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Published July 14, 2014 | Published + Supplemental Material
Journal Article Open

Bimetallic Zirconium Amine Bis(phenolate) Polymerization Catalysts: Enhanced Activity and Tacticity Control for Polyolefin Synthesis

Abstract

Binucleating multidentate amine bis(phenolate) ligands with rigid terphenyl backbones were designed to support two zirconium centers locked in close proximity. Polymerizations of propylene or 1-hexene with the synthesized bimetallic precatalysts resulted in polymers with significantly higher isotacticity (up to 79% mmmm) in comparison to the stereoirregular polymers produced with previously reported C_s-symmetric monometallic analogues. The bimetallic precatalysts also display higher activity (up to 124 kg of poly(1-hexene) (mmol of Zr)^(−1) h^(–1)), in comparison to the monometallic analogues, and among the highest activities reported for nonmetallocene catalysts. The stereocontrol is consistent with a bimetallic mechanism involving remote steric interactions with the ligand sphere of the second metal center.

Additional Information

© 2014 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Received: June 9, 2014. Publication Date (Web): June 18, 2014. We are grateful to Dow Chemical, Caltech, and the ACS PRF for funding. We thank Dr. Mike Takase, Lawrence M. Henling, and Emily Tsui for crystallographic assistance. The Bruker KAPPA APECII X-ray diffractometer was purchased via an NSF CRIF:MU award to Caltech (CHE-063-9094). The 400 MHz NMR spectrometer was purchased via an NIH award (RR027690).

Attached Files

Published - om500608j.pdf

Supplemental Material - om500608j_si_001.pdf

Supplemental Material - om500608j_si_002.cif

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August 20, 2023
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