Takeshi Shiono

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Organization: Hiroshima University

Department: Department of Applied Chemistry, Graduate School of Engineering

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Block Copolymer Coordination Polymer

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References

Highly Robust Nickel Catalysts Containing Anilinonaphthoquinone Ligand for Copolymerization of Ethylene and Polar Monomers

Co-reporter:Xia Fu, Lingjun Zhang, Ryo Tanaka, Takeshi Shiono, and Zhengguo Cai

Macromolecules December 12, 2017 Volume 50(Issue 23) pp:9216-9216

Publication Date(Web):November 17, 2017

DOI:10.1021/acs.macromol.7b01947

Copolymerizations of ethylene with polar monomers such as 5-hexene-1-yl acetate and allyl acetate are explored using nickel complexes bearing a class of anilinonaphthoquinone ligands. High tolerability of this complex toward polar comonomer is achieved by the installation of sterically bulky substituent on the aniline ligand. Moreover, the heterogenization of the nickel complexes using silica-supported modified methylaluminoxane enhances the copolymerization performances. The catalyst is highly active and thermally stabile to give semicrystalline ester-functionalized high molecular weight polyethylenes.

Living polymerization of higher 2-alkene with α-diimine nickel catalysts: Synthesis and characterization of high molecular weight poly(2-alkene)s

Co-reporter:Fuzhou Wang, Ryo Tanaka, Zhengguo Cai, Yuushou Nakayama, Takeshi Shiono

Polymer 2017 Volume 127(Volume 127) pp:

Publication Date(Web):3 October 2017

DOI:10.1016/j.polymer.2017.08.050

•Polymerization of 2-pentene, 2-hexene and 2-octene was achieved by α-diimine nickel complexes activated by MAO.•Living polymerization of 2-alkene proceeded at 0 °C.•Poly(2-alkene)s possessed methyl, ethyl, Cω-3, Cω-2 branches and a small amount of 1,ω-enchainment via monomer-isomerization.A series of higher 2-alkenes, i.e., 2-pentene, 2-hexene and 2-octene were polymerized with phenyl substituted α-diimine nickel complexes in combination with modified methylaluminoxane (MMAO) to produce branched poly(2-alkene)s with high molecular weight and narrow molecular weight distribution (Mw/Mn < 1.8). At 0 °C, these 2-alkenes polymerized in a living manner to produce amorphous polymers with glass transition temperature of –70 ∼ –65 °C. The microstructures of the produced polymers indicated the 2,3- and 3,2-insertion followed by chain-walking and the incorporation of a small amount of 1-alkene formed by isomerization. The branch structures were significantly depended on the polymerization temperature, and the ratio of methyl branch predominantly derived from 3,2-insertion was increased with increasing the polymerization temperature.Download high-res image (216KB)Download full-size image

Precision Chain-Walking Polymerization of trans-4-Octene Catalyzed by -Diimine Nickel(II) Catalysts Bearing ortho-sec-Phenethyl Groups

Co-reporter:Fuzhou Wang;Ryo Tanaka;Zhengguo Cai;Yuushou Nakayama

Macromolecular Rapid Communications 2016 Volume 37( Issue 16) pp:1375-1381

Publication Date(Web):

DOI:10.1002/marc.201600203

Facile Synthesis of Novel Polyethylene-Based A-B-C Block Copolymers Containing Poly(methyl methacrylate) Using a Living Polymerization System

Co-reporter:Xiangyang Song;Qiong Ma;Zhengguo Cai;Ryo Tanaka;Robert B. Grubbs

Macromolecular Rapid Communications 2016 Volume 37( Issue 3) pp:227-231

Publication Date(Web):

DOI:10.1002/marc.201500614

Structure-stereospecificity relationships of propylene polymerization using substituted ansa-silylene(fluorenyl)(amido) titanium complexes

Co-reporter:Ryo Tanaka, Chie Yanase, Zhengguo Cai, Yuushou Nakayama, Takeshi Shiono

Journal of Organometallic Chemistry 2016 Volume 804() pp:95-100

Publication Date(Web):15 February 2016

DOI:10.1016/j.jorganchem.2015.12.028

•New ansa-Fluorenylamidotitanium complexes with various substituents were synthesized.•The complexes promoted syn-specific of aspecific propylene polymerization.•The origin of the stereodefect in this polymerization system was revealed.ansa-Fluorenylamidotitanium complexes bearing various substituents on the nitrogen and fluorene (2a-d) were synthesized. The structures of the complexes were characterized by 1H and 13C NMR, and X-ray crystal analyses were performed for complexes 2a, 2b and 2d. The coordination mode of the fluorenyl group to the metal center was changed from η3 to η1 when a bulky group was introduced on the nitrogen or 2,3-position of the fluorenyl ring. Syndiotactic-specificity of the catalyst for the propylene polymerization was reduced when bulky group was introduced on the nitrogen. Least-square fitting analysis of the steric pentad distributions revealed that the stereodefect was mainly formed by the chain migration without monomer insertion, which is accelerated by the η1-coordination of the fluorenyl group.ansaFluorenylamidotitanium complexes bearing various substituents on the nitrogen and fluorene were synthesized to reveal the relationship between the structure and stereospecificity of propylene polymerization. Syndiotactic-specificity of the catalyst for the propylene polymerization was reduced when bulky group was introduced on the nitrogen.

The preparation of boron-containing aluminoxanes and their application as cocatalysts in the polymerization of olefins

Co-reporter:Ryo Tanaka, Takaaki Hirose, Yuushou Nakayama and Takeshi Shiono

Polymer Journal 2016 48(1) pp:67-71

Publication Date(Web):September 30, 2015

DOI:10.1038/pj.2015.81

Boron-moiety-containing aluminoxanes (BMAOs) were prepared from the partial protonolysis of Me3Al using various arylboronic acids. Compared with methylaluminoxane (MAO) generated from the hydrolysis of Me3Al, BMAO prepared from C6F5B(OH)2 and Me3Al induced a higher activity at the same Al/Ti ratio in the Ti-based olefin polymerization catalyst (ansa-Me2Si(Flu)(NtBu)TiMe2; 5). The time course of propylene consumption when using BMAO showed the deactivation of the catalyst, whereas the 5–dMAO system promoted a living polymerization. Among the BMAOs, only those derived from arylboronic acids with electron-withdrawing groups were observed to act as efficient cocatalysts.

Theoretical investigation of the mechanism of syndiospecific propylene polymerization using ansa-dimethylsilylene(fluorenyl)(amido)titanium complexes

Co-reporter:Ryo Tanaka, Yuushou Nakayama, Takeshi Shiono

Journal of Organometallic Chemistry 2016 Volume 823() pp:112-115

Publication Date(Web):15 November 2016

DOI:10.1016/j.jorganchem.2016.09.022

•In silico study on the polymerization using fluorenylamidotitanium complex was performed.•Propylene coordinated to the Ti center avoiding the steric repulsion of polymer chain.•The mechanism of stereodefect formation derived from bulky amido group was revealed.Theoretical study on the propylene polymerization using ansa-dimethylsilylene(fluorenyl)(amido)dimethyltitanium complexes were performed and related to the experimental results. The calculated activation energies for coordination-insertion of propylene via four different conformations after the first monomer insertion showed that propylene coordinates to the titanium center avoiding the steric repulsion of polymer chain, which was placed toward the amido group. The bulkiness of the amido groups was closely related to the frequency of the chain-migration without monomer insertion, probably because the bulky amido group would force the fluorenyl ligand to coordinate to the titanium center in η1-manner. These theoretical results well explained the experimental ones.Theoretical study on the propylene polymerization using ansa-dimethylsilylene(fluorenyl)(amido)dimethyltitanium complexes were performed and related to the experimental results. The formation of stereodefect was well explained by the steric effect of bulky amido group.

Room-temperature SuzukiMiyaura cross-coupling reaction with -diimine Pd(II) catalysts

Co-reporter:Fuzhou Wang;Ryo Tanaka;Zhengguo Cai;Yuushou Nakayama

Applied Organometallic Chemistry 2015 Volume 29( Issue 11) pp:771-776

Publication Date(Web):

DOI:10.1002/aoc.3365

An α-diimine Pd(II) complex containing chiral sec-phenethyl groups, {bis[N,N′-(4-methyl-2-sec-phenethylphenyl)imino]-2,3-butadiene}dichloropalladium (rac-C1), was synthesized and characterized. rac-C1 was applied as an efficient catalyst for the Suzuki–Miyaura cross-coupling reaction between various aniline halides and arylboronic acid in PEG-400–H₂O at room temperature. Among a series of aniline halides, rac-C1 did not catalyze the cross-coupling of aniline chlorides and fluorides but efficiently catalyzed the cross-coupling of aniline bromides and iodides with phenylboronic acid. The catalytic activity reduced slightly with increasing steric hindrance of the aniline bromides. The complexes {bis[N,N′-(4-fluoro-2,6-diphenylphenyl)imino]-2,3-butadiene}dichloropalladium and {bis[N,N′-(4-fluoro-2,6-diphenylphenyl)imino]acenaphthene}dichloropalladium were also found to be efficient catalysts for the reaction. Copyright © 2015 John Wiley & Sons, Ltd.

Synthesis and application of α-diimine Ni(II) and Pd(II) complexes with bulky steric groups to polymerization of ethylene and methyl methacrylate

Co-reporter:Fuzhou Wang, Ryo Tanaka, Qingshan Li, Yuushou Nakayama, Jianchao Yuan, Takeshi Shiono

Journal of Molecular Catalysis A: Chemical 2015 Volume 398() pp:231-240

Publication Date(Web):March 2015

DOI:10.1016/j.molcata.2014.11.004

•A series of α-diimine ligands bearing bulky groups and their Ni(II) and Pd(II) complexes were synthesized.•Ligand steric and electronic effects on α-diimine Ni(II)/Pd(II) catalysts for ethylene/MMA polymerization.•Highly active nickel precatalysts and highly branched polyethylenes.•High conversion rates and syndiotactic-rich PMMAs.A series of α-diimine Ni(II) and Pd(II) complexes containing bulky steric groups, {[(4-R-2,6-Ph2C6H2NC)2Nap]MX2} (Nap: 1,8-naphthdiyl, MX2 = NiBr2, R = F (4a); R = Cl (4b); R = Me (4c); R = n-Bu (4d) and MX2 = PdCl2, R = F (5a); R = Cl, (5b); R = Me (5c); R = n-Bu (5d)), {[4-F-2,6-Ph2C6H2NC(Me)]2PdCl2}(5e), were synthesized and characterized. The crystal structures of ligands 3d, 3e and complexes 4a, 4b, 5a, 5b, 5e were determined by X-ray crystallography. These complexes, when activated with diethylaluminum chloride (DEAC), were used to catalyze polymerization of ethylene and methyl methacrylate (MMA) under mild conditions. The introduction of an electron-withdrawing group to the ligand framework improves the catalytic activity significantly. The Ni(II) catalysts 4a–d exhibited high catalytic activity in the polymerization of ethylene (up to106 g PE/(mol Ni h bar)) and produced highly branched polyethylenes at high temperature. Interestingly, complex 4a could produce syndiotactic-rich PMMAs at low temperature (0 °C, up to 77.2% of rr triads).

Ethylenepropylene copolymerization behavior of ansa-dimethylsilylene(fluorenyl)(amido)dimethyltitanium complex: Application to ethylenepropylenediene or ethylenepropylenenorbornene terpolymers

Co-reporter:Ryo Tanaka;Issei Kamei;Zhengguo Cai;Yuushou Nakayama

Journal of Polymer Science Part A: Polymer Chemistry 2015 Volume 53( Issue 5) pp:685-691

Publication Date(Web):

DOI:10.1002/pola.27494

ABSTRACT

Copolymerization behavior of ethylene (E) and propylene (P) using ansa-dimethylsilylene(fluorenyl)(amido)dimethyltitanium complex was investigated. P was more reactive than E regardless of the chain-end monomer unit, which was very unusual in the coordination polymerization system. The terpolymerizations of E, P and norbornene (NB) or 5-ethylidene-2-norbornene (5E2N) were also performed. The each content in the E/P/NB terpolymer was independently controlled by the initial concentration of NB and E/P feed ratio. Glass transition temperature (T_g) of the terpolymer was raised in proportion to the NB content and close to that of the corresponding NB/E random copolymer with the same NB content. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 685–691

Pseudo-living copolymerization of norbornene and ω-alkenylborane – Synthesis of monodisperse functionalized cycloolefin copolymer

Co-reporter:Ryo Tanaka, Tomomi Ikeda, Yuushou Nakayama, Takeshi Shiono

Polymer 2015 Volume 56() pp:218-222

Publication Date(Web):15 January 2015

DOI:10.1016/j.polymer.2014.11.059

The synthesis of norbornene copolymer with hydroxy groups was performed by the copolymerization of norbornene (NB) with 9-(7-octenyl)-borabicyclo[3.3.1]nonane (OctBBN) using ansa-dimethylsilyl(fluorenyl)(amido)titanium catalyst (1) activated by Ph3CB(C6F5)4 and successive oxidation. The glass transition temperature (Tg) of the copolymer was higher than the polymer with the same hydroxy group content synthesized by the copolymerization of NB and ω-alkenylaluminum. The 13C NMR spectrum of the copolymer clearly showed that alkylborane moiety was converted quantitatively to hydroxy groups. Copolymerization of NB and OctBBN by the 1-MMAO/BHT system proceeded in a pseudo-living manner without chain transfer reaction.

New nickel(II) diimine complexes bearing phenyl and sec-phenethyl groups: synthesis, characterization and ethylene polymerization behaviour

Co-reporter:Fuzhou Wang;Jianchao Yuan;Qingshan Li;Ryo Tanaka;Yuushou Nakayama

Applied Organometallic Chemistry 2014 Volume 28( Issue 7) pp:477-483

Publication Date(Web):

DOI:10.1002/aoc.3151

A series of nickel(II) catalysts containing phenyl and chiral sec-phenethyl groups, {[(4-R₁-2-R₂C₆H₂NC)₂Nap]NiBr₂} (Nap: 1,8-naphthdiyl, R₁ = Me, R₂ = Ph (3a); R₁ = Me, R₂ = sec-phenethyl (3b); R₁ = Cl, R₂ = sec-phenethyl (3c); R₁ = Me, R₂ = Me (3d) were synthesized and characterized. All organic compounds were fully characterized by FT-IR and NMR spectroscopy and elemental analysis. The single crystal for X-ray crystallography was isolated from 3a in CH₂Cl₂/n-hexane under air; the crystal structure showed a binuclear complex 3a′, in which each nickel atom was six-coordinate. The two nickel atoms together with two bromine atoms form a planar four-membered ring, with a bromine and H₂O axial ligands. These complexes, activated by diethylaluminum chloride and chiral nickel pre-catalysts rac-3c, exhibited good activities (up to 2.85 × 10⁶ g PE (mol Ni h bar)⁻¹) for ethylene polymerization, and produced polyethylene products with a high degree of branching (up to 117 branched per 1000 carbons) at high temperature. The type and amount of branches of the polyethylenes obtained were determined by ¹H and ¹³C NMR spectroscopy. Copyright © 2014 John Wiley & Sons, Ltd.

Heterogenization of an Anilinonaphthoquinone-Chelated Nickel Complex for Ethylene Polymerization Using Silica-Supported Modified Methylaluminoxane

Co-reporter:Mitsuhiro Okada;Yuushou Nakayama

Macromolecular Chemistry and Physics 2014 Volume 215( Issue 18) pp:1792-1796

Publication Date(Web):

DOI:10.1002/macp.201400165

Synthesis of a Multiblock Copolymer of cis-1,4-Polybutadiene and Poly(3-buten-1-ol)

Co-reporter:Ryo Tanaka;Yuki Kasai;Masahito Shinzawa;Zhengguo Cai;Yuushou Nakayama

Macromolecular Chemistry and Physics 2014 Volume 215( Issue 9) pp:888-892

Publication Date(Web):

DOI:10.1002/macp.201400016

Synthesis and thermal, mechanical, and optical properties of ABA or AB block copolymers containing poly(norbornene-co-1-octene)

Co-reporter:Ryo Tanaka;Takuya Suenaga;Zhengguo Cai;Yuushou Nakayama

Journal of Polymer Science Part A: Polymer Chemistry 2014 Volume 52( Issue 2) pp:267-271

Publication Date(Web):

DOI:10.1002/pola.26999

ABSTRACT

A–B–A block copolymers which consist of poly(norbornene-co-1-octene) and atactic polypropylene (PP) segments were synthesized by using ansa-fluorenylamidotitanium complex as a catalyst varying the ratio of norbornene, 1-octene, and propylene. The copolymer was obtained quantitatively with high molecular weight (>100,000) and narrow molecular weight distribution (polydispersity index, <1.5). A–B block copolymers of poly(norbornene-co-1-octene) and poly(methyl methacrylate) (PMMA) was also obtained by the same procedure. Mechanical and optical properties of these copolymer films, which were obtained by solution casting process, were also investigated. Introduction of PP soft segment greatly improved mechanical properties, keeping their high transparency. Introduction of PMMA block also increased the tensile strength. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 267–271

Synthesis of high-molecular weight block copolymers of norbornene and propylene with methyl methacrylate initiated by a fluorenylamido titanium complex

Co-reporter:Ryo Tanaka, Yuushou Nakayama and Takeshi Shiono

Polymer Chemistry 2013 vol. 4(Issue 14) pp:3974-3980

Publication Date(Web):03 May 2013

DOI:10.1039/C3PY00400G

Synthesis of a norbornene–propylene–methyl methacrylate (MMA) block terpolymer was achieved using a fluorenylamide-ligated titanium complex for the first time. Unlike other block copolymerization examples of olefins and MMA, the second MMA polymerization required an additional aluminium compound, indicating that the carbonyl group of MMA was activated only by aluminium Lewis acid. Polymerization reactions of propylene and MMA both proceeded in a syndiotactic-specific manner.

Modification effect of spherical zirconia with SiCl4 as a support of methylaluminoxane for heterogeneous single-site catalyst

Co-reporter:Sasiradee Jantasee, Bunjerd Jongsomjit, Haruki Yano, Takeshi Shiono

European Polymer Journal 2013 Volume 49(Issue 12) pp:4195-4200

Publication Date(Web):December 2013

DOI:10.1016/j.eurpolymj.2013.09.030

•Methylaluminoxane was supported on ZrO2 unmodified and modified with SiCl4.•The supported cocatalysts were applied for living polymerization of propylene.•The modification effect with SiCl4 was clarified by using the living character.•The catalysts also conducted controlled copolymerization of ethylene and 1-hexene.Unmodified and SiCl4-modified spherical zirconia-supported methylaluminoxane were used as cocatalyst for propylene polymerization as well as ethylene/1-hexene copolymerization in combined with Me2Si(η3-C13H8)(η1-NtBu)TiMe2 (1) at 0 °C. The modification with SiCl4 improved the catalytic activity. The improvement was clearer in ethylene/1-hexene copolymerization than in propylene polymerization. The number average molecular weight (Mn) of polypropylenes increased linearly against the polymerization time regardless the cocatalyst used to give polymers with narrow molecular weight distribution (Mw/Mn < 1.32), indicating the living nature of the catalytic systems. Thus, propagation rate constant (kp) and the number of active centers (C*) were evaluated from Mn and the number of polymer-chains. When the zirconia was modified with SiCl4, the kp value decreased and the C* increased. The latter effect was more significant to enhance the catalytic activity.Graphical abstract.

Copolymerization of Ethylene and 1-Hexene with Ansa-Dimethylsilylene(fluorenyl) (t-butylamido)Dimethyltitanium Complexes Activated by Modified Methylaluminoxane

Co-reporter:Mingkwan Wannaborworn;Piyasan Praserthdam;Bunjerd Jongsomjit;Zhengguo Cai;Haruki Yano

Macromolecular Chemistry and Physics 2013 Volume 214( Issue 22) pp:2584-2590

Publication Date(Web):

DOI:10.1002/macp.201300446

Facile Synthesis of Hydroxy-Functionalized Cycloolefin Copolymer Using -Alkenylaluminium as a Comonomer

Co-reporter:Takeshi Shiono;Mitsunori Sugimoto;Tariqul Hasan;Zhengguol Cai

Macromolecular Chemistry and Physics 2013 Volume 214( Issue 19) pp:2239-2244

Publication Date(Web):

DOI:10.1002/macp.201300347

Copolymerization of ethylene with 1,1-disubstituted olefins catalyzed by ansa-(fluorenyl)(cyclododecylamido)dimethyltitanium complexes

Co-reporter:Yuushou Nakayama;Yuuichi Sogo;Zhengguo Cai

Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 5) pp:1223-1229

Publication Date(Web):

DOI:10.1002/pola.26491

Abstract

A series of titanium complexes with ansa-(fluorenyl)(cyclododecylamido) ligands, Me₂Si(η³-R)(N-c-C₁₂H₂₃)TiMe₂ [R = fluorenyl (5), 2,7-^tBu₂fluorenyl (6), 3,6-^tBu₂fluorenyl (7)], was synthesized. The crystal structure of complex 6 revealed η³-coordination of the fluorenyl moiety to the metal. Upon activation with trialkylaluminum-free modified methylaluminoxane, complexes 5–7 as well as the corresponding ^tBu amide complexes, Me₂Si(η³-R)(N^tBu)TiMe₂ [R = fluorenyl (2), 2,7-^tBu₂fluorenyl (3), 3,6-^tBu₂fluorenyl (4)], were adopted as the catalysts for the copolymerization of ethylene (E) and isobutylene (IB). Among these complexes, complex 6 was found to achieve the highest IB incorporation to produce alternating E-IB copolymers. Complex 6 system also achieved copolymerization of E and limonene. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Copolymerization of norbornene with -alkenylaluminum as a precursor comonomer for introduction of carbonyl moieties

Co-reporter:Jang-Woo Lee;Sasiradee Jantasee;Bunjerd Jongsomsjit;Ryo Tanaka;Yuushou Nakayama

Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 23) pp:5085-5090

Publication Date(Web):

DOI:10.1002/pola.26940

ABSTRACT

Norbornene copolymers functionalized with methyl ester group or carboxy group are facilely synthesized by the copolymerization of norbornene and 7-octenyldiisobutylaluminum (ODIBA) with ansa-dimethylsilylene(fluorenyl)(t-butylamido)dimethyltitanium (1) activated by Ph₃CB(C₆F₅)₄, and the sequential CO₂/methanolysis reactions or CO₂/hydrolysis reactions, respectively. The methanolysis and the hydrolysis are simply switched by engaging acidic methanol or acidic aqueous acetone as the quenching/washing solution, respectively. Meanwhile, the increase of ODIBA in the copolymerization abruptly decreases the yield and number–average molecular weight (M_n) of the product. However, the addition of triisobutylaluminum (8 mM) and the use of excess Ph₃CB(C₆F₅)₄ (twofold of 0.4 mM of 1) significantly increase the yield, accompanying the increase in the M_n and the narrowing of the molecular weight distribution (M_w/M_n), especially in the case of the use of excess Ph₃CB(C₆F₅)₄. The yield (g polymer/g monomers), M_n, and M_w/M_n reach up to 0.82, 341,000, and 1.46, respectively, at a copolymerization condition. The carboxy groups in the norbornene copolymers are controlled in the range of 0–1.8 mol % in high polymer yields with high M_n and narrow M_w/M_n accompanied by the decrease in the contact angle with water from 104° to 89°. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5085–5090

Precise synthesis of olefin block copolymers using a syndiospecific living polymerization system

Co-reporter:Zheng-guo Cai 蔡正国;Hai-hui Su

Chinese Journal of Polymer Science 2013 Volume 31( Issue 4) pp:541-549

Publication Date(Web):2013 April

DOI:10.1007/s10118-013-1250-7

This feature article summarizes the synthesis of novel olefin block copolymers using fast syndiospecific living homo- and copolymerization of propylene, higher 1-alkene, and norbornene with ansa-fluorenylamidodimethyltitaniumbased catalyst according to the authors’ recent results. The catalytic synthesis of monodisperse polyolefin and olefin block copolymer was also described using this living system.

Living polymerization of olefins with ansa-dimethylsilylene(fluorenyl)(amido)dimethyltitanium-based catalysts

Co-reporter:Takeshi Shiono

Polymer Journal 2011 43(4) pp:331-351

Publication Date(Web):2011-04-01

DOI:10.1038/pj.2011.13

This article reviews the living homopolymerization and copolymerization of propene, 1-alkene and norbornene with ansa-dimethysilylene(fluorenyl)(amido)dimethyltitanium, Me2Si(η3-C13H8)(η1-NtBu)TiMe2 and its derivatives, correlating the effects of cocatalysts, solvents, polymerization conditions and the substituents of the fluorenyl ligand with catalytic features, such as livingness, initiation efficiency, propagation rate, syndiospecificity and copolymerization ability. The synthesis of novel olefin block copolymers and their catalytic synthesis are also introduced using this living system.

Efficient Molecular Weight Control with Trialkylaluminum in Ethylene/Norbornene Copolymerization by [Ph2C(Flu)(3-MeCp)]ZrCl2/Methylaluminoxane Catalyst

Co-reporter:Tomoyuki Tada;Zhengguo Cai;Yuushou Nakayama

Macromolecular Chemistry and Physics 2010 Volume 211( Issue 19) pp:2132-2137

Publication Date(Web):

DOI:10.1002/macp.201000172

Additive effects of alkylaluminium compounds on propylene-1,3-butadiene copolymerization using isospecific zirconocene catalysts

Co-reporter:Takeshi Ishihara, Hoang The Ban, Hideaki Hagihara, Takeshi Shiono

Journal of Organometallic Chemistry 2010 695(12–13) pp: 1694-1699

Publication Date(Web):

DOI:10.1016/j.jorganchem.2010.04.003

Highly Active Living Random Copolymerization of Norbornene and 1-Alkene with ansa-Fluorenylamidodimethyltitanium Derivative: Substituent Effects on Fluorenyl Ligand

Co-reporter:Zhengguo Cai, Ryotaro Harada, Yuushou Nakayama and Takeshi Shiono

Macromolecules 2010 Volume 43(Issue 10) pp:4527-4531

Publication Date(Web):April 23, 2010

DOI:10.1021/ma1006107

Copolymerizations of norbornene with propylene and 1-octene were conducted with a series of ansa-fluorenylamidodimethyltitanium complexes, [t-BuNSiMe2Flu]TiMe2 (1), [t-BuNSiMe2(3,6-tBu2Flu)]TiMe2 (2), [t-BuNSiMe2(2,7-tBu2Flu)]TiMe2 (3), and [t-BuNSiMe2(C29H36)]TiMe2 (4; C29H36, octamethyloctahydrodibenzofluorenyl), activated by trialkylaluminum-free modified methylaluminoxane. The catalytic systems promoted random copolymerizations in a living manner regardless of the titanium complex used. The activity increased by the introduction of the tBu groups on the Flu ligand, and 4 showed the highest activity for each copolymerization. The comonomer content of the copolymers obtained was controllable in a wide range by changing comonomer feed ratio with these catalytic systems. The linear relationships were observed between the norbornene content and the glass transition temperature of the copolymer, whereas the slopes depended on the titanium complex used. The result suggested that the titanium complexes affected the microstructures of the copolymers produced. The evaluation of the monomer reactivity ratios in the copolymerization of norbornene with 1-octene indicates a preference for the norbornene insertion regardless of the last inserted monomer unit in growing polymer chain in all the catalytic systems.

Synthesis of stereoblock polypropylene by change of temperature in living polymerization

Co-reporter:Zhengguo Cai;Yuushou Nakayama

Macromolecular Research 2010 Volume 18( Issue 8) pp:737-741

Publication Date(Web):2010 August

DOI:10.1007/s13233-010-0813-5

Highly Active Syndiospecific Living Polymerization of Higher 1-Alkene with ansa-Fluorenylamidodimethyltitanium Complex

Co-reporter:Zhengguo Cai;Masayoshi Ohmagari;Yuushou Nakayama

Macromolecular Rapid Communications 2009 Volume 30( Issue 21) pp:1812-1816

Publication Date(Web):

DOI:10.1002/marc.200900413

Macromol. Rapid Commun. 21/2009

Co-reporter:Zhengguo Cai;Masayoshi Ohmagari;Yuushou Nakayama

Macromolecular Rapid Communications 2009 Volume 30( Issue 21) pp:

Publication Date(Web):

DOI:10.1002/marc.200990053

A Highly Active Catalyst Composed of ansa-Fluorenylamidodimethyltitanium Derivative for Propene Polymerization

Co-reporter:Takeshi Shiono;Ryotaro Harada;Zhengguo Cai;Yuushou Nakayama

Topics in Catalysis 2009 Volume 52( Issue 6-7) pp:675-680

Publication Date(Web):2009 June

DOI:10.1007/s11244-009-9215-3

Me2Si(C29H36)(NtBu)TiMe2 (4; C29H36, octamethyloctahydrodibenzofluorenyl) was synthesized and characterized by elemental analysis, 1H NMR and single crystal X-ray analysis. The complex was applied for propene polymerization using dried modified methylaluminoxane (dMMAO) as a cocatalyst at 0 °C by a semi-batch method. The catalytic system showed the activity of 11,400 kg-polymer mol-Ti−1 h−1, which was too high to control the polymerization. Batch-wise polymerizations were then conducted by changing the amount of propene in feed. The polymerizations proceeded quantitatively, and the number-average molecular weight increased linearly against the polymer yield with keeping the number of polymer chains constant although the polydispersity indices were broader than that expected in a living polymerization. The results of postpolymerization indicated the smooth chain transfer after the monomer consumption.

Synthesis of Regioblock Polybutadiene with CoCl2-Based Catalyst via Reversible Coordination of Lewis Base

Co-reporter:Zhengguo Cai, Masahito Shinzawa, Yuushou Nakayama and Takeshi Shiono

Macromolecules 2009 Volume 42(Issue 20) pp:7642-7643

Publication Date(Web):September 30, 2009

DOI:10.1021/ma901886b

Catalytic Synthesis of a Monodisperse Olefin Block Copolymer Using a Living Polymerization System

Co-reporter:Zhengguo Cai;Yuushou Nakayama

Macromolecular Rapid Communications 2008 Volume 29( Issue 6) pp:525-529

Publication Date(Web):

DOI:10.1002/marc.200700687

Facile Synthesis of Tailor-Made Stereoblock Polypropylenes via Successive Variation of Monomer Pressure

Co-reporter:Zhengguo Cai, Yuushou Nakayama and Takeshi Shiono

Macromolecules 2008 Volume 41(Issue 17) pp:6596-6598

Publication Date(Web):August 16, 2008

DOI:10.1021/ma801318u

Random Copolymerization of Norbornene with Higher 1-Alkene with ansa-Fluorenylamidodimethyltitanium Catalyst

Co-reporter:Takeshi Shiono, Mitsunori Sugimoto, Tariqul Hasan, Zhengguo Cai and Tomiki Ikeda

Macromolecules 2008 Volume 41(Issue 22) pp:8292-8294

Publication Date(Web):October 21, 2008

DOI:10.1021/ma802119d

Synthesis and characterization of norbornene–ethylene–styrene terpolymers with a substituted ansa-fluorenylamidodimethyltitanium-based catalyst

Co-reporter:Hoang The Ban;Kei Nishii;Yasuo Tsunogae

Journal of Polymer Science Part A: Polymer Chemistry 2007 Volume 45(Issue 13) pp:2765-2773

Publication Date(Web):18 MAY 2007

DOI:10.1002/pola.22033

This article reports a synthetic method for a norbornene–ethylene–styrene (N-E-S) terpolymer, which has not been well investigated so far, via incorporation of styrene (S) into vinyl-type norbornene–ethylene (N-E) copolymers catalyzed by a substituted ansa-fluorenylamidodimethyltitanium [Me₂Si(3,6-tBu₂Flu)(tBuN)]TiMe₂ catalyst (I) activated with a [Ph₃C][B(C₆F₅)₄]/Al(iBu)₃ cocatalyst at room temperature in toluene. The resulting terpolymerization product contained the targeted N-E-S terpolymer and the contaminated homopolymers, which were then able to be completely removed by solvent fractionation techniques. While homopolystyrene was easily extracted by fractionation with methylethylketone as a soluble part, homopolyethylene and a trace amount of homopolynorbornene could be perfectly separated by fractionation with chloroform as insoluble parts. The detail characterizations of a chloroform-soluble polymer with gel permeation chromatography, nuclear magnetic resonance, and differential scanning calorimetry analyses proved that it contained a true N-E-S terpolymer with long N-E sequences incorporated with isolated or short styrene sequences. The homogeneity of the morphology together with a single glass transition temperature that proportionally decreased with the increase of the styrene contents indicated that the N-E-S terpolymer obtained in this work is a random polymer with an amorphous structure. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2765–2773, 2007

Homo- and copolymerization of norbornene derivatives with ethene by ansa-fluorenylamidodimethyltitanium activated with methylaluminoxane

Co-reporter:Tariqul Hasan;Tomiki Ikeda

Journal of Polymer Science Part A: Polymer Chemistry 2007 Volume 45(Issue 20) pp:4581-4587

Publication Date(Web):29 AUG 2007

DOI:10.1002/pola.22193

(t-BuNSiMe₂Flu)TiMe₂ (1) activated with Me₃Al-free methylaluminoxane (dried MAO) which conducts vinyl addition polymerization of norbornene (N) with very high activity was applied for homopolymerization of N derivatives (i.e., 5-vinyl-2-norbornene (5V2N), 5-ethylidene-2-norbornene (5E2N), dicyclopentadiene (DCPD)) at 40 °C. The activities for the N derivatives were about two orders of magnitude lower than that for N and decreased in the following order: 5E2N ≫ 5V2N ≫ DCPD. Copolymerization of ethene (E) and 5E2N under an atmospheric pressure of E was then conducted by 1-dried MAO. The copolymerization proceeded with better activity than the homopolymerization of 5E2N and gave poly(E-co-5E2N) with narrow molecular weight distribution. The content of the ethylidene group in poly(E-co-5E2N) was controlled by the feed ratio of 5E2N/E. The T_g value of the copolymer changed from 70 °C to 155 °C according to the 5E2N content from 27 mol % to 68 mol %. The addition of N as a third monomer to the E-5E2N copolymerization improved the activity and raised the T_g values of the terpolymer above 200 °C. The content of 5E2N was controlled by the 5E2N/N ratio with keeping the high T_g values. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4581–4587, 2007

Copolymerization of propylene with 1,3-butadiene using isospecific zirconocene catalysts

Co-reporter:Takeshi Ishihara;Hoang The Ban;Hideaki Hagihara

Journal of Polymer Science Part A: Polymer Chemistry 2007 Volume 45(Issue 24) pp:5731-5740

Publication Date(Web):30 OCT 2007

DOI:10.1002/pola.22321

Poly(propylene-ran-1,3-butadiene) was synthesized using isospecific zirconocene catalysts and converted to telechelic isotactic polypropylene by metathesis degradation with ethylene. The copolymers obtained with isospecific C₂-symmetric zirconocene catalysts activated with modified methylaluminoxane (MMAO) had 1,4-inserted butadiene units (1,4-BD) and 1,2-inserted units (1,2-BD) in the isotactic polypropylene chain. The selectivity of butadiene towards 1,4-BD incorporation was high up to 95% using rac-dimethylsilylbis(1-indenyl)zirconium dichloride (Cat-A)/MMAO. The molar ratio of propylene to butadiene in the feed regulated the number-average molecular weight (M_n) and the butadiene contents of the polymer produced. Metathesis degradations of the copolymer with ethylene were conducted with a WCI₆/SnMe₄/propyl acetate catalyst system. The ¹H NMR spectra before and after the degradation indicated that the polymers degraded by ethylene had vinyl groups at both chain ends in high selectivity. The analysis of the chain scission products clarified the chain end structures of the poly(propylene-ran-1,3-butadiene). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5731–5740, 2007

Synthesis of Uniquely Branched Polyethylene by Anilinonaphthoquinone Ligated Nickel Complex Activated with Tris(pentafluorophenyl)borane

Co-reporter:Tomiki Ikeda;Mitsuhiro Okada;Yuushou Nakayama

Macromolecular Rapid Communications 2006 Volume 27(Issue 17) pp:1418-1423

Publication Date(Web):24 AUG 2006

DOI:10.1002/marc.200600335

Summary: A novel nickel complex ligated with 2-(2,6-diisopropylanilino)-1,4-naphthoquinone (1) was synthesized. The molecular structure of 1 determined by X-ray analysis was a square-planar geometry. Complex 1 conducted ethylene polymerization at 40 °C in a low activity to give linear polyethylene. On the other hand, 1 activated with 4 eq. of B(C₆F₅)₃ was highly active for ethylene polymerization and gave a polymer possessing short chain branches of methyl, ethyl and propyl groups formed by a chain walking mechanism, as well as long chain branches, of which the content was almost the same as the total content of short chain branches. These results suggest that the macromonomer formed via β-hydride elimination should have effectively copolymerized with ethylene to give the long chain branches in the B(C₆F₅)₃-activated system.

Polymerization of propylene with [t-BuNSiMe2Ind]TiMe2–MAO catalyst systems

Co-reporter:Kei Nishii, Tomiki Ikeda, Munetaka Akita, Takeshi Shiono

Journal of Molecular Catalysis A: Chemical 2005 Volume 231(1–2) pp:241-246

Publication Date(Web):20 April 2005

DOI:10.1016/j.molcata.2004.12.035

ansa-Indenylamidodimethyltitanium complex ([t-BuNSiMe2Ind]TiMe2: 1) was synthesized by one-pot reactions starting from the ligand, MeLi and TiCl4. The structure of 1 was determined by X-ray crystallography and the results obtained revealed that the indenyl ligand coordinate to titanium in an η4-tendency. Propylene polymerization was conducted with 1 in toluene or heptane as solvent at 0 °C in the presence of dried methylaluminoxane (MAO) or dried modified MAO (MMAO), which was prepared from the toluene solutions of MAO or MMAO by removing free trialkylaluminium contained. Polymerization behavior was investigated from the consumption rate of propylene in a semi-batch system. The dried MAO/toluene system showed the highest activity without any deactivation. The produced polymer in the dried MAO/toluene system had the highest molecular weight and narrowest molecular weight distribution. The number-average molecular weight of the polymer increased almost linearly with increasing polymerization time accompanied by narrowing molecular weight distribution from 1.42 to 1.37 and the number of polymer chains was almost constant. Thus, it was found that quasi-living polymerization of propylene proceeded. The 13C NMR measurement indicated that 1-dried MAO/toluene produced poly(propylene) with isotactic triad of 40%.Propylene polymerization was conducted with ansa-indenylamidodimethyltitanium complex ([t-BuNSiMe2Ind]TiMe2: 1) in toluene or heptane in the presence of dried methylaluminoxane (MAO) or dried modified MAO (MMAO), which was prepared from the toluene solutions of MAO or MMAO by removing free trialkylaluminium contained. When dried MAO was used in toluene, 1 effected quasi-living polymerization of propylene, and gave poly(propylene) with isotactic triad of 40%.

Stereospecific sequential block copolymerizations of styrene and 1,3-butadiene with a C5Me5TiMe3/B(C6F5)3/Al(oct)3 catalyst

Co-reporter:Hoang The Ban;Yasuo Tsunogae

Journal of Polymer Science Part A: Polymer Chemistry 2005 Volume 43(Issue 6) pp:1188-1195

Publication Date(Web):2 FEB 2005

DOI:10.1002/pola.20592

This article reports a new methodology for preparing highly stereoregular styrene (ST)/1,3-butadiene (BD) block copolymers, composed of syndiotactic polystyrene (syn-PS) segments chemically bonded with cis-polybutadiene (cis-PB) segments, through a stereospecific sequential block copolymerization of ST with BD in the presence of a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst. The first polymerization step, conducted in toluene at −25 °C, was attributed to the syndiospecific living polymerization of ST. The second step, conducted at −40 °C, was attributed to the cis-specific living polymerization of BD. The livingness of the whole polymerization system was confirmed through a linear increase in the weight-average molecular weights of the copolymers versus the polymer yields in both steps, whereas the molar mass distributions remained constant. The profound cross reactivity of the styrenic-end-group active species with BD toward ST led to the production of syn-PS-b-cis-PB copolymers with extremely high block efficiencies. Because of the presence of crystallizable syn-PS segments, this copolymer exhibited high melting temperatures (up to 270 °C), which were remarkably different from those of the corresponding anionic ST–BD copolymers, for which no melting temperatures were observed. Scanning electron microscopy pictures of a binary syn-PS/cis-PB blend with or without the addition of the syn-PS-b-cis-PB copolymers proved that it could be used as an effective compatibilizer for noncompatibilized syn-PS/cis-PB binary blends. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1188–1195, 2005