Abstract
Recent decades have witnessed intense research efforts aimed at developing new homogeneous olefin polymerization catalysts, with a primary focus on metal-Cl or metal-hydrocarbyl precursors. Curiously, metal-NR2 precursors have received far less attention. In this contribution, the Zr-amido complex FI2ZrX2 (FI = 2,4-di-tert-butyl-6-((isobutylimino)methyl)phenolate, X = NMe2) is found to exhibit high ethylene polymerization activity and relatively high 1-octene coenchainment selectivity (up to 7.2 mol%) after sequential activation with trimethylaluminum, then Ph3C+B(C6F5)4-. In sharp contrast, catalysts with traditional hydrocarbyl ligands such as benzyl and methyl give low 1-octene incorporation (0-1.0 mol%). This unexpected selectivity persists under scaled/industrial operating conditions and was previously inaccessible with traditional metal-Cl or -hydrocarbyl precursors. NMR, X-ray diffraction, and catalytic control experiments indicate that in this case an FI ligand is abstracted from FI2Zr(NMe2)2 by trimethylaluminum in the activation process to yield a catalytically active cationic mono-FIZr species. Heretofore this process was believed to serve only as a major catalyst deactivation pathway to be avoided. This work demonstrates the importance of investigating diverse precatalyst monodentate σ-ligands in developing new catalyst systems, especially for group 4 olefin polymerization catalysts.
Original language | English (US) |
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Pages (from-to) | 7822-7830 |
Number of pages | 9 |
Journal | Journal of the American Chemical Society |
Volume | 141 |
Issue number | 19 |
DOIs | |
State | Published - May 15 2019 |
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
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CCDC 1914369: Experimental Crystal Structure Determination
Gao, Y. (Creator), Christianson, M. D. (Creator), Wang, Y. (Creator), Chen, J. (Creator), Marshall, S. (Creator), Klosin, J. (Creator), Lohr, T. L. (Creator) & Marks, T. J. (Creator), Cambridge Crystallographic Data Centre, 2019
DOI: 10.5517/ccdc.csd.cc2281v8, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc2281v8&sid=DataCite
Dataset
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CCDC 1914371: Experimental Crystal Structure Determination
Gao, Y. (Creator), Christianson, M. D. (Creator), Wang, Y. (Creator), Chen, J. (Creator), Marshall, S. (Creator), Klosin, J. (Creator), Lohr, T. L. (Creator) & Marks, T. J. (Creator), Cambridge Crystallographic Data Centre, 2019
DOI: 10.5517/ccdc.csd.cc2281xb, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc2281xb&sid=DataCite
Dataset
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CCDC 1914370: Experimental Crystal Structure Determination
Gao, Y. (Creator), Christianson, M. D. (Creator), Wang, Y. (Creator), Chen, J. (Creator), Marshall, S. (Creator), Klosin, J. (Creator), Lohr, T. L. (Creator) & Marks, T. J. (Creator), Cambridge Crystallographic Data Centre, 2019
DOI: 10.5517/ccdc.csd.cc2281w9, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc2281w9&sid=DataCite
Dataset