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

Abstract

The dibenzyl zirconium(IV) complex (4) incorporating with a carbazolyl(Cbz)-substituted [OSSO]-type bis(phenolate) ligand was synthesized. Upon activation with dried modified methylaluminoxane (dMMAO), precatalyst 4 at relatively low catalyst loadings was found to promote the 1,2-regioselective oligomerization of 1-hexene to produce the corresponding vinylidene-ended oligomers with moderate turnover frequencies (TOFs) up to 2080 h−1. The 13C NMR analysis of the resulting oligomers revealed the formation of dimer-enriched oligo(1-hexene)s in 39–62% distributions. The precatalyst 4 with dried methylaluminoxane (dMAO) also exhibited good performance in the polymerization of styrene yielding isotactic polystyrenes ([mm] > 99%) with quite large molecular weights (Mw < 508,100 g mol−1) and relatively high catalytic activity (up to 2810 g mmol(4)−1 h−1).

Catalytic Systems Based on Cp2ZrX2 (X = Cl, H), Organoaluminum Compounds and Perfluorophenylboranes: Role of Zr,Zr- and Zr,Al-Hydride Intermediates in Alkene Dimerization and Oligomerization

“…The same activity towards the alkene was observed for the adducts of complex 7 with MAO [47]. Thus, the Cp2ZrCl2-XAlBu i 2 (X = H, Bu i ) and [Cp2ZrH2]2-ClAlEt2 systems activated by (Ph3C)[B(C6F5)4] or B(C6F5)3 are able to accomplish selective dimerization and oligomerization of alkenes to give head-to-tail vinylidene products, similarly to systems based on Zr complexes and МАО [3,[6][7][8]13,[57][58][59]. Among the post-metallocene Zr and Hf complexes with [ONNO]-type amino-bis(phenolate) ligands activated by neutral B(C6F5)3, the best selectivity to 1-hexene dimers (up to 97%) was found to hafnium catalysts [60].…”

“…Similar two-site catalysis is known for alkene polymerization in the presence of group 4 metal complexes [65]. Nevertheless, certain issues remain unanswered: how the bis-zirconium structures are activated; what is the principle of formation [3,[6][7][8]13,[57][58][59]. Among the post-metallocene Zr and Hf complexes with [ONNO]-type amino-bis(phenolate) ligands activated by neutral B(C 6 F 5 ) 3 , the best selectivity to 1-hexene dimers (up to 97%) was found to hafnium catalysts [60].…”

Fair Look at Coordination Oligomerization of Higher α-Olefins

“…At the same time, the benzimidazole analog 73 catalyzed non-selective oligomerization regardless of the type of activator [138]. Zirconium complexes with [OSSO]-type ligands 74, 75 [139], and 76 [140] (Scheme 6) in the presence of dried modified methylaluminoxane (dMMAO) catalyzed the formation of lower 1-hexene oligomers with excellent vinylidene selectivity. Apparently, the mechanism of the oligomerization catalyzed by 72-76 is similar to the mechanism of zirconocene-catalyzed oligomerization.…”

Preparation, spectroscopic analysis, and biological assessment of heteroleptic Zr(II) and Pd(II) complexes from Otc/Sal mixed ligands

“…In the Zr(II)Otc/Sal metal complex, aromatic ring protons are assigned as multiplet between δ7.023-7.279 ppm. These protons moved upfield slightly to confirm the coordination of metal ions with the ligands [40]. A single peak at δ1.047-1.082 ppm, was assigned to the methyl proton.…”