Related Experiment Video
Updated: May 13, 2026

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
Isospecific propylene polymerization with in situ generated bis(phenoxy-amine)zirconium and hafnium single site
Haruyuki Makio1, Aitha Vishwa Prasad, Hiroshi Terao
1Mitsui Chemicals Singapore R&D Centre, Pte. Ltd. 50 Science Park Road, #06-08 The Kendall, Singapore Science Park II, Singapore 117406. haruyuki.makio@mitsui-chem.co.jp
Abstract:
Bis(phenoxy-imine) Zr and Hf complexes were activated with (i)Bu3Al or (i)Bu2AlH in conjunction with Ph3CB(C6F5)4 and tested as catalysts for propylene polymerization with emphasis on the enantioselectivity of the isospecific species and the single site polymerization characteristics. The isoselective species was identified as the in situ generated bis(phenoxy-amine) complex whose isoselectivity was sensitive to subtle changes in ligand structure. By employing specific substituents at certain key positions the isotacticity reached an extremely high level comparable to high-end commercial isotactic polypropylenes (Tm > 160 °C). Single site polymerization characteristics depended upon the efficiency and selectivity of the in situ imine reduction which is sensitive to the substituent on the imine nitrogen and the reaction conditions. By using (i)Bu2AlH as a reducing agent, quantitative imine reduction can be achieved with a stoichiometric amount of the reducing agent. This lower alkylaluminum loading is beneficial for the catalyst and significantly enhances the polymerization activity and the molecular weight of the resultant polymer.
More Related Videos
Related Concept Videos
Ziegler–Natta Chain-Growth Polymerization: Overview
Cationic Chain-Growth Polymerization: Mechanism
Olefin Metathesis Polymerization: Overview
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Free-Radical Chain Reaction and Polymerization of Alkenes
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)

