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2,4,6‐Triphenylpyridinium: A Bulky, Highly Electron‐Withdrawing Substituent That Enhances Properties of Nickel(II) Ethylene Polymerization Catalysts.
- Source :
-
Angewandte Chemie . 2/23/2021, Vol. 133 Issue 9, p4616-4619. 4p. - Publication Year :
- 2021
-
Abstract
- The reactivity of NiII and PdII olefin polymerization catalysts can be enhanced by introduction of electron‐withdrawing substituents on the supporting ligands rendering the metal centers more electrophilic. Reported here is a comparison of ethylene polymerization activity of a classical salicyliminato nickel catalyst substituted with the powerful electron‐withdrawing 2,4,6‐triphenylpyridinium (trippy) group to the ‐CF3 analogue. The trippy substituent is substantially more electron‐withdrawing (σmeta=0.63) than the trifluoromethyl group (σmeta=0.43) which results in a ca. 8‐fold increase in catalytic turnover frequency. An additional advantage of trippy is the high steric bulk relative to the trifluoromethyl group. This feature results in a four‐fold increase in polymer molecular weight owing to enhanced retardation of chain transfer. A significant increase in catalyst lifetime is observed as well. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00448249
- Volume :
- 133
- Issue :
- 9
- Database :
- Academic Search Index
- Journal :
- Angewandte Chemie
- Publication Type :
- Academic Journal
- Accession number :
- 148755819
- Full Text :
- https://doi.org/10.1002/ange.202013854