Cationic Pyridylamido Adsorbate on Brønsted Acidic Sulfated Zirconia: A Molecular Supported Organohafnium Catalyst for Olefin Homo- and Co-Polymerization

Jialong Zhang, Alessandro Motta, Yanshan Gao, Madelyn Marie Stalzer, Massimiliano Delferro, Boping Liu, Tracy L. Lohr, Tobin J Marks

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Here we report the combined application of high-resolution solid-state 13C-CPMAS-NMR and FT-IR spectroscopy, elemental analysis, kinetic poisoning/active site counting, variable dielectric constant medium, and DFT computation to characterize the surface chemistry of a pyridylamido hafnium complex (Cat1, L1-HfMe2, L1 = 2,6-diisopropyl-N-{(2-isopropylphenyl)[6-(naphthalen-1-yl)pyridin-2-yl]methyl}aniline) adsorbed on Brønsted acidic sulfated zirconia (ZrS). The spectroscopic and DFT results indicate protonolytic formation of organohafnium cations having a largely electrostatic pyridylamido-Hf-CH3 +···ZrS- interaction with elongated Hf···OZrS distances of ∼2.14 Å. High-molecular-weight polyethylenes and ethylene/1-octene copolymers are obtained with this supported catalyst without an activator/cocatalyst. The DFT calculations reveal that the first ethylene insertion into the Hf-methyl bond has a lower barrier than the corresponding insertion into the Hf-aryl bond of this single-site heterogeneous catalyst.

Original languageEnglish
Pages (from-to)4893-4901
Number of pages9
JournalACS Catalysis
Volume8
Issue number6
DOIs
Publication statusPublished - Jun 1 2018

Fingerprint

Alkenes
Adsorbates
Catalyst supports
Discrete Fourier transforms
Zirconia
Copolymerization
Olefins
Polyethylenes
Ethylene
Hafnium
Aniline
Surface chemistry
Cations
Electrostatics
Infrared spectroscopy
Permittivity
Copolymers
Positive ions
Molecular weight
Nuclear magnetic resonance

Keywords

  • DFT calculations
  • olefin polymerization
  • organohafnium catalyst
  • sulfated oxides
  • supported catalysts

ASJC Scopus subject areas

  • Catalysis

Cite this

Cationic Pyridylamido Adsorbate on Brønsted Acidic Sulfated Zirconia : A Molecular Supported Organohafnium Catalyst for Olefin Homo- and Co-Polymerization. / Zhang, Jialong; Motta, Alessandro; Gao, Yanshan; Stalzer, Madelyn Marie; Delferro, Massimiliano; Liu, Boping; Lohr, Tracy L.; Marks, Tobin J.

In: ACS Catalysis, Vol. 8, No. 6, 01.06.2018, p. 4893-4901.

Research output: Contribution to journalArticle

Zhang, Jialong ; Motta, Alessandro ; Gao, Yanshan ; Stalzer, Madelyn Marie ; Delferro, Massimiliano ; Liu, Boping ; Lohr, Tracy L. ; Marks, Tobin J. / Cationic Pyridylamido Adsorbate on Brønsted Acidic Sulfated Zirconia : A Molecular Supported Organohafnium Catalyst for Olefin Homo- and Co-Polymerization. In: ACS Catalysis. 2018 ; Vol. 8, No. 6. pp. 4893-4901.
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