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Zirconium and titanium complexes supported by tridentate LX2 ligands having two phenolates linked to furan, thiophene, and pyridine donors: precatalysts for propylene polymerization and oligomerization

Agapie, Theodor and Henling, Lawrence M. and DiPasquale, Antonio G. and Rheingold, Arnold L. and Bercaw, John E. (2008) Zirconium and titanium complexes supported by tridentate LX2 ligands having two phenolates linked to furan, thiophene, and pyridine donors: precatalysts for propylene polymerization and oligomerization. Organometallics, 27 (23). pp. 6245-6256. ISSN 0276-7333. https://resolver.caltech.edu/CaltechAUTHORS:AGAo08

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Abstract

Zirconium and titanium complexes with tridentate bis(phenolate)-donor (donor = pyridine, furan and thiophene) ligands have been prepared and investigated for applications in propylene polymerization. The ligand framework has two X-type phenolates connected to the flat heterocyclic L-type donor at the 2,6- or 2.5- positions via direct ring-ring (sp^2-sp^2)linkages. The zirconium and titanium dibenzyl complexes have been prepared by treatment of the neutral bis(phenol)-donor ligands with M(CH_2Ph)_4 (M = Ti, Zr) with loss of 2 equiv of toluene. Titanium complexes with bis(phenolate)pyridine and -furan ligands and zirconium complexes with bis(phenolate)pyridine and -thiophene ligands have been characterized by single-crystal X-ray diffraction. The solid-state structures of the bis(benzyl)titanium complexes are roughly C_2 symmetric, while the zirconium derivatives display C_s and C^1 symmetry. The bis(phenolate)pyridine titanium complexes are structurally affected by the size of the substituents substituents (CMe_3 or CEt_3) ortho to the oxygens, the larger group leading to a larger C_2 distortion. Both titanium and zirconium dibenzyl complexes were found to be catalyst precursors for the polymerization of propylene upon activation with methylaluminoxane (MAO). The activities observed for the zirconium complexes are particularly notable, exceeding 10^6 g polypropylene/mol Zr center dot h in some cases. The bis(phenolate)pyridine titanium analogues are about 10^3 times less active, but generate polymers of higher molecular weight. When activated with MAO, the titanium bis(phenolate)furan and bis(phenolate)thiophene systems were found to promote propylene oligomerization.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/om800136yDOIArticle
http://pubs.acs.org/doi/abs/10.1021/om800136yPublisherArticle
ORCID:
AuthorORCID
Agapie, Theodor0000-0002-9692-7614
Additional Information:© 2008 American Chemical Society. Publication Date (Web): 06 November 2008. This work has been supported by the USDOE Office of Basic Energy Sciences (Grant No. DEFG03-85ER13431). The authors thank Michael Day (Caltech) for assistance in obtaining the X-ray crystal structures. We are grateful to Mona Shahgholi (Caltech) for help with HRMS and Sara Klamo (Dow) for obtaining the GPC data.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG03-85ER13431
Subject Keywords:OSCILLATING METALLOCENE CATALYSTS; AMINE BIS(PHENOLATE) LIGANDS; LIVING POLYMERIZATION; OLEFIN POLYMERIZATION; EXTRA DONOR; PYRIDINE-2,6-BIS(ARYLOXIDE) LIGANDS; 1-HEXENE POLYMERIZATION; PROPENE POLYMERIZATION; ISOBUTYL INITIATORS; CATIONIC ZIRCONIUM.
Issue or Number:23
Record Number:CaltechAUTHORS:AGAo08
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:AGAo08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13385
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:14 May 2009 22:53
Last Modified:03 Oct 2019 00:36

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