Octahedral Zirconium Salan Catalysts for Olefin Polymerization: Substituent and Solvent Effects on Structure and Dynamics.

ABSTRACT: Group 4 metal-Salan olefin polymerization catalysts typically have relatively low activity, being slowed down by a pre-equilibrium favoring a non-polymerization active resting state identified as a mer-mer isomer (MM); formation of the polymerization active fac-fac species (FF) requires isomerization. We now show that the chemistry is more subtle than previously realized. Salan variations bearing large, flat substituents can achieve very high activity, and we ascribe this to the stabilization of the FF isomer, which becomes lower in energy than MM. Detailed in situ NMR studies of a fast (o-anthracenyl) and a slow (o-^tBu) Salan precursors, suitably activated, indicate that preferred isomers in solution are different: the fast catalyst pre

SUBMITTER: Dall'Anese A 

PROVIDER: S-EPMC10548417 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature