@article{e1698d788c9a454cb421061759fba5b4,
title = "Cationic Pyridylamido Adsorbate on Br{\o}nsted Acidic Sulfated Zirconia: A Molecular Supported Organohafnium Catalyst for Olefin Homo- and Co-Polymerization",
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 Br{\o}nsted 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 {\AA}. 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.",
keywords = "DFT calculations, olefin polymerization, organohafnium catalyst, sulfated oxides, supported catalysts",
author = "Jialong Zhang and Alessandro Motta and Yanshan Gao and Stalzer, {Madelyn Marie} and Massimiliano Delferro and Boping Liu and Lohr, {Tracy L.} and Marks, {Tobin J.}",
note = "Funding Information: Financial support of this heterogeneous catalytic project by the U.S. Department of Energy through grant DE FG02-03ER15457 to the Institute for Catalysis in Energy Processes (ICEP) at Northwestern University is gratefully acknowledged (J.Z., M.M.S.), while complementary homogeneous catalyst design work was supported by NSF grant CHE-1464488 (T.L.L). The purchase of the NMR instrumentation at IMSERC at Northwestern University was supported by NSF (CHE-1048773). Computational resources supporting this work were provided by the Northwestern University Quest High Performance Computing cluster (T.L.L.) and CINECA award N. HP10CBHAYD 2014 under the ISCRA initiative (A.M). We thank UOP, a Honeywell Company (Des Plaines, IL) for the generous gift of sulfated zirconia. We also thank Albemarle Corp. for a generous gift of triphenylcarbenium tetrakis(pentafluorophenyl)borate, Ph3C+B(C6F5)4−. We thank Y. Wang and J.Z. Chen of Northwestern University for helpful discussions. J.Z. thanks the joint-Ph.D. program supported by China Scholarship Council for fellowships. Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",
year = "2018",
month = jun,
day = "1",
doi = "10.1021/acscatal.8b00611",
language = "English (US)",
volume = "8",
pages = "4893--4901",
journal = "ACS Catalysis",
issn = "2155-5435",
publisher = "American Chemical Society",
number = "6",
}