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Copolymerization of Ethylene with Selected Vinyl Monomers Catalyzed by Group 4 Metal and Vanadium Complexes with Multidentate Ligands: A Short Review. Polymers (Basel) 2021; 13:polym13244456. [PMID: 34961007 PMCID: PMC8708287 DOI: 10.3390/polym13244456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/13/2021] [Accepted: 12/16/2021] [Indexed: 11/17/2022] Open
Abstract
This paper gives a short overview of homogeneous post-metallocene catalysts based on group 4 metal and vanadium complexes bearing multidentate ligands. It summarizes the catalytic behavior of those catalysts in copolymerization of ethylene with 1-olefins, with styrenic monomers and with α,ω-alkenols. The review is focused on finding correlations between the structure of a complex, its catalyst activity and comonomer incorporation ability, as well as the microstructure of the copolymer chains.
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2
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Kumar S, Dholakiya BZ, Jangir R. Role of organometallic complexes in olefin polymerization: a review report. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2021.122066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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3
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Hao H, Bagnol T, Pucheault M, Schafer LL. Using Catalysts To Make Catalysts: Titanium-Catalyzed Hydroamination To Access P,N-Ligands for Assembling Catalysts in One Pot. Org Lett 2021; 23:1974-1979. [PMID: 33661014 DOI: 10.1021/acs.orglett.0c04212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using a diamido-bis(amidate) titanium precatalyst, the hydroamination of alkynylphosphines afforded phosphinoenamine products. After reduction, 2-aminophosphines are prepared in excellent yield and on gram scale. A broad variety of alkynylphosphines and primary amines with different electronic and steric features are tolerated in this sequential transformation, enabling the rapid assembly of a collection of ligands. Additionally, intermediate phosphinoenamines can be used directly as proligands for coordination to transition metals using protonolysis or salt metathesis reactions. These transformations result in easy-to-use one pot protocols to prepare metal P,N-complexes for catalysis or small molecule activation.
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Affiliation(s)
- Han Hao
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC Canada, V6T1Z1
| | - Thibault Bagnol
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC Canada, V6T1Z1.,Institut des Sciences Moléculaires Université de Bordeaux, Institut Européen de Chimie et Biologie 2 Rue Robert Escarpit, 33600 Pessac, France
| | - Mathieu Pucheault
- Institut des Sciences Moléculaires Université de Bordeaux, Institut Européen de Chimie et Biologie 2 Rue Robert Escarpit, 33600 Pessac, France
| | - Laurel L Schafer
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC Canada, V6T1Z1
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4
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Park KL, Baek JW, Moon SH, Bae SM, Lee JC, Lee J, Jeong MS, Lee BY. Preparation of Pyridylamido Hafnium Complexes for Coordinative Chain Transfer Polymerization. Polymers (Basel) 2020; 12:E1100. [PMID: 32403453 PMCID: PMC7285347 DOI: 10.3390/polym12051100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/02/2020] [Accepted: 05/07/2020] [Indexed: 12/04/2022] Open
Abstract
The pyridylamido hafnium complex (I) discovered at Dow is a flagship catalyst among postmetallocenes, which are used in the polyolefin industry for PO-chain growth from a chain transfer agent, dialkylzinc. In the present work, with the aim to block a possible deactivation process in prototype compound I, the corresponding derivatives were prepared. A series of pyridylamido Hf complexes were prepared by replacing the 2,6-diisopropylphenylamido part in I with various 2,6-R2C6H3N-moieties (R = cycloheptyl, cyclohexyl, cyclopentyl, 3-pentyl, ethyl, or Ph) or by replacing 2-iPrC6H4C(H)- in I with the simple PhC(H)-moiety. The isopropyl substituent in the 2-iPrC6H4C(H)-moiety influences not only the geometry of the structures (revealed by X-ray crystallography), but also catalytic performance. In the complexes bearing the 2-iPrC6H4C(H)-moiety, the chelation framework forms a plane; however, this framework is distorted in the complexes containing the PhC(H)-moiety. The ability to incorporate α-olefin decreased upon replacing 2-iPrC6H4C(H)-with the PhC(H)-moiety. The complexes carrying the 2,6-di(cycloheptyl)phenylamido or 2,6-di(cyclohexyl)phenylamido moiety (replacing the 2,6-diisopropylphenylamido part in I) showed somewhat higher activity with greater longevity than did prototype catalyst I.
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Affiliation(s)
- Kyung Lee Park
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea; (K.L.P.); (J.W.B.); (S.H.M.); (S.M.B.); (J.C.L.)
| | - Jun Won Baek
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea; (K.L.P.); (J.W.B.); (S.H.M.); (S.M.B.); (J.C.L.)
| | - Seung Hyun Moon
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea; (K.L.P.); (J.W.B.); (S.H.M.); (S.M.B.); (J.C.L.)
| | - Sung Moon Bae
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea; (K.L.P.); (J.W.B.); (S.H.M.); (S.M.B.); (J.C.L.)
| | - Jong Chul Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea; (K.L.P.); (J.W.B.); (S.H.M.); (S.M.B.); (J.C.L.)
| | - Junseong Lee
- Department of Chemistry, Chonnam National University, Gwangju 500-757, Korea;
| | - Myong Sun Jeong
- Intellectual Property Education Center, Anyang University, Anyang 708-113, Korea;
| | - Bun Yeoul Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea; (K.L.P.); (J.W.B.); (S.H.M.); (S.M.B.); (J.C.L.)
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5
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Preparation of Half- and Post-Metallocene Hafnium Complexes with Tetrahydroquinoline and Tetrahydrophenanthroline Frameworks for Olefin Polymerization. Polymers (Basel) 2019; 11:polym11071093. [PMID: 31252659 PMCID: PMC6680767 DOI: 10.3390/polym11071093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 01/27/2023] Open
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.
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Kwon SJ, Baek JW, Lee HJ, Kim TJ, Ryu JY, Lee J, Shin EJ, Lee KS, Lee BY. Preparation of Pincer Hafnium Complexes for Olefin Polymerization. Molecules 2019; 24:E1676. [PMID: 31035708 PMCID: PMC6540127 DOI: 10.3390/molecules24091676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 11/17/2022] Open
Abstract
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.
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Affiliation(s)
- Su Jin Kwon
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea.
| | - Jun Won Baek
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea.
| | - Hyun Ju Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea.
| | - Tae Jin Kim
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea.
| | - Ji Yeon Ryu
- Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Korea.
| | - Junseong Lee
- Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Korea.
| | - Eun Ji Shin
- LG Chem, Ltd., 188, Munji-ro, Yuseong-gu Daejeon 305-738, Korea.
| | - Ki Soo Lee
- LG Chem, Ltd., 188, Munji-ro, Yuseong-gu Daejeon 305-738, Korea.
| | - Bun Yeoul Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea.
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Alonso C, Martín-Encinas E, Rubiales G, Palacios F. Reliable Synthesis of Phosphino- and Phosphine Sulfide-1,2,3,4-Tetrahydroquinolines and Phosphine Sulfide Quinolines. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700258] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Concepción Alonso
- Departamento de Química Orgánica I; Facultad de Farmacia and Centro de Investigacion Lascaray (Lascaray Research Center); Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU); Paseo de la Universidad 7 01006 Vitoria Spain
| | - Endika Martín-Encinas
- Departamento de Química Orgánica I; Facultad de Farmacia and Centro de Investigacion Lascaray (Lascaray Research Center); Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU); Paseo de la Universidad 7 01006 Vitoria Spain
| | - Gloria Rubiales
- Departamento de Química Orgánica I; Facultad de Farmacia and Centro de Investigacion Lascaray (Lascaray Research Center); Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU); Paseo de la Universidad 7 01006 Vitoria Spain
| | - Francisco Palacios
- Departamento de Química Orgánica I; Facultad de Farmacia and Centro de Investigacion Lascaray (Lascaray Research Center); Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU); Paseo de la Universidad 7 01006 Vitoria Spain
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Preparation of "Constrained Geometry" Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization. Molecules 2017; 22:molecules22020258. [PMID: 28208780 PMCID: PMC6155698 DOI: 10.3390/molecules22020258] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 02/01/2017] [Accepted: 02/07/2017] [Indexed: 11/17/2022] Open
Abstract
The Me₂Si-bridged ansa-Cp/amido half-metallocene, [Me₂Si(η⁵-Me₄C₅)(NtBu)]TiCl₂, termed a "constrained-geometry catalyst (CGC)", is a representative homogeneous Ziegler catalyst. CGC derivatives with the [1,2]azasilinane framework, in which the amide alkyl substituent is joined by the Si-bridge, were prepared, and the catalytic performances of these species was studied. Me₄C₅HSi(Me)(CH₂CH=CH₂)-NH(C(R)(R')CH=CH₂) (R, R' = H or methyl; Me₄C₅H = tetramethylcyclopentadienyl) was susceptible to ring closure metathesis (RCM) when treated with Schrock's Mo-catalyst to afford -Si(Me₄C₅H)(Me)CH₂CH=CHC(R)(R')NH- containing a six-membered ring framework. Using the precursors and the products of RCM, various CGC derivatives, i.e., [-Si(η⁵-Me₄C₅)(Me)CH₂CH=CHC(R)(H)N-]TiMe₂ (13, R = H; 15, R = Me), [-Si(η⁵-Me₄C₅)(Me)CH₂CH₂CH₂CH₂N]TiMe₂ (14), [(η⁵-Me₄C₅)Si(Me)(CH₂CH=CH₂)NCH₂CH=CH₂]TiMe₂ (16), [(η⁵-Me₄C₅)Si (Me)(CH=CH₂)NCH₂CH=CH₂]TiMe₂ (17), and [(η⁵-Me₄C₅)Si(Me)(CH₂CH₃)NCH₂CH₂CH₃]TiMe₂ (18), were prepared. The catalytic activity of the newly prepared complexes was lower than that of CGC when activated with [Ph₃C][B(C₆F₅)₄]/iBu₃Al. However, the catalytic activity of these species was improved by using tetrabutylaluminoxane ([iBu₂Al]₂O) instead of iBu₃Al and the activity of 14/[Ph₃C][B(C₆F₅)₄]/[iBu₂Al]₂O was comparable to that of CGC/[Ph₃C][B(C₆F₅)₄]/iBu₃Al (4.7 and 5.0 × 10⁶ g/mol-Ti, respectively). Advantageously, the newly prepared complexes produced higher molecular weight poly(ethylene-co-1-octene)s than CGC.
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Du MR, Zhang XB, Si SM, Wang L. Theoretical insights into the reaction of Cp*(Cl)Hf(diene) with isonitriles. RSC Adv 2017. [DOI: 10.1039/c7ra08981c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The reaction of Cp*(Cl)Hf(2,3-dimethylbutadiene) with isonitriles is theoretically investigated, and detailed elementary reactions and the substitution effects are examined.
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Affiliation(s)
- Ming-Ran Du
- School of Chemical Engineering
- Anhui University of Science and Technology
- Huainan
- People's Republic of China
| | - Xiang-Biao Zhang
- School of Chemical Engineering
- Anhui University of Science and Technology
- Huainan
- People's Republic of China
| | - Sheng-Meng Si
- School of Chemical Engineering
- Anhui University of Science and Technology
- Huainan
- People's Republic of China
| | - Lei Wang
- Department of Chemistry
- Huaibei Normal University
- Huaibei
- People's Republic of China
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Hafeez M, Riaz M. Aminopyridine stabilized group-IV metal complexes and their applications. APPLIED PETROCHEMICAL RESEARCH 2016. [DOI: 10.1007/s13203-016-0170-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Zhao H, Li X, Zhang S, Sun H. Synthesis and Characterization of Iron, Cobalt, and Nickel [PNP] Pincer Amido Complexes by N-H Activation. Z Anorg Allg Chem 2015. [DOI: 10.1002/zaac.201500568] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Hwang EY, Park GH, Lee CS, Kang YY, Lee J, Lee BY. Preparation of octahydro- and tetrahydro-[1,10]phenanthroline zirconium and hafnium complexes for olefin polymerization. Dalton Trans 2015; 44:3845-55. [PMID: 25611680 DOI: 10.1039/c4dt03683b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Post-metallocenes were constructed for olefin polymerization using 1,2,3,4,7,8,9,10-octahydro[1,10]phenanthroline and 1,2,3,4-tetrahydro[1,10]phenanthroline derivatives. A series of zirconium complexes - LZrCl2(NHMe2)2 [L = 2,9-H2-C12H12N2 (4), 2,9-Me2-C12H12N2 (5), 2,9-nBu2-C12H12N2 (6), and 2,9-iPr2-C12H12N2 (7)] - and hafnium complexes - LHfCl2(NHMe2)2 [L = 2,9-H2-C12H12N2 (8), 2,9-Me2-C12H12N2 (9), 2,9-nBu2-C12H12N2 (10), and 2,9-iPr2-C12H12N2 (11)] - were synthesized via the reaction of octahydro[1,10]phenanthrolines (2,9-R2-C12H12(NH)2) with (Me2N)2MCl2 (DME). The reaction of 2,9-R2-C12H12(NH)2 with (PhCH2)2ZrCl2 in the presence of a small amount of THF afforded a series of THF adduct analogs, i.e., LZrCl2(THF)2 [L = 2,9-H2-C12H12N2 (12), 2,9-Me2-C12H12N2 (13), 2,9-nBu2-C12H12N2 (14), and 2,9-iPr2-C12H12N2 (15)]. The treatment of 12 and 13 with excess Me3Al resulted in the formation of unexpected complexes, i.e., (η(4)-LAlMe2)ZrCl2(Me) [L = 2,9-H2-C12H12N2 (16) and 2,9-Me2-C12H12N2 (17)], in which the Me2Al unit forms a five-membered ring through binding with the two nitrogen donors and the MeCl2Zr unit slips to an η(4)-binding mode containing the N-C-C-N fragment. The treatment of tetrahydro[1,10]phenanthrolines [2,9-R2-C12NH9(NH)] with M(CH2Ph)4 afforded tribenzyl zirconium complexes LZr(CH2Ph)3 - [L = 2,9-Me2-C12NH9N (18) and 2,9-nBu2-C12NH9N (19)] - and hafnium complexes - LHf(CH2Ph)3 [L = 2,9-Me2-C12NH9N (20), 2,9-nBu2-C12NH9N (21), and 2,9-iPr2-C12NH9N (22)]. The structures of 4, 5, 12, 17, and 22 were elucidated by X-ray crystallography. The newly prepared complexes were screened for ethylene/1-octene copolymerization activity: 12 and 16 were potent catalysts (activities of 74 × 10(6) g mol-Zr h(-1) at ∼120 °C under 30 bar ethylene) for the production of wax-like low-molecular weight polyethylene (Mn: ∼5000), which is widely used in industry.
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Affiliation(s)
- Eun Yeong Hwang
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, South Korea
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Casimiro M, Guedes GP, Iglesias MJ, López Ortiz F. Synthesis of P-stereogenic compounds based on the diastereoselective ortho-lithiation of phosphinimidic amides. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.tetasy.2014.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Lee CS, Park JH, Hwang EY, Park GH, Go MJ, Lee J, Lee BY. Preparation of [bis(amido)-phosphine] and [amido-phosphine sulfide or oxide] hafnium and zirconium complexes for olefin polymerization. J Organomet Chem 2014. [DOI: 10.1016/j.jorganchem.2014.09.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Park JH, Jang YE, Jeon JY, Go MJ, Lee J, Kim SK, Lee SI, Lee BY. Preparation of ansa-metallocenes for production of poly(α-olefin) lubricants. Dalton Trans 2014; 43:10132-8. [PMID: 24875269 DOI: 10.1039/c4dt00997e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An ansa-zirconocene bearing methyl substituents at all positions adjacent to the bridgehead [(-C(Ph)HC(Ph)H-)(η(5)-2,5-Me2C5H2)2ZrCl2] (4) was prepared in high yields (78%) through the reductive dimerization of 1,4-dimethyl-6-phenylfulvene utilizing ZrCl2·DME generated in situ. The structure of 4 was subsequently confirmed using X-ray crystallography. 4 exhibited excellent catalytic performance with regard to 1-decene oligomerization, which was carried out with the intention of preparing lubricant base stocks. High activities (21 × 10(6) g mol(-1) Zr h(-1) activity; TON = 150 000; TOF = 42 s(-1)) were observed at temperatures as high as 120 °C and the oligomer distribution was appropriate for lubricant application. The simulated distillation (SIMDIS) data confirmed that a wide range of oligomers were formed, ranging from the dimer (2-mer) to 20-mer. A minimal amount of the dimer and oligomers larger than the 10-mer was formed (13 and 25 wt%, respectively). Alternatively, a typical unbridged complex such as (η(5)-nBuC5H4)2ZrCl2 primarily produced dimers (54 wt%), whereas the ansa-zirconocene (EBI)ZrCl2 primarily produced oligomers larger than 10-mer (62 wt%). The methyl substituents at the positions adjacent to the bridgehead in 4 played a significant role in the catalytic performance.
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Affiliation(s)
- Ji Hae Park
- Department of Molecular Science and Technology, Ajou University, Suwon 443-749, South Korea.
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