Novel Titanium Catalysts Bearing an [O, N, S] Tridentate Ligand for Ethylene Homo‐ and Copolymerization

Abstract

Summary: By a sidearm approach, a series of titanium complexes bearing an [O, N, S] tridentate ligand have been synthesized and proven to be highly active for ethylene polymerization. The complexes also show excellent ability to copolymerize ethylene with hex‐1‐ene and norbornene. The effects of the different sidearms on the catalytic behavior of the complexes were studied in detail.The copolymerization of ethylene with hex‐1‐ene using titanium complexes bearing [O, N, S] tridentate ligands as catalysts.imageThe copolymerization of ethylene with hex‐1‐ene using titanium complexes bearing [O, N, S] tridentate ligands as catalysts.

TiIV Complexes of Redox‐Active Schiff Bases

“…Indeed, ref. [9] reported two products from salicylaldehyde but provided no explanation, whereas in our hands the S-S linked dimer was one of them. The thiazole form was the sole product upon prolonged heating of the reaction mixture in air.…”

“…Aminothiophenol-derived analogues, with their larger, softer sulfur atoms, should undergo easier oxidations (Scheme 2). Mixed-ligand complexes of Ti IV alkoxides and salicylaldehyde-2-mercaptoanil were first reported in 1974; [8] they were found to catalyze ethylene polymerization, [9] which was attributed to the soft thiophenolate-Ti interaction and its steric requirements. Their electrochemistry was not examined.…”

High norbornene incorporation in ethylene-norbornene copolymerization with a bis(α-alkyloxoimine) titanium-MAO catalyst

“…Many non-metallocenes titanium complexes such as bis(pyrrolide-imine) titanium [22,23], bis(imino-indolide) titanium [24], bis(-enaminoketonato) titanium [25], [2-(2,6-dialkylphenylamino)-1-phenylethoxy TiCl 2 ] [26], titanium complexes bearing tridentate [O  NX R ] (X = S, O, Se, P) ligands [27,28], and bis(-diketiminato) titanium [29] were also used to effectively copolymerize ethylene (E) and norbornene (NBE) in the presence of MAO or MMAO. However, fewer successful examples have appeared for the efficient synthesis of random, high-molecular-weight copolymers with high NBE contents (> 50 mol%), which typically possess high T g (> 150 °C).…”

Treatment of core‐binding‐factor in acute myelogenous leukemia with fludarabine, cytarabine, and granulocyte colony‐stimulating factor results in improved event‐free survival

“…Of the successful postmetallocene catalysts developed,1–3 the complexes possessing phenoxyimine ligands are one of the promising examples 8–14. Tang et al have reported that titanium (IV) catalysts bearing phenoxyimine ligand with side‐arm, i.e., [O − NP], [O − NO], or [O − NS] tridentate ligands, were robust and highly active for ethylene homo‐ and copolymerization with linear α‐olefin and cycloolefin, and so forth 15–19. Qian and coworkers20–22 and Lancaster and coworkers23, 24 reported the synthesis of half‐titanocenes containing phenoxyimine ligands and their use as catalysts for olefin polymerization.…”