via reaction of a Si-O-Al-R moiety with the active hydrogen of the borate.…”