Preparation of octahydro- and tetrahydro-[1,10]phenanthroline zirconium and hafnium complexes for olefin polymerization

Hwang, Eun Yeong; Park, Geun Ho; Lee, Chun Sun; Kang, Yi Young; Lee, Junseong; Lee, Hyun Ju

doi:10.1039/c4dt03683b

Cited by 16 publications

(10 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The prototype Hf catalyst I was exceptional in terms of the activity and α-olefin incorporation capability. We also reported various types of Hf-complexes ([N,P]Hf(CH 2 Ph) 3 , [N,P,N]HfMe 2 , and [N,N]Hf(CH 2 Ph) 3 -type) with tetrahydroquinoline and tetrahydrophenanthroline framework, which were also inferior to I in terms of both activity and α-olefin incorporation capability [45,46,47]. The Hf-C bonding character was significantly ionic when compared to those of Zr-C and Ti-C bonding, and steric congestion around Hf-center might be crucial for the high activity [48].…”

Section: Resultsmentioning

confidence: 99%

Preparation of Pincer Hafnium Complexes for Olefin Polymerization

et al. 2019

Self Cite

View full text Add to dashboard Cite

Pincer-type [Cnaphthyl, Npyridine, Namido]HfMe2 complex is a flagship among the post-metallocene catalysts. In this work, various pincer-type Hf-complexes were prepared for olefin polymerization. Pincer-type [Namido, Npyridine, Namido]HfMe2 complexes were prepared by reacting in situ generated HfMe4 with the corresponding ligand precursors, and the structure of a complex bearing 2,6-Et2C6H3Namido moieties was confirmed by X-ray crystallography. When the ligand precursors of [(CH3)R2Si-C5H3N-C(H)PhN(H)Ar (R = Me or Ph, Ar = 2,6-diisopropylphenyl) were treated with in situ generated HfMe4, pincer-type [Csilylmethyl, Npyridine, Namido]HfMe2 complexes were afforded by formation of Hf-CH2Si bond. Pincer-type [Cnaphthyl, Sthiophene, Namido]HfMe2 complex, where the pyridine moiety in the flagship catalyst was replaced with a thiophene unit, was not generated when the corresponding ligand precursor was treated with HfMe4. Instead, the [Sthiophene, Namido]HfMe3-type complex was obtained with no formation of the Hf-Cnaphthyl bond. A series of pincer-type [Cnaphthyl, Npyridine, Nalkylamido]HfMe2 complexes was prepared where the arylamido moiety in the flagship catalyst was replaced with alkylamido moieties (alkyl = iPr, cyclohexyl, tBu, adamantyl). Structures of the complexes bearing isopropylamido and adamantylamido moieties were confirmed by X-ray crystallography. Most of the complexes cleanly generated the desired ion-pair complexes when treated with an equivalent amount of [(C18H37)2N(H)Me]+[B(C6F5)4]−, which showed negligible activity in olefin polymerization. Some complexes bearing bulky substituents showed moderate activities, even though the desired ion-pair complexes were not cleanly afforded.

show abstract

Section: Resultsmentioning

confidence: 99%

Preparation of Pincer Hafnium Complexes for Olefin Polymerization

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Accordingly, the polymers generated by III are amorphous, while the polymers generated by 10 – 12 and 16 exhibited melting signals around 100 °C. We also reported various type of Hf complexes ([N,P]Hf(CH 2 Ph) 3 , [N,P,N]HfMe 2 , and [N,N]Hf(CH 2 Ph) 3 -type) with tetrahydroquinoline and tetrahydrophenanthroline frameworks, which were also inferior to III in terms of the α-olefin incorporation capability as well as the activity [50,51,52].…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2019

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…Octahydrophenanthroline was previously employed as a bidentate dianionic ligand and as a precursor for an N‐heterocyclic carbene ligand, yet, to the best of our knowledge, it had not been employed as a core of more elaborate ligands. We prepared it by hydrogenation of 1,10‐phenanthroline using hydrogen at 30 bar and Raney nickel as catalyst following a literature procedure (Scheme ) .…”

Section: Resultsmentioning

confidence: 99%

Aluminum Complexes of Octahydrophenanthroline‐Based Salophan Ligands: Coordination Chemistry and Activity in the Ring‐Opening Polymerization of Lactide

2018

View full text Add to dashboard Cite

Salophan ligands featuring the octahydrophenanthroline core are described for the first time. Two ligand precursors featuring either di-tert-butylphenolate or dichlorophenolate were prepared by 1,10-phenanthroline hydrogenation followed by reaction with bromomethyl-substituted phenols. The ligand precursors react with AlMe 3 to give the [{ONNO}Al-Me]-type complexes as single stereoisomers of averaged C s -symmetry on the NMR timescale. The reactivity of the [a] 5048 Scheme 3. The reactivity of the salophan {ONNN}Al-Me complexes with benzyl alcohol.

show abstract

Preparation of octahydro- and tetrahydro-[1,10]phenanthroline zirconium and hafnium complexes for olefin polymerization

Cited by 16 publications

References 51 publications

Preparation of Pincer Hafnium Complexes for Olefin Polymerization

Preparation of Pincer Hafnium Complexes for Olefin Polymerization

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

Aluminum Complexes of Octahydrophenanthroline‐Based Salophan Ligands: Coordination Chemistry and Activity in the Ring‐Opening Polymerization of Lactide

Contact Info

Product

Resources

About