Unexpected Precatalyst σ-Ligand Effects in Phenoxyimine Zr-Catalyzed Ethylene/1-Octene Copolymerizations

Yanshan Gao, Matthew D. Christianson, Yang Wang, Jiazhen Chen, Steve Marshall, Jerzy Klosin, Tracy L. Lohr, Tobin J Marks

Research output: Contribution to journalArticle

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 languageEnglish
Pages (from-to)7822-7830
Number of pages9
JournalJournal of the American Chemical Society
Volume141
Issue number19
DOIs
Publication statusPublished - May 15 2019

Fingerprint

Copolymerization
Ethylene
Metals
Ligands
Polymerization
Catalysts
Alkenes
Olefins
Chemical activation
Catalyst deactivation
X-Ray Diffraction
Nuclear magnetic resonance
X ray diffraction
ethylene
1-octene
Research
Experiments

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Unexpected Precatalyst σ-Ligand Effects in Phenoxyimine Zr-Catalyzed Ethylene/1-Octene Copolymerizations. / Gao, Yanshan; Christianson, Matthew D.; Wang, Yang; Chen, Jiazhen; Marshall, Steve; Klosin, Jerzy; Lohr, Tracy L.; Marks, Tobin J.

In: Journal of the American Chemical Society, Vol. 141, No. 19, 15.05.2019, p. 7822-7830.

Research output: Contribution to journalArticle

Gao, Yanshan ; Christianson, Matthew D. ; Wang, Yang ; Chen, Jiazhen ; Marshall, Steve ; Klosin, Jerzy ; Lohr, Tracy L. ; Marks, Tobin J. / Unexpected Precatalyst σ-Ligand Effects in Phenoxyimine Zr-Catalyzed Ethylene/1-Octene Copolymerizations. In: Journal of the American Chemical Society. 2019 ; Vol. 141, No. 19. pp. 7822-7830.
@article{3861df30447547e297d156044eb2fec7,
title = "Unexpected Precatalyst σ-Ligand Effects in Phenoxyimine Zr-Catalyzed Ethylene/1-Octene Copolymerizations",
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.",
author = "Yanshan Gao and Christianson, {Matthew D.} and Yang Wang and Jiazhen Chen and Steve Marshall and Jerzy Klosin and Lohr, {Tracy L.} and Marks, {Tobin J}",
year = "2019",
month = "5",
day = "15",
doi = "10.1021/jacs.9b01445",
language = "English",
volume = "141",
pages = "7822--7830",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "19",

}

TY - JOUR

T1 - Unexpected Precatalyst σ-Ligand Effects in Phenoxyimine Zr-Catalyzed Ethylene/1-Octene Copolymerizations

AU - Gao, Yanshan

AU - Christianson, Matthew D.

AU - Wang, Yang

AU - Chen, Jiazhen

AU - Marshall, Steve

AU - Klosin, Jerzy

AU - Lohr, Tracy L.

AU - Marks, Tobin J

PY - 2019/5/15

Y1 - 2019/5/15

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85065778325&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85065778325&partnerID=8YFLogxK

U2 - 10.1021/jacs.9b01445

DO - 10.1021/jacs.9b01445

M3 - Article

C2 - 31017398

AN - SCOPUS:85065778325

VL - 141

SP - 7822

EP - 7830

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 19

ER -