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Preparation of Half- and Post-Metallocene Hafnium Complexes with Tetrahydroquinoline and Tetrahydrophenanthroline Frameworks for Olefin Polymerization

1
Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea
2
Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Korea
3
LG Chem, Ltd., 188, Munji-ro, Yuseong-gu Daejeon 305-738, Korea
*
Author to whom correspondence should be addressed.
Polymers 2019, 11(7), 1093; https://doi.org/10.3390/polym11071093
Received: 25 May 2019 / Revised: 24 June 2019 / Accepted: 25 June 2019 / Published: 27 June 2019
(This article belongs to the Special Issue Catalytic Olefin Polymerisation and Polyolefins)
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Abstract

Hafnium complexes have drawn attention for their application as post-metallocene catalysts with unique performance in olefin polymerization. In this work, a series of half-metallocene HfMe2 complexes, bearing a tetrahydroquinoline framework, as well as a series of [Namido,N,Caryl]HfMe2-type post-metallocene complexes, bearing a tetrahydrophenanthroline framework, were prepared; the structures of the prepared Hf complexes were unambiguously confirmed by X-ray crystallography. When the prepared complexes were reacted with anhydrous [(C18H37)2N(H)Me]+[B(C6F5)4], desired ion-pair complexes, in which (C18H37)2NMe coordinated to the Hf center, were cleanly afforded. The activated complexes generated from the half-metallocene complexes were inactive for the copolymerization of ethylene/propylene, while those generated from post-metallocene complexes were active. Complex bearing bulky isopropyl substituents (12) exhibited the highest activity. However, the activity was approximately half that of the prototype pyridylamido-Hf Dow catalyst. The comonomer incorporation capability was also inferior to that of the pyridylamido-Hf Dow catalyst. However, 12 performed well in the coordinative chain transfer polymerization performed in the presence of (octyl)2Zn, converting all the fed (octyl)2Zn to (polyolefinyl)2Zn with controlled lengths of the polyolefinyl chain. View Full-Text
Keywords: post-metallocene; half-metallocene; hafnium complex; olefin polymerization; coordinative chain transfer polymerization post-metallocene; half-metallocene; hafnium complex; olefin polymerization; coordinative chain transfer polymerization
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Baek, J.W.; Kwon, S.J.; Lee, H.J.; Kim, T.J.; Ryu, J.Y.; Lee, J.; Shin, E.J.; Lee, K.S.; Lee, B.Y. Preparation of Half- and Post-Metallocene Hafnium Complexes with Tetrahydroquinoline and Tetrahydrophenanthroline Frameworks for Olefin Polymerization. Polymers 2019, 11, 1093.

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