Synthesis of Early Transition Metal Bisphenolate Complexes and Their Use as Olefin Polymerization Catalysts

Abstract

Bisphenolate ligands with pyridine- and benzene-diyl linkers have been synthesized and metalated with group 4 and 5 transition metals. The solid-state structures of some of the group 4 complexes have been solved. The titanium, zirconium, hafnium, and vanadium complexes were tested for propylene polymerization and ethylene/1-octene copolymerization activities with methylaluminoxane as cocatalyst. The vanadium(III) precatalyst is the most active for propylene polymerization and shows the highest 1-octene incorporation for ethylene/1-octene copolymerization. The zirconium(IV) precatalyst was the most active for propylene polymerization of the group 4 precatalysts. Titanium(IV) and zirconium(IV) precatalysts with pyridine-diyl linkers provided mixtures of isotactic and atactic polypropylene while titanium(IV) precatalysts with benzene-diyl linkers gave atactic polypropylene only. The hafnium(IV) precatalyst with a pyridine-diyl linker generated moderately isotactic polypropylene.

Olefin Polymerization with Non-metallocene Catalysts (Early Transition Metals)

“…Taking into account the above reports (vanadium complexes using chelate anionic and neutral donor ligands) [91][92][93][94][95][96][97][98], as described above, control, stabilization of the oxidation state, catalytically active species) by an appropriate ligand modification seems to be a key for the efficient catalyst with vanadium(III), …”

“…Copolymerizations of ethylene with 1-hexene, norbornene were attempted, but the activities decreased and the resultant polymers possessed a mixture of coplymers with different compositions estimated by their DSC thermograms [96]. Vanadium(III) complex containing bis(phenoxy)pyridine ligand (25) showed remarkable catalytic activity for propylene polymerization in the presence of MAO (activity 803 kg-PP/mol-VÁh, propylene 5 atm in toluene at 0 8C for 30 min, Al/V = 3000), affording high molecular weight polymer with uniform molecular weight distribution (M w = 1.17 9 10 6 , M w /M n = 2.03) [98]. The resultant polymer possessed large extent of regio irregular as generally seen in those prepared by vanadium catalysts.…”

Synthese von meta‐Terphenyl‐2,2′′‐diolen durch anodische C‐C‐Kreuzkupplungen

“…Besonders interessant sind OCO‐Pincerkomplexe, die strukturell auf meta ‐Terphenyl‐2,2′′‐diolen basieren. Als Metalle können Cr, Mo, W, Ti, Zr, Ta, Sm und Yb genutzt werden. Erfolgreiche Anwendungen der meta ‐Terphenyl‐2,2′′‐diole als Pincerliganden wurde bereits für Sauerstoff‐ und Stickstoffübertragungsreaktionen, Polymerisation von Acetylenen und Olefinen, Alkenisomerisation, Nitren‐ und Carbengruppenübertragungen, O 2 ‐ und C‐H‐Aktivierung, Disulfidreduktionen und aerobe Oxidationen nachgewiesen.…”

Copolymerization of ethylene with norbornene or 1-octene using supported ionic liquid systems

“…Only scarce literature data concerns application of vanadium catalysts for ethylene/1-octene copolymerization. Although the vanadium compounds reveal lower activities as compared to analogous zirconium, titanium, or hafnium, they give better 1-octene incorporation in copolymer chain [26]. In case of heterogeneous catalyst systems for ethylene/1-octene copolymerization, both method of heterogenization and type of solid support have considerable influence on the amount of comonomer units incorporated in polymer chain, which can be increased [27] or decreased [28].…”