Stereospecific and Stereoselective Polymerization of 4‐Methyl‐1‐hexene by Enantiomeric Binaphthyl‐Bridged Salen Dichlorozirconium (IV) Complexes

Abstract

Two enantiomers of a chiral binaphthyl-bridged salen dichlorozirconium (IV) complex (namely R-L-1 and S-D-1) were synthesized and tested as pre-catalysts for 4-methyl-1-hexene\ud (4MH) polymerization. Their behavior was compared with that of the same complex in its racemic form. Isotactic poly(4-\ud methyl-1-hexene) was produced in both cases, but the polymerization of racemic 4MH promoted by the\ud optically active catalysts preferentially consumed one antipode,\ud showing some stereoselectivity for the process

FI Catalysts for Olefin Polymerization—A Comprehensive Treatment

“…This reduced phenoxy−amine species afforded isotactic poly(α-olefin)s, whose isotacticity became higher when longer 1-alkenes were applied. As anticipated, enantioselective isospecific polymerization of 4-methyl-1-hexene was possible when using each of the enantiometrically pure complexes …”

Building Porous Ni(Salen)‐Based Catalysts from Waste Styrofoam via Autocatalytic Coupling Chemistry for Heterogeneous Oxidation with Molecular Oxygen

“…[3] 2,3,5-Trimethyl-1,4benzoquinone (TMBQ), as a significant intermediate that stems from the oxidation of 2,3,5-trimethylphenol (TMP), has been heavily deployed in the scale-up synthesis of vitamin E. [4] To date, numerous feasible catalytic systems based on oxidants, including tert-butyl hydroperoxide and hydrogen peroxide, have been exploited for TMBQ production and shown attractive efficiency. [5,6] However, from the perspective of "green" source and safety concern in mass production, molecular oxygen has attracted intensive research attention due to its abundance. [7][8][9] In this regard, metal-salen complexes, possessing a strong axial coordination ability to oxygen, have been proposed as an effective alternative, especially for phenol oxidations.…”

Chlorotitanium (IV) tetradentate Schiff‐base complex immobilized on inorganic supports: Support type and other factors having effect on ethylene polymerization activity

“…Early transition metal complexes with different tetradentate Schiff base ligands, inter alia salen‐type and salan‐type ligands, were tested recently in polymerization and oligomerization of vinyl compounds 1–3. In general, titanium complexes with salen‐type ligands, in contrast to salan complexes, bond metal ions in the pseudoplanar configuration and the chlorides are located in the trans‐position 1(i), 4. Despite that, those complexes are active in styrene polymerization,1(i) yielding syndiotactic polystyrene.…”

“…In general, titanium complexes with salen‐type ligands, in contrast to salan complexes, bond metal ions in the pseudoplanar configuration and the chlorides are located in the trans‐position 1(i), 4. Despite that, those complexes are active in styrene polymerization,1(i) yielding syndiotactic polystyrene. We demonstrated, moreover, in our previous studies2(a,c) that various salen‐type complexes of titanium may produce ethylene oligomers, low molecular weight polyethylene (PE) or high molecular weight PE, depending on the type of the activator used.…”