Highly Active and Isospecific Styrene Polymerization Catalyzed by Zirconium Complexes Bearing Aryl-substituted [OSSO]-Type Bis(phenolate) Ligands

Abstract

Abstract:[OSSO]-type dibenzyl zirconium(IV) complexes 9 and 10 possessing aryl substituents ortho to the phenoxide moieties (ortho substituents, phenyl and 2,6-dimethylphenyl (Dmp)) were synthesized and characterized. Upon activation with dMAO (dried methylaluminoxane), complex 9 was found to promote highly isospecific styrene polymerizations ([mm] = 97.5%-99%) with high molecular weights M w up to 181,000 g¨mmol´1. When the Dmp-substituted pre-catalyst 10/dMAO system was used, the highest activity, over 7700 g¨mmol(10)´1¨h´1, was recorded involving the formation of precisely isospecific polystyrenes of [mm] more than 99%.

Highly Efficient and 1,2-Regioselective Method for the Oligomerization of 1-Hexene Promoted by Zirconium Precatalysts with [OSSO]-Type Bis(phenolate) Ligands

“…Recently, our group reported several zirconium complexes that contain an [OSSO]-type bis­(phenolate) ligand based on a trans -1,2-cyclooctanediyl core. These complexes serve as precise polymerization catalysts for α-olefins and yield excellent isotactic poly­(α-olefin)­s. , Motivated by these results and the desire to further explore reactions catalyzed by [OSSO]-type complexes, we would like to report herein the high performance of dried-modified methylaluminoxane-activated (dMMAO) zirconium precatalysts 7 and 8 , which possess [OSSO]-type ancillary ligands with ortho , para -diphenylphenol or ortho -{2,6-dimethylphenyl (Dmp)}- para -methylphenol substituents, respectively, in the 1,2-regioselective oligomerization of 1-hexene using relatively low catalyst loadings …”

“…GC-MS charts were obtained with a Bruker SCION SQ 456-GC/MS system equipped with an InertCap Pure-WAX 30 m column. [OSSO]-type zirconium complexes ( 7 and 8 ) and dMMAO were prepared by the literature procedures.…”

Carbazolyl-Substituted [OSSO]-Type Zirconium(IV) Complex as a Precatalyst for the Oligomerization and Polymerization of α-Olefins

“…The relative integral ratio of these vinylidene signals suggested an oligomeric distribution as follow; 39% of dimer, 34% of trimer, and 27% of other oligomers. Increasing the amount of dMMAO to 150, 200, and 250 equivalents also resulted in the dominant production of vinylidene-ended oligomers including dimers of high contents in 56-62% ( Since dibenzyl zirconium(IV) complexes 1 and 2 featuring aryl-substituted [OSSO]-type ligands have already served as useful precatalysts for the isospecific polymerization of styrene [46], we next turned our attention to the polymerization of styrene employing Cbz-substituted precatalyst 4. The results are summarized in Table 2.…”

“…The combination of these complexes and activators could achieve the controlled isotactic polymerization of various α-olefins involving excellent activity. Recently, we have also preliminarily investigated the preparation of dibenzyl zirconium(IV) complexes (1 and 2) bearing [OSSO]-type bis(phenolate) ligands substituted with phenyl or 2,6-dimethylphenyl (Dmp) groups on the phenolate groups (Scheme 1) [46]. Upon activation with dMAO (dried methylaluminoxane), the dibenzyl complexes 1 and 2 promote high performance in the polymerization of styrene (activity < 7700 g mmol(cat.)…”

Homopolymerization of styrenic monomers and their copolymerization with ethylene using group 4 non‐metallocene catalysts

“…The studies on the effect of the type of an electrodonating substituent in styrene on the homopolymerization process catalyzed by organometallic catalysts and the properties of the resulting products are undertaken rarely in contrast to the well-recognized styrene polymerization process. [29][30][31][32][33][34] Moreover, the results seem to be highly dependent on the type of the catalytic system used. The polymerization rate for substituted styrene in the presence of the syndiospecific tetrabenzyltitanium/methylalumoxane system increased in the following order: styrene < pmethylstyrene < p-methoxystyrene.…”