Phenoxy-amine

Fig. 15 Reaction scheme for the formation of a phenoxy-amine complex...

The production of highly isotactic PPs with Zr- and Hf-FI catalysts//-Bu3Al/ Ph3CB(C6F5)4 (phenoxy-amine complexes site-controlled polymerization with 1,2-insertion) is in sharp contrast to that of highly syndiotactic PPs with Ti-FI cata-lysts/MAO (phenoxy-imine complexes chain-end controlled polymerization with 2,1-insertion), which will be described later [64]. 

Fig. 24 Calculated structures of cationic phenoxy-amine complexes in the absence of 1-hexene (a), in the presence of 1-hexene (1-hexene-coordinated state) (b), and for transition state (c) (polymer chain model methyl group). Reproduced with permission from Saito et al. [27]. Copyright 2006, American Chemical Society...

Zirconium and hafnium dibenzyl complexes 258 incorporating tetradentate bis(bulky phenoxy) amines with an additionally heteroatom (N, O, or. Si-donor containing pendant sidearm are produced from the reaction of the... 

The remarkable effect of [Ph3C][B(C6F5)4]/Bu 3Al activation on the behavior of phenoxy-imine-based catalysts was ascribed to a reaction between Bu 3A1 and the imino functionality of the complexes. As already discussed in Section 4.09.5.3.2, it is commonly accepted that Bu 3A1 reduces the imino group to an amino group, thus converting a phenoxy-imine catalyst into a phenoxy-amine structure.1162... 

Catalysts based on the Hf pyridyl amine complexes 126-128 have been used for the preparation of ethylene/ propylene co-polymers as well as of ethylene/propylene/l-octene terpolymers. These co-polymers are characterized by having at least 60 wt% propylene units, Mw around 300000, and Mw/Mn in the range 2.0-2.4. The NMR analysis of these co-polymers showed that the propylene sequences are remarkably isotactic mm > 90%) and showed the presence of regioirregularly inserted propylene units(<0.5% mol). The most interesting property of catalysts based on 126-128 is their high thermal stability.1119 Using modifications of isospecific bis(phenoxy-amine)-based catalysts, such as complex 164, the controlled synthesis of iPP- /orjf-poly/E-co-P) diblock co-poly-mers has been achieved. This is a remarkable result since iPP and PE are both polymeric materials of extreme industrial relevance.1206... 

G. Ciancaleoni, N. Fraldi, P.H.M. Budzelaar, V. Busico, A. Macchioni, Strucmre and dynamics in solution of bis(phenoxy-amine)zirconium catalysts for olefin polymerization, Organometalhcs 30 (2011) 3096-3105. 

Tang Z, Gibson VC. 2007. rac-Lactide polymerization using aluminum complexes bearing tetradentate phenoxy-amine ligands. Europ Polym J 43 150-155. 

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