ansa-Zirconocene Catalysts for Isotactic-Selective Propene Polymerization at High Temperature: A Long Story Finds a Happy Ending

Citations Over TimeTop 10% of 2021 papers

Abstract

Absolute rigidity is rare in the "soft" world of organometallics. Here we introduce two cyclopenta[a]triptycyl ansa-zirconocene catalysts for isotactic-selective propene polymerization, designed by means of an integrated high-throughput experimentation/quantitative structure-activity relationship modeling approach. An ultrarigid ligand precisely wrapped around the Zr center enforces an enzyme-like lock and key fit, effectively hampering undesired reactive events, even at high temperature. Stereodefective units are hardly detectable by 13C NMR in the polymer produced at 120 °C; this corresponds to an enantioselectivity exceeding 6-7 kcal/mol: i.e., less than 1 propene misinsertion every 4000 (and at room temperature, one every ∼40000!).

Related Papers

• → Atactic, Isotactic, and Syndiotactic Methylated Polyhydroxybutyrates: An Unexpected Series of Isomorphic Polymers(2023)28 cited
• → Two New On-Purpose Processes Enhancing Propene Production: Catalytic Cracking of C4 Alkenes to Propene and Metathesis of Ethene and 2-Butene to Propene(2008)32 cited
• → “Chain‐End‐Controlled Isotactic” and “Stereoblock‐Isotactic” Polypropylene: Where Is the Difference?(2002)8 cited
• → Interaction between propene and CoNaX zeolite and exchange of propene hydrogens(1976)3 cited
• → Tacticity of Poly(methyl methacrylate) Polymerized under High Pressure(1963)2 cited