Researcher Database

Tamaki Nakano
Institute for Catalysis Macromolecular Science Research Division
Professor

Researcher Profile and Settings

Affiliation

  • Institute for Catalysis Macromolecular Science Research Division

Job Title

  • Professor

J-Global ID

Research Interests

  • circularly polarized light   精密重合   π-電子系ポリマー   キラルポリマー   controlled polymerization   pi-electronic polymers   chiral polymers   

Research Areas

  • Nanotechnology/Materials / Polymer chemistry

Academic & Professional Experience

  • 1999 - 2006 Nara Institute of Science and Technology Graduate School of Materials Science
  • 1999 - 2006 Associate Professor
  • 2006 - 北海道大学大学院工学研究科 教授 教授
  • 2006 - Professor
  • 1998 - 1999 Nagoya University Graduate School of Engineering
  • 1998 - 1999 Associate Professor
  • 1990 - 1998 名古屋大学工学部応用化学科 助手 (岡本佳男教授) 助手
  • 1990 - 1998 Research Associate,1990 Assistant Professor, Nagoya University1998 Associate Professor, Nagoya University1999 Associate Professor, Nara Institute of Science and Technology2006 Professor, Hokkaido University

Education

  •        - 1991  Osaka University
  •        - 1990  Osaka University
  •        - 1990  Osaka University  Graduate School, Division of Engineering Science
  •        - 1988  Osaka University
  •        - 1988  Osaka University  Graduate School, Division of Engineering Science
  •        - 1986  Osaka University
  •        - 1986  Osaka University

Association Memberships

  • バイオインダストリー協会   光化学協会   有機合成化学協会   日本化学会   高分子学会   アメリカ化学会   The American Chemical Society   The Chemical Society of Japan   The Society of Polymer Science, Japan   

Research Activities

Published Papers

  • Akihiro Kimura, Haruka Hayama, Jun-ya Hasegawa, Hassan Nageh, Yue Wang, Naofumi Naga, Mayumi Nishida, Tamaki Nakano
    POLYMER CHEMISTRY 8 (47) 7406 - 7415 1759-9954 2017/12 [Refereed][Not invited]
     
    Four polyurethanes comprising 2,2'-bipyridyl moieties incorporated in the main chain were synthesized as a novel polymer ligand for the Ir(I)-catalyzed direct borylation of aromatic compounds. The polyurethanes were insoluble in common organic solvents and soluble in dimethylsulfoxide. The borylation reaction of benzene catalyzed by Ir(I) in the presence of the polymer prepared from 4,4'-bis(hydroxylmethyl)-2,2'-bipyridyl and 1,6-diisocyanatohexane led to the catalytic activities comparable to that in the presence of 2,2'-bipyridyl, while the polymers prepared by the reactions of 4,4'-bis(hydroxylmethyl)-2,2'-bipyridyl with 1,4-diisocyanatobenzene, 1,4-diisocyanato-3-methylbenzene, and bis(4-isocyanatophenyl)methane possesed lower catalytic activities. The high activity observed using the 1,6-diisocyanatohexane-based polyurethane catalyst could have a connection to the fact that this polymer has the highest tendency to form the inter-chain hydrogen bond. The borylation reaction systems with the polymers were biphasic, where the top and bottom layers contained the product and the polymer-based catalysts, respectively. Due to the phase separation, the product isolation and catalyst recycle were readily performed through a simple decantation. The catalyst prepared from 1,6-diisocyanatohexane-based polyurethane was able to be recycled at least five times without a significant decrease in activity. Further, the regio-selectivity in borylation of toluene, anisole, and trifluoromethybenzene was studied using the polyurethane ligands as well as the corresponding small-molecular ligands.
  • Hassan Nageh, Liming Zhao, Akira Nakayama, Jun-ya Hasegawa, Yue Wang, Tamaki Nakano
    CHEMICAL COMMUNICATIONS 53 (60) 8431 - 8434 1359-7345 2017/08 [Refereed][Not invited]
     
    An effective photo-induced beta-elimination of an alcohol leading to a vinyl compound is introduced for the first time. 9-Fluorenylmethanol was irradiated in a solution using a Xe lamp and was efficiently converted to dibenzofulvene (DBF) (9-methylenefluorene) in the absence of base which is necessary in the corresponding ground-state reaction.
  • Heng Wang, Yue Wang, Xichong Ye, Haruka Hayama, Hiroyoshi Sugino, Hideyuki Nakano, Tamaki Nakano
    POLYMER CHEMISTRY 8 (4) 708 - 714 1759-9954 2017/01 [Refereed][Not invited]
     
    A novel triphenylamine containing vinyl ketone monomer, isopropenyl 4-[bis(4-methylphenyl) amino] phenyl ketone (IMAPK), was prepared from bis[(4-methylphenyl) amino] benzene and methacryloyl chloride through the Friedel-Crafts acylation. t-Butyl 4-[bis(4-methylphenyl) amino] phenyl ketone (BMAPK) was also synthesized as a monomeric unit model. IMAPK was homopolymerized and copolymerized with styrene under free-radical conditions. While homopolymerizability of IMAPK was rather low, copolymers with styrene were obtained at fair monomer conversions. The obtained polymers were proposed to possess a rather rigid, restricted conformation in which the side-chain chromophores are p-stacked on the basis of NMR spectra, and they indicated remarkable hypochromicity and red shifts in absorbance spectra and red shifts in emission spectra compared with BMAPK. In addition, the polymers exhibited red shifts in the emission spectra of which the extent was higher in a more polar solvent among cyclohexane, tetrahydrofuran, chloroform, and acetonitrile; this observation was ascribed to the conformational relaxation of the side-chain 4-[bis(4-methylphenyl) amino] phenyl group in excited states which is facilitated in a polar solvent. The conformational relaxation may be facilitated also by close interactions between the side-chain chromophore groups along the polymer chain. In addition, polymer aggregation was found to occur in solution where the size of aggregates was greater in cyclohexane than in tetrahydrofuran. Further, the polymers showed reduced oxidation potentials compared with BMAPK in cyclic voltammetry analysis, supporting that they have a pi-stacked conformation.
  • Yue Wang, Takunori Harada, Yoshihito Shiota, Kazunari Yoshizawa, Heng Wang, Sheng Wang, Xichong Ye, Masamichi Ogasawara, Tamaki Nakano
    RSC ADVANCES 7 (47) 29550 - 29553 2046-2069 2017 [Refereed][Not invited]
     
    Here we report the resolution of phosphorescent light-emitting iridium(III) bis[(4,6-difluorophenyl) pyridinato-N, C-2]-picolinate into its respective enantiomers by using chiral HPLC and the photo-induced transformation of the isolated enantiomers.
  • Zhaoming Zhang, Yue Wang, Tamaki Nakano
    MOLECULES 21 (11) 1420-3049 2016/11 [Refereed][Not invited]
     
    (R)-1,1'-Bi(2-naphthol) ((R)-BINOL) in an acetonitrile solution lost optical activity upon irradiation with an Hg-Xe lamp. HPLC resolution of the product indicated that (R)-BINOL was racemized upon irradiation, and SEC analysis suggested that a polymeric product was formed in the course of racemization. It is proposed that polymerization of BINOL can occur before it is racemized and that a unit in a polymer derived from BINOL may lose its optical activity afterwards due to in-chain racemization and/or reduction. The polymeric products seem to consist not only of BINOL residues but also of residues derived from acetonitrile as well as those derived through reduction of BINOL.
  • Yasuhito Koyama, Tamaki Nakano
    CHEMISTRY LETTERS 45 (8) 1018 - 1020 0366-7022 2016/08 [Refereed][Not invited]
     
    We describe the synthesis and properties of modified amylose containing an aryl spacer at a regular interval in its main chain as a new host polymer. The modified amylose was efficiently synthesized by copper-catalyzed alkyne-azide 1,3-dipolar cycloaddition polymerization of alkyne-containing permethylated maltohexaosyl azide 3. The polymer exhibited greater hydrophobicity than permethylated amylose. A mixture of the polymer with terthiophene formed an inclusion complex in a 10% dimethyl sulfoxide aqueous solution, leading to intermolecular chirality transfer from the polymer to terthiophene.
  • Yue Wang, Alexander L. Kanibolotsky, Peter J. Skabara, Tamaki Nakano
    CHEMICAL COMMUNICATIONS 52 (9) 1919 - 1922 1359-7345 2016 [Refereed][Not invited]
     
    Chirality induction into a uniform, star-shaped fluorene oligomer with a central truxene moiety (T3) was achieved using circularly polarized light in the presence of achiral fluorene or phenanthrene. Induction into T3 alone was difficult, suggesting that close chain packing realized through interactions of T3 with small molecules plays a role in chirality induction.
  • Weixi Yang, Tamaki Nakano
    CHEMICAL COMMUNICATIONS 51 (97) 17269 - 17272 1359-7345 2015/12 [Refereed][Not invited]
     
    5,6-Dibromo-1,10-phenanthroline and 2,9-di-n-butyl-5,6-dibromo-1,10-phenanthroline were polymerized using a Ni catalyst to afford helical polymers in which the phenanthroline moieties are densely stacked on top of each other. Polymerization of the latter monomer using a chiral catalyst led to a preferred-handed helix. This is the first Ni-catalyzed helix-sense-selective polymerization of aromatic compounds.
  • Prashant G. Gudeangadi, Takeshi Sakamoto, Yukatsu Shichibu, Katsuaki Konishi, Tamaki Nakano
    ACS MACRO LETTERS 4 (9) 901 - 906 2161-1653 2015/09 [Refereed][Not invited]
     
    (R)-1,1'-Bi(2-naphthol) was reacted with 1,4-phenylene diisocyanate leading to a mixture of linear polyurethane and cyclic compounds including a cyclic dimer and a cyclic trimer. The structure of the cyclic dimer was elucidated by X-ray crystal structure analysis. The polymer was proposed to possess a rather stiff, pi-stacked, 2/1-helical conformation on the basis of NMR, CD, and UV spectra and molecular dynamics simulations. The conformation was stable in the range of temperature of 0-60 degrees C.
  • Tamaki Nakano
    MACROMOLECULAR SYMPOSIA 355 (1) 61 - 67 1022-1360 2015/09 [Refereed][Invited]
     
    Education in Japan is segmented into 6 years of elementary school, 3 years of junior high school, 3 years of high school, and 4 years of university, with elementary and junior high education compulsory. Polymer education in Japan starts at the elementary school level, where the iodine-starch reaction is taught, typically as hands-on, experimental lessons in a science class. At the high school level, the concepts of "polymers" and "polymerization" are taught in chemistry class but not in detail. Details are treated as optional subjects in the curriculum and are not included in university entrance exams; students generally do not choose to spend much time and efforts on subjects that are not applicable to the exams. Polymer science is taught as an independent subject or an area of organic chemistry or material science at the university level.
  • Prashant G. Gudeangadi, Takeshi Sakamoto, Yukatsu Shichibu, Katsuaki Konishi, Tamaki Nakano
    ACS MACRO LETTERS 4 (9) 901 - 906 2161-1653 2015/09 [Refereed][Not invited]
     
    (R)-1,1'-Bi(2-naphthol) was reacted with 1,4-phenylene diisocyanate leading to a mixture of linear polyurethane and cyclic compounds including a cyclic dimer and a cyclic trimer. The structure of the cyclic dimer was elucidated by X-ray crystal structure analysis. The polymer was proposed to possess a rather stiff, pi-stacked, 2/1-helical conformation on the basis of NMR, CD, and UV spectra and molecular dynamics simulations. The conformation was stable in the range of temperature of 0-60 degrees C.
  • Adriana Pietropaolo, Yue Wang, Tamaki Nakano
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 54 (9) 2688 - 2692 1433-7851 2015/02 [Refereed][Not invited]
     
    A chirality-switching free-energy landscape was reconstructed on a 43-mer of poly(9,9-dioctylfluoren-2,7-diyl) (PDOF). The simulations were conducted on amorphous silica surface as well as in the vacuum phase for a single chain or for a group of sixteen chains. The achiral-to-chiral transition occurs only on amorphous silica (activation free-energy 35kcalmol(-1)), where the enantiomeric (homochiral) basins are detected. This was supported by the experiments where effective chirality induction to PDOF using circularly polarized light (CPL) was attained only for a film deposited on a quartz glass and not for a solution or a suspension. These results indicate that interactions of PDOF with amorphous silica play a crucial role in chirality switching. Importance of chain assembling was also indicated. Theoretical ECD spectra of the enantiomeric basins containing a 5(1) helix reproduce the experimental spectra.
  • Maia Merlani, Yasuhito Koyama, Hiroyasu Sato, Li Geng, Vakhtang Barbakadze, Bezhan Chankvetadze, Tamaki Nakano
    POLYMER CHEMISTRY 6 (11) 1932 - 1936 1759-9954 2015 [Refereed][Not invited]
     
    2-Methoxycarbonyl-3-(3,4-dimethoxyphenyl) oxirane was synthesized and polymerized using a cationic initiator to afford a polymer having a rather stiff, stretched conformation. The side-chain methoxycarbonyl group and 3,4-dimethoxyphenyl group of neighboring monomeric units may form a hetero pi-stacked structure between side-chain carbonyl and aromatic groups which leads to intramolecular charge transfer (ICT) interactions. 2-Ethoxy-carbonyl- 3-phenyloxirane failed in polymerization, leading only to small molecules including cyclic compounds.
  • Maia Merlani, Yasuhito Koyama, Hiroyasu Sato, Geng Li, Vakhtang Barbakadze, Bezhan Chankvetadze, Tamaki Nakano
    POLYMER CHEMISTRY 6 (12) 2356 - 2356 1759-9954 2015 [Refereed][Not invited]
  • Hiroyoshi Sugino, Yasuhito Koyama, Tamaki Nakano
    RSC ADVANCES 5 (27) 21310 - 21315 2046-2069 2015 [Refereed][Not invited]
     
    Poly(xanthon-3-ylmethacrylate) (poly(XOMA))and poly(xanthon-3-yl methacrylate-co-methyl methacrylate) (poly(XOMA-co-MMA)) having a pi-stacked conformation were synthesized as host material candidates for phosphorescence-based light emitting diodes. Poly(XOMA) harvested photo excitation energy for blue phosphorescent emission of iridium bis[(4,6-difluorophenyl) pyridinato-N, C-2] picolinate (FIrpic) in a CHCl3 solution and in film.
  • 光のキラリティーを用いた高分子らせんの構築
    中野 環
    化学工業 66 (2) 92 - 96 2015 [Refereed][Invited]
  • Maia Merlani, Yasuhito Koyama, Hiroyasu Sato, Li Geng, Vakhtang Barbakadze, Bezhan Chankvetadze, Tamaki Nakano
    POLYMER CHEMISTRY 6 (11) 1932 - 1936 1759-9954 2015 [Refereed][Not invited]
     
    2-Methoxycarbonyl-3-(3,4-dimethoxyphenyl) oxirane was synthesized and polymerized using a cationic initiator to afford a polymer having a rather stiff, stretched conformation. The side-chain methoxycarbonyl group and 3,4-dimethoxyphenyl group of neighboring monomeric units may form a hetero pi-stacked structure between side-chain carbonyl and aromatic groups which leads to intramolecular charge transfer (ICT) interactions. 2-Ethoxy-carbonyl- 3-phenyloxirane failed in polymerization, leading only to small molecules including cyclic compounds.
  • Heng Wang, Adriana Pietropaolo, Wenbin Wang, Chen-Yi Chou, Ichiro Hisaki, Norimitsu Tohnai, Mikiji Miyata, Tamaki Nakano
    RSC ADVANCES 5 (122) 101110 - 101114 2046-2069 2015 [Refereed][Not invited]
     
    The right-handed two-fold helical (2/1 helical) arrangement of benzene included in the cavity of cholic acid (CA) crystal was directly established by experimental and theoretical circular dichroism (CD) spectral studies. Experimental spectra comprised chirality elements of benzene and CA and well agreed with the theoretical spectra which considered interactions between benzene and polar groups of CA.
  • Tamaki Nakano
    CHEMICAL RECORD 14 (3) 369 - 385 1527-8999 2014/06 [Refereed][Invited]
     
    The following polymer structural transitions were achieved using light: preferred-handed helix formation for poly(9,9-di-n-octylfluoren-2,7-diyl), helix racemization (helix-helix transition) for poly(2,7-bis(4-t-butylphenyl)fluoren-9-yl acrylate) and poly(2,5-bis[4-((S)-2-methylbutyloxy)phenyl]styrene), and helix decomposition for poly(2,7-bis(4-t-butylphenyl)-9-methylfluoren-9-yl acrylate) and poly(2,7-bis(4-t-butylphenyl)fluoren-9-ylmethyl methacrylate). Although these types of transitions and chemical transformations have been studied mainly using heat or chemicals as stimuli, light can also cause these structural alterations. In the helix construction and the helix-helix transition, a key transition is a twist-coplanar conformational change of a biphenyl or an aryl-aryl unit in the side chain or the main chain of the polymer. Furthermore, the helix-helix transition was caused only by light and not by heat. The examples discussed in this review are expected to trigger off a new direction in synthesis and reaction of chiral polymers.
  • Yue Wang, Takeshi Sakamoto, Yasuhito Koyama, Yuma Takanashi, Jiro Kumaki, Jiaxi Cui, Xinhua Wan, Tamaki Nakano
    POLYMER CHEMISTRY 5 (3) 718 - 721 1759-9954 2014/02 [Refereed][Not invited]
     
    Poly(2,5-bis[4-((S)-2-methylbutyloxy)phenyl]styrene) having a helical conformation underwent helix-helix transition upon photo-irradiation. Conformational transition can significantly alter polymer properties, and so far thermal stereomutation has been studied. However, as for photo-induced mutation, only helix-helix transition (irreversible CD-active to CD-silent helix transition) of a polyacrylate has been explored. Here, we present mutation of the polystyrene derivative. Chiroptical, viscometric, and vibrational spectroscopic analyses indicated the polymer mutated from an optically active helix to another optically inactive helix with a different shape.
  • Kento Watanabe, Yasuhito Koyama, Nozomu Suzuki, Michiya Fujiki, Tamaki Nakano
    POLYMER CHEMISTRY 5 (3) 712 - 717 1759-9954 2014/02 [Refereed][Not invited]
     
    An alternating copolymer consisting of achiral and chiral units emits remarkably efficient CPL on photo-excitation. The main-chain twist bias is enhanced by thermal annealing by the factor of 10(4) in the ground state. An anisotropy factor of the polymer in the excited state is greater by approximately an order of magnitude compared with that in the ground sate.
  • Toshikage Asakura, Hitoshi Yamato, Keita Tanaka, Ryuichi Takahashi, Hisatoshi Kura
    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY 27 (2) 227 - 230 0914-9244 2014 [Refereed][Not invited]
  • Pietropaolo, Adriana, Nakano, Tamaki
    American Chemical Society 135 (15) 5509 - 5512 0002-7863 2013/04 [Refereed][Not invited]
  • Yue Wang, Takeshi Sakamoto, Tamaki Nakano
    CHEMICAL COMMUNICATIONS 48 (13) 1871 - 1873 1359-7345 2012 [Refereed][Not invited]
     
    A preferred-handed helical conformation was induced to poly(9,9-dioctylfluoren-2,7-diyl) (PDOF) in a thin film form upon irradiation with single-handed circularly polarized light (CPL) where the induction was reversible.
  • Organic semiconductor compounds with high charge mobility and organic thin films comprising them
    Nakano, Tamaki, Sakamoto, Takeshi, Tanaka, Kenta, Higashimura, Hideyuki
    2012 [Refereed][Not invited]
  • Organic semiconductor compound
    Nakano, Tamaki, Sakamoto, Takeshi, Tanaka, Kenta, Higashimura, Hideyuki
    2012 [Refereed][Not invited]
  • Compound and film containing same for electroluminescent display devices
    Higashimura, Hideyuki, Kobayashi, Norifumi, Nakano, Tamaki, Sakamoto, Takeshi, Yu, Jin-Meng
    2012 [Refereed][Not invited]
  • Method for modifying polymer compound and method for producing films containing modified polymer compounds
    Higashimura, Hideyuki, Kobayashi, Norifumi, Nakano, Tamaki, Sakamoto, Takeshi
    2012 [Refereed][Not invited]
  • Light creates polymer helicity
    Nakano, Tamaki
    Kobunshi 61 (10) 767 - 768 2012 [Refereed][Not invited]
  • A study on conformational regulation of polymer chains by photostimulation
    Nakano, Tamaki
    Asahi Garasu Zaidan Josei Kenkyu Seika Hokoku (a) 1 - 6 2012 [Not refereed][Not invited]
  • Takeshi Sakamoto, Kento Watanabe, Yukatsu Shichibu, Katsuaki Konishi, Shin-Ichiro Sato, Tamaki Nakano
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 49 (4) 945 - 956 0887-624X 2011/02 [Refereed][Not invited]
     
    2,7-Bis(4-t-butylphenyl)-9-methylfluoren-9-yl acrylate (BBPMFA) was synthesized and polymerized using alpha,alpha'-azobisisobutyronitrile or n-Bu(3)B-air as a radical initiator and using the complex of 9-fluorenyllithium with (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine as an optically active anionic initiator. Although the radical polymerization led to rather low-molecular-weight products at low yields, the anionic polymerization afforded polymers with higher molecular weights in higher yields. The poly(BBPMFA) obtained by the anionic polymerization was slightly rich in isotacticity (meso diad 57%) and showed an intense circular dichroism (CD) spectrum and large dextrorotation. The intensity of the CD spectrum and magnitude of optical activity increased with an increase in M(n), suggesting that the polymer possesses a preferred-handed helical conformation. The CD spectrum disappeared within 1 s on irradiation to the polymer in a CHCl(3) solution using a 500-W Hg-Xe lamp. This was ascribed to fast photolysis of the ester linkage leading to a loss of helical conformation of the entire chain. Photolysis products of poly(BBPMFA) were poly(acrylic acid) and 2,7-bis(4-t-butylphenyl)-9-methylenefluorene (2,7-bis(4-t-butylphenyl)dibenzofulvene). The photolysis reaction seemed to proceed through the "unzipping" mechanism. The rate constant of photolysis of poly(BBPMFA) under irradiation at monochromated 325 nm was around 0.01 s(-1) independent of molecular weight. Photolysis at 325 nm was approximately 2400 times faster than that for chemical ester solvolysis under a neutral condition in the dark. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 945-956, 2011
  • Kento Watanabe, Takeshi Sakamoto, Tamaki Nakano
    CHIRALITY 23 (1E) E28 - E34 0899-0042 2011 [Refereed][Not invited]
     
    2,7-Bis(4-t-butylphenyl) fluoren-9-ylmethyl methacrylate (BBPFMMA) was synthesized as a new candidate of a bulky monomer suitable for asymmetric anionic polymerization (IUPAC nomenclature: asymmetric helix-chirogenic polymerization) leading to a preferred-handed helical, optically active polymer. The new monomer was polymerized using the complex of 9-fluorenyllithium and (S)-(1)-1-(2-pyrrolidinylmethyl) pyrrolidine in toluene at -78 degrees C. As opposed to the original intention to obtain a polymethacrylate, the monomer seemed to undergo structural transition (decomposition) giving 2,7-bis(4-t-butylphenyl) dibenzofulvene and the obtained polymer was most probably a terpolymer of BBPFMMA, 2,7-bis(4-t-butylphenyl) dibenzofulvene, and methacrylic acid. The obtained polymer showed circular dichroism (CD) spectra, indicating that chirality had been introduced to the copolymer chain during the course of polymerization. On photo irradiation, the polymer underwent a structural transition involving a remarkable decrease in apparent molecular weight measured by size-exclusion chromatography (SEC) and changes in FT-IR spectral patterns. However, the CD spectrum of the polymer was not obviously altered by irradiation, indicating that polymer chirality is not affected by light. Chirality 23: E28-E34, 2011. (C) 2011 Wiley Periodicals, Inc.
  • Chiral hyperbranched polymer emitting efficient circularly polarized light (CPL)
    Nakano, Tamaki, Watanabe, Kento, Sakamoto, Takeshi
    Fain Kemikaru 40 (9) 40 - 46 2011 [Refereed][Not invited]
  • Kento Watanabe, Takeshi Sakamoto, Makoto Taguchi, Michiya Fujiki, Tamaki Nakano
    CHEMICAL COMMUNICATIONS 47 (39) 10996 - 10998 1359-7345 2011 [Refereed][Not invited]
     
    An optically active, pi-stacked poly[2,7-bis(4-tert-butylphenyl)dibenzofulvene] having a preferred-handed helical conformation was synthesized by anionic polymerization. A thin film sample of the polymer exhibited broad-band white circularly polarized light (CPL) emission on photo excitation.
  • Juin-Meng Yu, Takeshi Sakamoto, Kento Watanabe, Seiichi Furumi, Nobuyuki Tamaoki, Yun Chen, Tamaki Nakano
    CHEMICAL COMMUNICATIONS 47 (13) 3799 - 3801 1359-7345 2011 [Refereed][Not invited]
     
    An optically active, hyperbranched poly(fluorenevinylene) derivative was synthesized by polymerization of (-)-2,4,7-tris(bromomethyl)-9-neomenthyl-9-pentylfluorene. A spin-coated film sample of the polymer exhibited efficient circularly polarized light (CPL) emission in the visible range of 400-700 nm on photo excitation even without annealing processes leading to chain ordering.
  • Takeshi Sakamoto, Toshio Nishikawa, Yasuyuki Fukuda, Shin-ichiro Sato, Tamaki Nakano
    MACROMOLECULES 43 (14) 5956 - 5963 0024-9297 2010/07 [Refereed][Not invited]
     
    1-(p-Vinylphenyl)dibenzosuberyl methacrylate (VDBSMA) having two reactive vinyl groups in a molecule was synthesized and polymerized using alpha,alpha'-azobis(isobutyronitrile) as a radical initiator and using the complexes of 9-fluorenyllithium with (S)-(+)-1-(2-pyriolidinylmethyl)pyrrolidine, (-)-sparteine, and (S,5)-(+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane as optically active anionic initiators The lice radical polymerization led to an insoluble material, indicating that both methacrylic and styrenic moieties participated in the polymerization and a doss-linked gel was produced In contrast, the anionic polymerization proceeded exclusively through the addition reaction of methacrylic moiety leaving the styrenic vinyl group intact leading to soluble polymers The resulting poly(VDBSMA)s having a polymethacrylate-type main-chain structure were highly isotactic and showed high optical activity and intense circular dichroism (CD) spectra, indicating that the polymers have a single-handed helical conformation Thus, a single-handed helical polymer having side-chain vinyl groups, which can be chemically modified, was successfully synthesized The side-chain vinyl group was converted to 2-hydroxyethyl group, 1,2-dihydroxyethyl group, and carboxylic acid group by polymer reaction without seriously deterriorating the single-handed helical conformation of the polymer. In this way, single-handed helical polymers with side-chain protonic groups which would be difficult to be prepared by direct asymmetric anionic polymerization of the corresponding monomers were conveniently synthesized In addition, radical polymerization of poly(VDBSMA) as a macromonomer afforded an optically active adduct consisting of single-handed helical chains
  • Tamaki Nakano
    POLYMER JOURNAL 42 (2) 103 - 123 0032-3896 2010/02 [Refereed][Not invited]
     
    Macromolecular conformation often has a significant effect on the properties of polymeric materials, and hence, conformational control in synthesizing a polymer is an important goal in polymer science. As a new conformational motif of vinyl polymers having side-chain pi-electronic groups, we have introduced a 'pi-stacked structure' in which side-chain chromophores are regularly stacked on top of each other and main-chain C-C bonds have a nearly all-trans, zigzag conformation. pi-Stacked polymers can be prepared by vinyl polymerization of dibenzofulvene (DBF) and its derivatives. On the basis of the controlled structure, poly(DBF) and its derivatives exhibit unique photophysical and electronic properties as vinyl polymers. In addition, introduction of chirality to pi-stacked polymers was also achieved. In this review, the synthesis of poly(DBF) and its derivatives and their structural analyses and properties are described. Polymer Journal (2010) 42, 103-123; doi:10.1038/pj.2009.332
  • Synthesis and photo-induced stereomutation of a single-handed, optically active helical polyacrylate
    Nakano, Tamaki, Sakamoto, Takeshi, Sato, Shin-ichiro
    Abstracts of Papers, 239th ACS National Meeting, San Francisco, CA, United States, March 21-25 2010 [Refereed][Not invited]
  • Synthesis, polymer chain conformational structure, and photoelectronic properties of π-stacked polymers
    Nakano, Tamaki
    Kobunshi 59 (3) 164 - 168 2010 [Refereed][Not invited]
  • Optical device used as optical switche and optical modulator
    Nakano, Tamaki, Sakamoto, Takeshi, Higashimura, Hideyuki
    2010 [Refereed][Not invited]
  • Synthesis and photo-induced stereomutation of a single-handed helical, optically active polyacrylate
    Nakano, Tamaki, Sakamoto, Takeshi, Sato, Shin-ichiro
    Polymer Preprints 51 (1) 145 - 146 2010 [Refereed][Not invited]
  • Synthesis and opto-electronic function of π-stack polymers
    nakano tamaki
    Mirai Zairyo 10 (10) 25 - 31 2010 [Refereed][Not invited]
  • A Reactive Helix: Synthesis, Chemical Modification, and Polymerization
    Macromolecules 5956  2010 [Not refereed][Not invited]
  • Tamaki Nakano, Mitsuru Tanikawa, Osamu Nakagawa, Tohru Yade, Takeshi Sakamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 47 (1) 239 - 246 0887-624X 2009/01 [Refereed][Not invited]
     
    Dibenzofulvene (DBF) affords a polymer having pi-stacked conformation by anionic, cationic, and free-radical polymerization. In this study, DBF was polymerized anionically using potassium menthoxide as initiator to obtain optically active poly(DBF) having a chiral menthoxy group as a terminal group. The obtained polymer indicated circular dichroism (CD) absorption bands in the absorption wavelength range of fluorenyl group, indicating that chiral conformation was induced to the stacked main chain by the influence of the terminal group. The CD intensity was reversibly affected by temperature of measurement; hence, the chiral conformation may be rather dynamic. The effect of the terminal group was found to decrease as the chain length increased. Theoretical CD calculation indicated that the obtained polymer has a left-banded helical conformation and that the dihedral angle between neighboring monomeric units might be about 10-20 degrees. (c) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 239-246, 2009
  • Takeshi Sakamoto, Yasuyuki Fukuda, Shin-ichiro Sato, Tamaki Nakano
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 48 (49) 9308 - 9311 1433-7851 2009 [Refereed][Not invited]
  • Tamaki Nakano, Tohru Yade
    CHEMISTRY LETTERS 37 (3) 258 - 259 0366-7022 2008/03 [Refereed][Not invited]
     
    Cation radicals of oligomers and polymers of dibenzofulvene having a pi-stacked conformation showed broad absorption bands based on charge resonance in near IR region, which red-shifted with increasing degree of polymerization, indicating that charge delocalization takes place through multiple, stacked fluorene moieties.
  • Chiral macromolecules and their stationary phases for chromatography and chromatography packings for optical isomer separation
    Nakano, Tamaki, Yaegashi, Takayuki, Tsuji, Masashi
    2008 [Refereed][Not invited]
  • Optically active luminescent polymers and their manufacture
    Nakano, Tamaki, Higashimura, Hideyuki
    2008 [Refereed][Not invited]
  • Dibenzofulvene-type monomers and polymers, their compositions with high electric conductivity, and charge transporters using them
    Nakano, Tamaki, Kotani, Akihiro, Gao, Mingtien
    2008 [Refereed][Not invited]
  • Tamaki Nakano, Tohru Yade, Yasuyuki Fukuda, Kazuyuki Takewaki
    CHEMISTRY LETTERS 36 (2) 320 - 321 0366-7022 2007/02 [Refereed][Not invited]
     
    Block copolymers of dibenzofulvene and methyl methacrylate obtained by living anionic polymerization formed stable, soluble nanoparticles by in situ molecular aggregation of the poly(dibenzofulvene) segments having a rigid pi-stacked conformation; the nanoparticles indicated red-shifted absorption bands and reduced oxidation potential relative to a single chain poly (dibenzofulvene).
  • Composition with asymmetric structure and simple process for producing the same
    Nakano, Tamaki, Yaegashi, Takayuki, Tuji, Masashi
    2007 [Refereed][Not invited]
  • Synthesis, structure, and function of π-stacked polymers
    Nakano, Tamaki
    Jasco Report 49 (1) 1 - 6 2007 [Refereed][Not invited]
  • Charge-transporting materials containing fluorene polymers
    Nakano, Tamaki, Kotani, Akihiro, Gao, Ming-Tien
    2007 [Refereed][Not invited]
  • Coropceanu, V, T Nakano, NE Gruhn, O Kwon, T Yade, K Katsukawa, JL Bredas
    JOURNAL OF PHYSICAL CHEMISTRY B 110 (19) 9482 - 9487 1520-6106 2006/05 [Refereed][Not invited]
     
    The molecular parameters governing charge transport along a pi-stacked fluorene chain in poly( dibenzofulvene) are studied by a joint experimental and theoretical approach involving high-resolution gas-phase photoelectron spectroscopy and quantum-mechanical methods. We specifically investigate the electronic couplings between fluorene moieties as well as the intramolecular reorganization energies, for both holes and electrons. Our results indicate that a pi-stacked fluorene chain favors hole transport over electron transport. The values for electronic couplings and reorganization energies estimated here are compared with those derived recently for pentacene.
  • T Yade, T Nakano
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 (1) 561 - 572 0887-624X 2006/01 [Refereed][Not invited]
     
    2,7-Di-t-butyldibenzofulvene (tBu(2)DBF), a bulky dibenzofulvene derivative, was polymerized using n-butyllithium as initiator in tetrahydrofuran at -78 degrees C and in toluene at 0 degrees C. tBu(2)DBF afforded mainly oligomers up to trimer even at [monomer](0)/[initiator](0) = 20 ([monomer](0) = 0.2 M) at -78 degrees C and 0 degrees C, indicating that this monomer is much less reactive than dibenzofulvene (DBF), its parent compound. The reaction at the same [monomer](0)/[initiator](0) ratio at an elevated [monomerlo gave a small amount of insoluble polymer. The oligomers indicated a hypochromic effect in the absorption spectra and only monomer emission in the fluorescent spectra. The conformation of the trimer and the dimer was examined by means of NOESY NMR spectra and semiempirical calculations. In the trimer conformation, the fluorene moieties of the central and the initiation-side monomeric units were found to be closely stacked on top of each other, while the termination-side monomeric unit appeared to be in a faster conformational dynamics compared with the other monomeric units. Although the dimer seemed to have a relatively flexible conformation, a pi-stacked structure appeared to be involved in the conformational dynamics to show hypochromicity. The results of this study suggest that the reported intramolecular excited dimer (excimer) formation of the poly- and oligo(DBF)s [J Am Chem Soc 2003, 125, 15474] is based on a slight, local conformational change upon photo absorption, leading to a closer pi-stacked alignment of two neighboring fluorene units than that in the ground state. Such a local conformational transition may be difficult for the tBu(2)DBF trimer because of steric repulsion of the t-butyl groups. (c) 2005 Wiley Periodicals, Inc.
  • Tamaki Nakano, Takayuki Yaegashi, Osamu Nakagawa, Masashi Tsuji, Mitsuru Tanikawa
    KOBUNSHI RONBUNSHU 63 (7) 492 - 497 0386-2186 2006 [Refereed][Not invited]
     
    2,7-Dipentyldibenzofulvene (PDBF) was synthesized and anionically polymerized using complexes of 9-fluorenyllithium and optically active ligands. The obtained poly (PDBF) s having no asymmetric centers showed intense circular dichroism in film due purely to the chiral conformation of the main chain.
  • Optically active copolymer as chromatography packings for optical-isomer separation and its preparation
    Nakano, Tamaki, Yaegashi, Takayuki, Tuji, Masashi
    2006 [Refereed][Not invited]
  • T Nakano, T Yade, Y Fukuda, T Yamaguchi, S Okumura
    MACROMOLECULES 38 (20) 8140 - 8148 0024-9297 2005/10 [Refereed][Not invited]
     
    Free-radical polymerization of dibenzofulvene (DBF) was carried out under various conditions. The radical polymerization proceeded exclusively in vinyl fashion without isomerization of the growing radical or aromatic substitution by the initiator fragment. The polymerization was highly conformation-specific (stereospecific), giving a polymer with a pi-stacked conformation in which the main-chain C-C bonds are nearly all trans and the side-chain fluorene moieties are stacked on top of each other. The conformation specificity (stereospecificity) of the DBF radical polymerization was almost similar to that in the anionic polymerization although the radical polymerization products appeared to have a small amount of irregular, defective conformation incorporated into the mostly pi-stacked chain. The conformation specificity was affected by the initial monomer concentration and reaction temperature. This observation was explained by a proposed mechanism where two types of the growing radicals having different conformations mediate the polymerization. The poly(DBF) obtained by the radical polymerization showed lower fluorescent intensity and higher solubility possibly due to a small amount of conformational defects.
  • T Nakano, O Nakagawa, M Tanaka, T Yade, M Tsuji
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 43 (5) 1150 - 1154 0887-624X 2005/03 [Refereed][Not invited]
  • Synthesis and function of a π-stacked polymer
    Nakano, Tamaki
    Kagaku Kogyo 56 (3) 195 - 202 2005 [Refereed][Not invited]
  • Radical polymerization using molecular templates
    Nakano, Tamaki
    Kagaku 60 (8) 66 - 67 2005 [Refereed][Not invited]
  • H Ishizawa, T Nakano, T Yade, M Tsuji, O Nakagawa, T Yamaguchi
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 42 (18) 4656 - 4665 0887-624X 2004/09 [Refereed][Not invited]
     
    Poly(9-fluoreneyl methacrylate) was obtained through anionic polymerization with t-BuLi and t-BuMgBr and through radical polymerization with alpha,alpha'-azobisisobutyronitrile. Anionic polymerization with t-BuLi in tetrahydrofuran and radical polymerization afforded syndiotactic polymers (rr similar to 90%), whereas anionic polymerization with Li and Mg initiators in toluene and CH,Cl, led to isotactic polymers. The thermal and photophysical properties of the polymers were examined. A syndiotactic polymer tended to show higher glass transition and decomposition temperatures than an isotactic polymer. However, polymers with different tacticities were not likely to assume specific, distinctive conformations such as a helix or a pi-stacked conformation in solution. An isotactic polymer showed stronger interactions in a CH,Cl, solution with 2,4,7-trinitro-9-fluorenylidenemalononitrile, an electron-acceptor molecule, than a syndiotactic polymer. (C) 2004 Wiley Periodicals, Inc.
  • S Habaue, T Satonaka, T Nakano, Y Okamoto
    POLYMER 45 (15) 5095 - 5100 0032-3861 2004/07 [Refereed][Not invited]
     
    The molecular imprinting method was applied for synthesizing gels with a chiral helical cavity using various bifunctional vinyl monomers, such as alpha-(benzyloxymethyl)acrylic acid derivatives as a monomer, and one-handed helical (+)-poly(diphenyl-2-pyridylmethyl methacrylate) as a template. The chiral gels were almost quantitatively prepared after removal of the template polymer by hydrolysis of the ester groups. The obtained gels exhibited chiral resolution powers toward various racemates, such as trans-stilbene oxide and Troger's base, and the substituents on the phenyl group of the monomer significantly affected the recognition ability. The observed separation factors were higher than those of the gels prepared from the mono-functional vinyl monomer, methacrylic acid. (C) 2004 Published by Elsevier Ltd.
  • Y Gotoh, Y Nagara, T Nakano, Y Okamoto, Y Ohkoshi, M Nagura
    JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS 42 (5) 800 - 808 0887-6266 2004/03 [Refereed][Not invited]
     
    The viscoelastic behavior and molecular motion of highly syndiotactic poly(vinyl alcohol) (S-PVA) fibers with a dyad syndiotacticity (r) of 69% were studied by dynamic mechanical thermal analysis and wide-angle X-ray diffraction and compared with those of atactic poly(vinyl alcohol) (A-PVA) fibers with r = 54%. The beta(c) dispersion, based on the molecular motion of the chain molecules in the crystalline regions, was observed for A-PVA around 120-140 degreesC, and the only primary (alpha(c)) dispersion was observed for S-PVA around 180 degreesC. The thermal expansion coefficients for the a and c axes of the A-PVA crystal changed discontinuously around 120 degreesC, which corresponded to the beta(c) dispersion. For S-PVA, the coefficient for the (002) plane changed discontinuously around 100 degreesC, similarly to A-PVA, but that for the (100) plane remained unchanged between 20 and 220 degreesC. These results showed that the intermolecular hydrogen bonding of S-PVA was stronger in the direction of the a axis than in the other directions, suppressing the beta(c) dispersion. The storage modulus and thermal expansion coefficient of the (020) plane (molecular axis) of S-PVA decreased markedly around 180 degreesC, and this indicated that the alpha(c) dispersion was due to the torsional motion of the molecular chains in the crystalline regions. (C) 2004 Wiley Periodicals, Inc.
  • T Nakano, T Yade, M Yokoyama, N Nagayama
    CHEMISTRY LETTERS 33 (3) 296 - 297 0366-7022 2004/03 [Refereed][Not invited]
     
    Hole drift mobility of poly(dibenzofulvene) was found to be 2.7 x 10(-4) cm(2)V(-1) s(-1) at 299 K at a field strength of 7 x 10(5) Vcm(-1) by the time-of-flight (TOF) measurement on a cast film containing 2,4,7-trinitrofluorenylidene-9-malononitrile as an electron acceptor. This value is higher than that of main-chain pi-conjugating poly(pi-phenylenevinylene) (I X 10(-5) cm(2)V(-1)s(-1)), is comparable to that of main-chain sigma-conjugating poly(methylphenylsilane) (I x 10(-4) cm(2)V(-1)s(-1)), and is slightly lower than that of Se (10(-4) cm(2)V(-1)s(-1) order), an inorganic semiconductor.
  • Crystalline block copolymers and adhesives using them for semiconductor wafer dicing
    Nakano, Tamaki, Ando, Takashi
    2004 [Refereed][Not invited]
  • T Nakano, O Nakagawa, M Tsuji, M Tanikawa, T Yade, Y Okamoto
    CHEMICAL COMMUNICATIONS (2) 144 - 145 1359-7345 2004/01 [Refereed][Not invited]
     
    Poly(2,7-di-n-pentyldibenzofulvene)s with no stereocenters, obtained by anionic polymerization using chiral 9-fluorenyllithium ligand complexes, showed intense circular dichroism in film form due purely to the chiral conformation of the main chain, while no chiroptical properties were detectable in solution.
  • Method for production of molecule-recognition polymers useful as stationary phase for chromatography
    Okamoto, Yoshio, Habagami, Shigeki, Nakano, Tamaki
    2004 [Refereed][Not invited]
  • π-Stacked poly(dibenzofulvene): Structure and photophysical/electronic properties
    Nakano, Tamaki, Yade, Tohru
    Abstracts of Papers, 227th ACS National Meeting, Anaheim, CA, United States 2004 [Refereed][Not invited]
  • π-Stacked poly(dibenzofulvene): structure and photophysical/electronic properties
    Nakano, Tamaki, Yade, Tohru
    Nakano, Tamaki; Yade, Tohru 45 (1) 191  2004 [Refereed][Not invited]
  • T Nakano, T Yade
    KOBUNSHI RONBUNSHU 61 (4) 282 - 288 0386-2186 2004 [Refereed][Not invited]
     
    Asymmetric radical polymerization of N-cyclohexylmaleimide was attempted using alpha,alpha'-azobisisobutyronitrile (AIBN) as an initiator and (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminatocobalt(II) (1) as an optically active additive in a tetrahydrofuran-pyridine mixture and in pure tetrahydrofuran: the reaction was only inhibited by the cobalt complex. However, it was found that introduction of a small amount Of O-2 or air to the inhibited reaction system in tetrahydrofuran-pyridine effectively promoted polymerization, and AIBN was not necessary to achieve the polymerization. O-2 or air did not promote polymerization in pure tetrahydrofuran. A reaction mechanism involving an anionic propagating species was proposed; interaction Of 1-O-2 complex with the monomer caused electron transfer from the former to the latter, generating an anionic species in which coordination of pyridine to Co seems to be indispensable. The polymers obtained in the 1-O-2-monomer systems were optically active, based on a chiral main-chain configuration.
  • Production method of living polymerization catalysts
    Nakano, Tamaki
    2004 [Refereed][Not invited]
  • Development of new anion polymerization initiator, aiming ease use for precise polymerization method
    Nakano, Tamaki, Yaudem, Tohru, Nakagawa, Osamu, Tsuhi, Masashi
    Setchaku 48 (8) 352 - 359 2004 [Refereed][Not invited]
  • T Nakano, T Yade
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 (50) 15474 - 15484 0002-7863 2003/12 [Refereed][Not invited]
     
    Dibenzofulvene (DBF) was polymerized using anionic initiators to afford a vinyl polymer. Oligo(DBF)s having from two to eight side-chain fluorene moieties bearing different chain-terminal groups were isolated by preparative size-exclusion chromatography. The structures of the isolated oligomers were revealed by single-crystal X-ray and H-1 NMR analyses. Both in solution and in crystal, the in-chain fluorene moieties stacked on top of each other, while the terminal conformation varied depending on the terminal group. These conformational characteristics were supported by molecular mechanics and dynamics calculations. The oligomers and polymers indicated hypochromism and red shift in UV absorption spectra and exclusive excimer emission in fluorescence spectra. In addition, reduced oxidation potentials were observed for the oligomers in electrochemical analyses, which suggests charge delocalization over the a-stacked electron systems. The photophysical and electrochemical effects increased with the chain length of the oligomers and leveled off around the chain length of an oligomer consisting of five fluorene units.
  • T Nakano, T Yade, Y Okamoto
    MACROMOLECULES 36 (10) 3498 - 3504 0024-9297 2003/05 [Refereed][Not invited]
     
    This report revises the interpretations of the reaction mechanism in the polymerization of N-cyclohexylmaleimide (CHMI) in the presence of alpha, alpha'-azobis(isobutyronitrile) (AIBN) and (R, R)-N, N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminatocobalt(II) (1) [Macromolecules 2000,33, 1489]. Although we proposed that the reaction was mediated by a radical species and that the interaction between growing polymer radical with 1 induced chirality in the main chain in the earlier report, the results in the present article indicate that the systems reported in the earlier report were most probably contaminated by a small amount of air and that the polymerization proceeds via an anionic species that was produced by the interaction of the monomer, 1, and O-2. The effect of the contamination was overlooked due to the lack of a control experiment using O-2 in the absence of AIBN in our earlier study. In this work, the polymerization of CHMI was performed in the presence and absence of 1, O-2, alpha, alpha'-azobis-(isobutyronitrile) (AIBN), and protonic additives (methanol and acetic acid). The results indicated the following: (1) the polymerization in a tetrahydrofuran-pyridine mixture occurs in the presence of 1 and a small amount of oxygen even without using AIBN; (2) the reaction does not take place in the presence of 1 alone or in the presence of 1 and AIBN under a strictly controlled N-2 atmosphere; (3) a small amount of AcOH completely inhibits the polymerization with 1 and O-2 while 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) does not kill the reaction; and (4) the polymer was likely to possess -OH or -OOH groups at the chain terminals (a telechelic structure). On the basis of these observations, we withdraw our earlier, wrong interpretation that the polymerization is mediated by a radical species and conclude that the polymerization and the observed stereochemistry are effected by an anionic mechanism.
  • T Nakano, O Nakagawa, T Yade, Y Okamoto
    MACROMOLECULES 36 (5) 1433 - 1435 0024-9297 2003/03 [Refereed][Not invited]
  • Synthesis and thermal decomposition of a dibenzofulvene-O2 copolymer
    Nakano, Tamaki, Nakagawa, Osamu, Yade, Tohru
    Abstracts of Papers, 226th ACS National Meeting, New York, NY, United States 2003 [Refereed][Not invited]
  • Synthesis and thermal decomposition of a dibenzofulvene-O2 copolymer
    Nakano, Tamaki, Nakagawa, Osamu, Yade, Tohru
    PMSE Preprints (89) 365  2003 [Refereed][Not invited]
  • Acrylic polymer and charge transport material
    Ishizawa, Hideaki, Nakano, Tamaki
    2003 [Refereed][Not invited]
  • Novel polyester having π-conjugated group in side chain and charge transporting material using the same
    Nakano, Tamaki
    2003 [Refereed][Not invited]
  • Heat-decomposable polymers
    Nakano, Tamaki
    2003 [Refereed][Not invited]
  • Optically active high-molecular compounds
    Nakano, Tamaki
    2003 [Refereed][Not invited]
  • Y Okamoto, S Habaue, Y Isobe, T Nakano
    MACROMOLECULAR SYMPOSIA 183 83 - 88 1022-1360 2002/07 [Refereed][Not invited]
     
    A clear effect of Lewis acids, such as scandium trifluoromethanesulfonate [Sc(OTf)(3)], on stereocontrol during the radical polymerization of a designed monomer, benzyl (x(methoxy methyl)acrylate was found. This Lewis acid also influenced the stereochemistry in the radical polymerzation of methyl methacrylate giving a less syndiotactic and more isotactic polymer, although many Lewis acids were not effective. A catalytic amount of Lewis acids, such as Y(OTf)(3) and Yb(OTf)(3). also significantly enhanced isotactic-specificity during the radical polymerization of acrylamide and its derivatives. N-isopropylacrylamide (NIPAM) and N,N-dimethylacrylamide. Obvious solvent and temperature effects on tacticity were observed in these polymerizations, and poly(NIPAM) with >80% triad isotactic content has been obtained in the presence of Lewis acids.
  • T Nakano, K Tsunematsu, Y Okamoto
    CHEMISTRY LETTERS (1) 42 - 43 0366-7022 2002/01 [Refereed][Not invited]
     
    The radical polymerization of 1-phenyldibenzosuberyl methacrylate in the presence of an optically active cobalt(II) complex led to an optically active polymer having a single-handed helical conformation.
  • Synthesis of single-handed helical polymethacrylates from designed bulky monomers by anionic and free radical catalyses
    Okamoto, Yoshio, Tsunematsu, Kumiko, Ueda, Kiyoko, Hidaka, Yasuaki, Kinjo, Naotaka, Nakano, Tamaki
    ACS Symposium Series (812) 11 - 23 2002 [Refereed][Not invited]
  • Poly(vinyl alcohol) fibers and production methods therefor
    Okamoto, Yoshio, Nakano, Tamaki, Habagami, Shigeki, Sawamoto, Mitsuo, Kamigaito, Masami, Nagata, Naohiko, Nagae, Yoshitaka, Terada, Kazutoshi, Ootake, Tomiaki
    2002 [Refereed][Not invited]
  • Regulation of stereoregularity in radical polymerization of unsaturated carboxylic acids with metal Lewis acid catalysts
    Okamoto, Yoshio, Nakano, Tamaki, Habagami, Shigeki, Sawamoto, Mitsuo, Kamigaito, Masaki, Nagata, Naohiko, Nagae, Yoshitaka, Terada, Kazutoshi, Otake, Tomiaki, Okano, Yoshimichi
    2002 [Refereed][Not invited]
  • Synthesis of polydibenzofulvene having stacked π-electron systems, a new potential polymer for photonics and electronics
    Nakano, Tamaki, Yade, Tohru, Ishizawa, Hideaki, Nakagawa, Osamu, Okamoto, Yoshio
    Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) 43 (2) 609  2002 [Refereed][Not invited]
  • Synthesis of polydibenzofulvene having stacked π-electron systems: A new potential polymer for photonics and electronics
    Nakano, Tamaki, Yade, Tohru, Ishizawa, Hideaki, Nakagawa, Osamu, Okamoto, Yoshio
    Abstracts of Papers, 224th ACS National Meeting, Boston, MA, United States 2002 [Refereed][Not invited]
  • π-stacked polymer having unique optical property and solubility and polymerizable monomer therefor
    Nakano, Tamaki
    2002 [Refereed][Not invited]
  • T Nakano, Y Okamoto
    CHEMICAL REVIEWS 101 (12) 4013 - 4038 0009-2665 2001/12 [Refereed][Not invited]
  • T Nakano, K Takewaki, T Yade, Y Okamoto
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 123 (37) 9182 - 9183 0002-7863 2001/09 [Refereed][Not invited]
  • Y Isobe, T Nakano, Y Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 39 (9) 1463 - 1471 0887-624X 2001/05 [Refereed][Not invited]
     
    The free-radical polymerizations of methyl methacrylate (MMA), ethyl methacrylate, isopropyl methacrylate, and 2-methoxyethyl methacrylate were carried out in the presence of various Lewis acids. The MMA polymerization in the presence of scandium trifluoromethanesulfonate [Sc(OTf)(3)] in toluene or CHCl3 produced a polymer with a higher isotacticity and heterotacticity than that produced in the absence of Sc(OTf)(3). Similar effects were observed during the polymerization of the other monomers. ScCl3, Yb(OTf)(3), Er(OTf)(3), HfCl4, HfBr4, and In(OTf)(3) also increased the isotacticity and heterotacticity of the polymers. The effects of the Lewis acids were greater in a solvent with a lower polarity and were negligible in tetrahydrofuran and N,N-dimethylformamide. Sc(OTf)(3) was also found to accelerate the polymerization of MMA. On the basis of an NMR analysis of a mixture of Sc(OTf)(3), MMA, and poly(methyl methacrylate), the monomer-Sc(OTf)(3) interaction seems to be involved in the stereochemical mechanism of the polymerization. (C) 2001 John Wiley & Sons, Inc.
  • T Nakano, Y Satoh, Y Okamoto
    MACROMOLECULES 34 (8) 2405 - 2407 0024-9297 2001/04 [Refereed][Not invited]
  • NAKANO Tamaki, KINJO Naotaka, HIDAKA Yasuaki, OKAMOTO Yoshio
    Polymer Journal Society of Polymer Science 33 (3) 306 - 309 0032-3896 2001/03/15 [Not refereed][Not invited]
  • Selective skeletal rearrangement of bicyclo[n.2.0] ketones to bridged medium-ring compounds
    Kakiuchi, Kiyomi, Morimoto, Tsumoru, Tsutsumi, Ken, Nakano, Tamaki
    Abstracts of Papers, 221st ACS National Meeting, San Diego, CA, United States 2001 [Refereed][Not invited]
  • Optically active methacrylate polymers with high isotacticity and their preparation
    Okamoto, Yoshio, Nakano, Tamaki
    2001 [Refereed][Not invited]
  • Piperidine group-containing methacrylic acid ester, their preparation, and polymers therefrom with high stereoregularity
    Okamoto, Yoshio, Nakano, Tamaki
    2001 [Refereed][Not invited]
  • Nakano, Tamaki, Ueda, Kiyoko, Okamoto, Yoshio
    Journal of Polymer Science, Part A: Polymer Chemistry 39 (10) 1610 - 1614 0887-624X 2001 [Refereed][Not invited]
  • Manufacture of highly syndiotactic vinyl alcohol polymers
    Okamoto, Yoshio, Nakano, Tamaki, Sawamoto, Mitsuo, Kamigaito, Masaki, Nagata, Naohiko, Nagae, Yoshitaka, Yamada, Kazunobu, Terada, Kazutoshi, Otake, Tomiaki, Kanesaka, Junichiro
    2001 [Refereed][Not invited]
  • T Nakano
    KOBUNSHI RONBUNSHU 58 (8) 411 - 426 0386-2186 2001 [Refereed][Not invited]
     
    Methods of chiral induction were found for radical polymerization of 1-phenyldibenzosuberyl methacrylate (PDBSMA) and for those of N-phenyl- and N-cyclohexylmaleimide (PMI and CHMI). PDBSMA gives an almost completely isotactic polymer by conventional radical polymerization; the product is an equimolar mixture of right- and left-handed helices. Helix-sense selection during the radical polymerization of PDBSMA was realized using optically active peroxides as initiators, thiols as chain-transfer agents (CTA), alcohols as solvents, and cobalt (II) complexes as additives. When the first three chiral sources were used, helix-sense selection took place through termination reactions, i.e. primary radical termination or hydrogen transfer from CTA or solvent to the growing radical. Though the chiral induction mechanism of cobalt (II) is not completely clear, the complex seems to interact with the growing radical. Polymers of PMI and CHMI may contain achiral cis- and chiral trans-monomeric units in the main-chain. Polymerization of the two monomers in the presence of an optically active cobalt (II) complex led to optically active polymers. Through an interaction between the cobalt (II) species and growing radical, either (R,R)- or (S,S)- form of the trans-unit may have been produced in excess.
  • K Yamada, A Kajiwara, T Nakano, Y Okamoto
    POLYMER JOURNAL 33 (3) 313 - 316 0032-3896 2001 [Not refereed][Not invited]
  • Y Nagara, K Yamada, T Nakano, Y Okamoto
    POLYMER JOURNAL 33 (7) 534 - 539 0032-3896 2001 [Not refereed][Not invited]
     
    The free-radical polymerization of vinyl acetate (VAc) was carried out in various alcoholic solvents in connection with our recent publication in which we reported that the radical polymerization of VAc in (CF3)(3)COH as a solvent results in a polymer having a high syndiotacticity (r = 72.2%) [K. Yamada, T. Nakano, and Y. Okamoto, Macromolecules, 31, 7598 (1998)]. In this study, (CF3)(2)CHOH. a fluoroalcohol much less expensive than (CF3)(3)COH, was found to have an r-enhancing effect similar to (CF3)(3)COH. The syndiotacticity achieved in this system was up to 70.3%, which is comparable to that during the radical polymerization of vinyl esters in (CF3)3COH. Through the large scale polymerization using (CF3)(2)CHOH as a solvent, syndiotactic PVA (r = 69.2%) was obtained for the characterization of its physical properties. It is noteworthy that the polymerization in (CF3)2CHOH at -78 degreesC smoothly proceeded in spite of the fact that the reaction system was apparently solid.
  • ZHANG Jing, LIU Weihong, NAKANO Tamaki, OKAMOTO Yoshio
    Polymer Journal Society of Polymer Science 32 (8) 694 - 699 0032-3896 2000/08/15 [Not refereed][Not invited]
  • T Nakano, Y Okamoto
    MACROMOLECULAR RAPID COMMUNICATIONS 21 (10) 603 - 612 1022-1336 2000/07 [Refereed][Not invited]
     
    The syntheses of optically active polymers having helical conformation from bulky methacrylates are reviewed focusing on selected topics. The monomers include triphenylmethyl methacrylate and its analogues. Asymmetric anionic polymerization of the monomers gives isotactic, optically active polymers having a helical structure with excess helicity, The isotactic content and the extent of helical-sense excess depend on the monomer structure and the reaction conditions. In the case of methacrylates, completely isotactic and single-handed helical polymers can be produced by asymmetric anionic polymerization (helix-sense-selective polymerization). Asymmetric radical polymerization is also possible for this class of monomer. Some of the helical polymers show chiral recognition ability coward a wide range of racemic compounds. Polymers having main-chain configurational chirality are also discussed.
  • WH Liu, T Nakano, Y Okamoto
    POLYMER 41 (12) 4467 - 4472 0032-3861 2000/06 [Refereed][Not invited]
     
    The polymerization of tert-butyl acrylate (tBA) was performed with triethylaluminum-(-)-sparteine, triethylaluminum-tertiary phosphine, triethylaluminum-n-BuLi and bis(2,6-di-tert-butyl-4-methylphenoxide)methylaluminium-t-BuLi complexes in toluene. The poly (tBA)s obtained with these initiators were rich in syndiotactic diad as observed by H-1 NMR analysis. On the basis of the triad and tetrad stereochemical information of the poly(tBA)s obtained using triethylaluminum-(-)-sparteine and triethylaluminum-n-BuLi, the polymerization reactions were found to obey Bernoullian statistics. Glass transition temperatures of the poly(tBA)s were measured by differential scanning calorimetry (DSC). A syndiotactic poly(tBA) (racemo (r) diad content: 65%) and an isotactic one (r = 19%) exhibited higher glass transition temperature (50 and 43 degrees C, respectively) than an atactic one (r = 50%, T-g = 21 degrees C). (C) 2000 Elsevier Science Ltd. All rights reserved.
  • T Nakano, D Tamada, J Miyazaki, K Kakiuchi, Y Okamoto
    MACROMOLECULES 33 (5) 1489 - 1491 0024-9297 2000/03 [Refereed][Not invited]
  • WH Liu, T Nakano, Y Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 38 (6) 1024 - 1032 0887-624X 2000/03 [Refereed][Not invited]
     
    The free-radical polymerization of 2,2,2-trifluoroethyl acrylate (TFEA), 1,1,1,3,3,3-hexafluoro-2-propyl acrylate (HFiPA) and perfluoro-tert-butyl acrylate (PFtBA) was carried out under various conditions and the stereostructure of the obtained polymers was investigated. Most polymerizations of the three monomers afforded polymers rich in diad syndiotacticity (r) in bulk or in solution; the r-specificity was higher in the HFiPA and PFtBA polymerization than in the TFEA polymerization. Although the tacticity was nearly independent of reaction temperature during the polymerization of TFEA, the r-specificity increased by lowering the reaction tempera -ture during the polymerization of the other two monomers. The polymerization stereochemistry was also affected by the reaction solvents including toluene, tetrahydrofuran, and fluoroalcohols. It was noted that the stereochemistry of the polymerization of HFiPA and PFtBA also depended on the monomer concentration, and a lower monomer concentration led to a higher r-specificity. By optimizing the aforementioned reaction conditions, the poly(HFiPA) having r = 81% (polymerization in tetrahydrofuran at -98 degrees C at [M](o) = 0.2M) and the poly(PFtBA) having r = 77% (polymerization in toluene at -78 degrees C at [M](o) = 0.2M) were obtained. (C) 2000 John Wiley & Sons, Inc.
  • K Yamada, T Nakano, Y Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 38 (1) 220 - 228 0887-624X 2000/01 [Refereed][Not invited]
     
    Free-radical copolymerizations of vinyl acetate (VAc = M-1) and other vinyl esters (= M-2) including vinyl pivalate (VPi), vinyl 2,2-bis(trifluoromethyl)propionate (VF6Pi), and vinyl benzoate (VBz) with fluoroalcohols and tetrahydrofuran (THF) as the solvents were investigated. The fluoroalcohols affected not only the stereochemistry but also the polymerization rate. The polymerization rate was higher in the fluoroalcohols than in THF. The accelerating effect of the fluoroalcohols on the polymerization was probably due to the interaction of the solvents with the ester side groups of the monomers and growing radical species. The difference in the monomer reactivity ratios (r(1), r(2)) in THF and 2,2,2-trifluoroethanol was relatively small for all reaction conditions and for the monomers tested in this work, whereas r(1) increased in the VAc-VF6Pi copolymerization and r(2) decreased in the VAc-VPi copolymerization when perfluorotert-butyl alcohol was used as the solvent. These results were ascribed to steric and monomer-activating effects due to the hydrogen bonding between the monomers and solvents. (C) 2000 John Wiley & Sons, Inc.
  • Manufacture of polyvinyl alcohol with high heterotacticity in branched fluoroalcohol solvents
    Yamada, Kazunobu, Okamoto, Yoshio, Nakano, Tamaki, Sawamoto, Mitsuo, Kitabatake, Kazutsugu, Terada, Kazutoshi, Ida, Hirotsugu, Kano, Yoshiaki, Oki, Hiroyoshi, Okano, Yoshimichi
    Yamada, Kazunobu; Okamoto, Yoshio; Nakano, Tamaki; Sawamoto, Mitsuo; Kitabatake, Kazutsugu; Terada, Kazutoshi; Ida, Hirotsugu; Kano, Yoshiaki; Oki, Hiroyoshi; Okano, Yoshimichi 2000 [Refereed][Not invited]
  • Control of stereoregularity in radical polymerization and manufacture of stereoregular acrylic polymers by the method
    Yamada, Kazunobu, Isobe, Yutaka, Okamoto, Yoshio, Nakano, Tamaki, Sawamoto, Mitsuo, Kitahata, Kazutsugu, Terada, Kazutoshi, Ida, Hirotsugu, Okano, Yoshimichi, Nishimura, Masamichi
    2000 [Refereed][Not invited]
  • Synthesis of single-handed helical polymethacrylates from designed bulky monomers by anionic and free-radical catalyses
    Okamoto, Yoshio, Ueda, Kiyoko, Kinjo, Naotaka, Nakano, Tamaki
    Polymer Preprints 41 (1) 887 - 888 2000 [Refereed][Not invited]
  • Manufacture of optically active crosslinked gel with solvolysis resistance and excellent optical property
    Okamoto, Yoshio, Nakano, Tamaki
    2000 [Refereed][Not invited]
  • Synthesis of single-handed helical polymethacrylates from designed-bulky monomers by anionic and free-radical catalyses
    Okamoto, Yoshio, Ueda, Kiyoko, Kinjo, Naotaka, Nakano, Tamaki
    Book of Abstracts, 219th ACS National Meeting, San Francisco 2000 [Refereed][Not invited]
  • Chiral induction in radical polymerization of maleimide derivatives using optically active cobalt(II) complexes
    Nakano, Tamaki, Tamada, Daisuke, Kakiuchi, Kiyomi, Okamoto, Yoshio
    Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) 41 (2) 1229 - 1230 2000 [Refereed][Not invited]
  • J Zhang, WH Liu, T Nakano, Y Okamoto
    POLYMER JOURNAL 32 (8) 694 - 699 0032-3896 2000 [Refereed][Not invited]
     
    N-Methyl methacrylamide (N-MMAm) was polymerized using radical initiators under various conditions. The triad tacticity of the obtained polymers was determined by 100 MHz C-13 NMR. The polymers were rich in syndiotactic configuration. At a given temperature, the syndiotacticity increased with an increase in solvent polarity. This solvent effect may have connection with the hydrogen bonding interaction among solvent, monomer, and growing species. The fraction of rr triad increased with decreasing polymerization temperature in all solvents. Monomer concentration also affected the stereochemistry of the polymerization. By optimizing conditions, a high rr specificity (rr = 95%) was achieved. Thermal property of the poly(N-MMAm)s with different tacticities was studied by DSC.
  • Okamoto, Yoshio, Yamada, Kazunobu, Nakano, Tamaki
    ACS Symposium Series (768) 57 - 67 2000 [Refereed][Not invited]
  • WH Liu, T Nakano, Y Okamoto
    POLYMER JOURNAL 32 (9) 771 - 777 0032-3896 2000 [Refereed][Not invited]
     
    Free-radical polymerizations of N,N-dimethylacrylamide (DMAA) and N,N-diphenylacrylamide (DPAA) were carried out under various conditions. DMAA gave an isotactic-rich polymer in most cases, whereas DPAA gave a syndiotactic polymer. The polymerization stereochemistry was also affected by reaction solvents including toluene, tetrahydrofuran, and fluoroalcohols. It is notable that the stereochemistry of the polymerization depended on monomer concentration: a lower monomer concentration led to a higher isotacticity for DMAA polymerization and a higher syndiotacticity for DPAA polymerization. This effect was explained by assuming that there exist two types of growing radicals having different stereoselectivities. By optimizing the aforementioned reaction conditions, poly(DMAA) with diad isotacticity im) of 77% (polymerization in toluene at -78 degreesC at [M](o) = 0.1 M) and poly(DPAA) with diad syndiotacticity (r) Of 93% (polymerization in THF at -98 degreesC at [M](o) = 0.22 M) were obtained. Stereoregular poly(methyl acrylate)s were derived from the Doly(DPAA)s. Thermal property of the poly(methyl acrylate)s with different tacticities was studied by DSC.
  • Asymmetric polymerization
    Okamoto, Yoshio, Nakano, Tamaki
    Catalytic Asymmetric Synthesis (2nd Edition) 757 - 796 2000 [Refereed][Not invited]
  • Chiral induction in radical polymerization of maleimide derivatives using optically active cobalt(II) complexes
    Nakano, Tamaki, Tamada, Daisuke, Miyazaki, Jun-ichi, Kakiuchi, Kiyomi, Okamoto, Yoshio
    Abstracts of Papers, 220th ACS National Meeting, Washington, DC, United States 2000 [Refereed][Not invited]
  • Free-radical polymerization
    nakano.tamaki
    Polymer Yearbook (17) 361 - 366 2000 [Refereed][Not invited]
  • Y Isobe, K Yamada, T Nakano, Y Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 38 (Supplement) 4693 - 4703 0887-624X 2000 [Refereed][Not invited]
     
    The free-radical polymerization of methyl methacrylate (MMA), ethyl methacrylate (EMA), isopropyl methacrylate (IPMA), and tert-butyl methacrylate (t-BuMA) was carried out under various conditions to achieve stereoregulation. In the MMA polymerization, syndiotactic specificity was enhanced by the use of fluoroalcohols, including (CF3)(3)COH as a solvent or an additive. The polymerization of MMA in (CFs(3))(3)COH at -98 degreesC achieved the highest syndiotacticity (rr = 93%) for the radical polymerization of methacrylates. Similar effects of fluoroalcohols enhancing syndiotactic specificity were also observed in the polymerization of EMA, whereas the effect was negligible in the IPMA polymerization. In contrast to the polymerizations of MMA and EMA, syndiotactic specificity was decreased by the use of (CF3)(3)COH in the t-BuMA polymerization. The stereoeffects of fluoroalcohols seemed to be due to the hydrogen-bonding interaction of the alcohols with monomers and growing species. The interaction was confirmed by NMR measurements. In addition, in the bulk polymerization of MMA at -78 degreesC, syndiotactic specificity and polymer yield increased even in the presence of a small amount {[(CF3)(3)COH]/[MMA](0) < 1] of (CF3)(3)COH. (C) 2000 John Wiley & Sons, Inc.
  • K Yamada, T Nakano, Y Okamoto
    POLYMER JOURNAL 32 (8) 707 - 710 0032-3896 2000 [Not refereed][Not invited]
  • WH Liu, T Nakano, Y Okamoto
    POLYMER JOURNAL 32 (9) 771 - 777 0032-3896 2000 [Not refereed][Not invited]
     
    Free-radical polymerizations of N,N-dimethylacrylamide (DMAA) and N,N-diphenylacrylamide (DPAA) were carried out under various conditions. DMAA gave an isotactic-rich polymer in most cases, whereas DPAA gave a syndiotactic polymer. The polymerization stereochemistry was also affected by reaction solvents including toluene, tetrahydrofuran, and fluoroalcohols. It is notable that the stereochemistry of the polymerization depended on monomer concentration: a lower monomer concentration led to a higher isotacticity for DMAA polymerization and a higher syndiotacticity for DPAA polymerization. This effect was explained by assuming that there exist two types of growing radicals having different stereoselectivities. By optimizing the aforementioned reaction conditions, poly(DMAA) with diad isotacticity im) of 77% (polymerization in toluene at -78 degreesC at [M](o) = 0.1 M) and poly(DPAA) with diad syndiotacticity (r) Of 93% (polymerization in THF at -98 degreesC at [M](o) = 0.22 M) were obtained. Stereoregular poly(methyl acrylate)s were derived from the Doly(DPAA)s. Thermal property of the poly(methyl acrylate)s with different tacticities was studied by DSC.
  • Y Isobe, K Yamada, T Nakano, Y Okamoto
    MACROMOLECULES 32 (18) 5979 - 5981 0024-9297 1999/09 [Refereed][Not invited]
  • J Wu, T Nakano, Y Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 37 (14) 2645 - 2648 0887-624X 1999/07 [Refereed][Not invited]
     
    Almost optically pure (+)- and (-)-2-fluorophenyl-4-fluorophenyl-2-pyridylmethyl methacrylate (2F4F2PyMA) monomers were obtained by HPLC resolution of the racemic monomer and polymerized with the use of anionic and free-radical initiators. Helix-sense selectivity during the polymerization seemed to be governed mainly by the chirality of the monomer itself, and the polymers obtained by using the complex of N,N'-diphenylethylenediamine monolithium amide with(S)-(+)-1-(2-pyrrolidinylmethyl)-pyrrolidine (PMP) in toluene at -78 degrees C appeared to possess single-handed helical conformation (+)-poly[(-)-2F4F2PyMA], [alpha](365) + 1510 degrees; (-)-poly[(+)-2F4F2PyMA], [alpha](365) - 1610 degrees]. The single-handed helical (+)-poly[(-)-2F4F2PyMA] and (-)-poly[(+)-2F4F2PyM] obtained with the PMP complex exhibited better chiral recognition ability toward trans-stilbene oxide compared with the single-handed helical poly(rac-2F4F2PyMA) prepared previously. (C) 1999 John Wiley & Sons, Inc.
  • K Yamada, T Nakano, Y Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 37 (14) 2677 - 2683 0887-624X 1999/07 [Refereed][Not invited]
     
    Free-radical polymerization of vinyl esters including vinyl propionate (VPr), vinyl isobutylate (ViBu), vinyl 2,2-dimethylbutylate (VDMB), vinyl 2,2-dimethylvalerate (VDMV), vinyl 2,2-bis(trifluoromethyl)propionate (VF6Pi), and vinyl benzoate (VBz) was carried out using fluoroalcohols as solvents, and the tacticity of the obtained polymers was determined by NMR analysis of the produced poly(vinyl alcohol) (PVA). The polymerization of VPr, ViBu, VDMB, and VDMV, which are bulkier than VAc, in fluoroalcohols afforded polymers rich in heterotacticity (up to mr = 61%) similar to that of vinyl pivalate (VPi) whereas VAc is known to give a syndiotactic polymer under the reaction conditions used here. The polymerization of VF6Pi, which is the bulkiest among the monomers used in this study, gave a polymer rich in syndiotacticity in bulk and in fluoroalcohols regardless of the structure of the solvents. On the other hand, the polymerization of VBz in fluoroalcohols gave olymers with a higher isotacticity (up to mm = 33%) than bulk polymerization. Thus the monomer structure strongly affected the stereochemistry of the free-radical polymerization of vinyl esters in fluoroalcohols. (C) 1999 John Wiley & Sons, Inc.
  • YAMADA Kazunobu, NAKANO Tamaki, OKAMOTO Yoshio
    高分子 48 (7) 0454-1138 1999/07/01 [Not refereed][Not invited]
  • T Nakano, Y Satoh, Y Okamoto
    REACTIVE & FUNCTIONAL POLYMERS 40 (2) 135 - 141 1381-5148 1999/05 [Refereed][Not invited]
     
    The reaction of diphenyl-3-pyridylmethyl and 1-(3-pyridyl)dibenzosuberyl methacrylates with CH3I in CHCl3 at 35 degrees C for 24 h lead to quantitative quaternization of pyridyl group while the reaction using diphenyl-2-pyridylmethyl and 1-(2-pyridyl)dibentosuberyl methacrylates gave only low degree of quaternization. Single-handed helical poly(diphenyl-3-pyridylmethyl) and poly[1-(3-pyridyl)dibenzosuberyl methacrylate] were also quantitatively quaternized with CH3I under the above reaction conditions: the former polymer appeared to lose its helical conformation and the chiroptical properties through the reaction while the conformation of the latter polymer seems to sun;ive the quaternization process. The latter polymer quantitatively reacted with decyl and octadecyl iodides in a CHCl3-DMSO mixture at 55 degrees C to give hairy rod molecules. (C) 1999 Elsevier Science B.V. All rights reserved.
  • T Nakano, Y Okamoto
    MACROMOLECULES 32 (7) 2391 - 2393 0024-9297 1999/04 [Refereed][Not invited]
  • Stereoregulation in free-radical polymerizaion of methacrylates
    Okamoto, Yoshio, Nakano, Tamaki, Yamada, Kazunobu, Isobe, Yutaka
    Book of Abstracts, 217th ACS National Meeting, Anaheim, Calif 1999 [Refereed][Not invited]
  • Stereoregulation in free-radical polymerization of methacrylates
    Okamoto, Yoshio, Nakano, Tamaki, Yamada, Kazunobu, Isobe, Yutaka
    Polymeric Materials Science and Engineering (80) 83  1999 [Refereed][Not invited]
  • Optically active methacrylate ester polymers, their preparation, and optical resolution agents
    Okamoto, Yoshio, Nakano, Tamaki
    1999 [Refereed][Not invited]
  • (Halophenyl)pyridylmethyl methacrylates, their manufacture, optical resolution, and manufacture of their polymers as optical resolution agents
    Okamoto, Yoshio, Nakano, Tamaki, Wu, Jian
    1999 [Refereed][Not invited]
  • Manufacture of highly syndiotactic poly(vinyl alcohol)
    Yamada, Kazunobu, Okamoto, Yoshio, Nakano, Tamaki, Sawamoto, Mitsuo, Nakajima, Hiroshi, Terada, Kazutoshi, Ita, Hirotsugu, Asahi, Tetsuya, Oki, Akiyoshi, Okano, Yoshimichi
    1999 [Refereed][Not invited]
  • Manufacture of poly(vinyl alcohols) with enhanced syndiotacticity
    Yamada, Kazunobu, Okamoto, Yoshio, Nakano, Tamaki, Sawamoto, Mitsuo, Nakajima, Hiroshi, Terada, Kazutoshi, Ida, Hirotsugu, Asahi, Tetsuya, Oki, Yoshiki, Okano, Yoshimichi
    1999 [Refereed][Not invited]
  • Yamada, Kazunobu, Nakano, Tamaki, Okamoto, Yoshio
    Kobunshi 48 (7) 512  1999 [Refereed][Not invited]
  • Stereochemistry in radical polymerization of vinyl esters
    Okamoto, Yoshio, Nakano, Tamaki, Yamada, Kazunobu
    Book of Abstracts, 218th ACS National Meeting, New Orleans 1999 [Refereed][Not invited]
  • Stereochemistry in radical polymerization of vinyl esters
    Okamoto, Yoshio, Nakano, Tamaki, Yamada, Kazunobu
    Polymer Preprints 40 (2) 299 - 300 1999 [Refereed][Not invited]
  • Construction and control of helix structure
    Nakano, Tamaki
    Kagaku 54 (11) 65 - 66 1999 [Refereed][Not invited]
  • WH Liu, T Nakano, Y Okamoto
    POLYMER JOURNAL 31 (5) 479 - 481 0032-3896 1999 [Not refereed][Not invited]
  • T Nakano, N Kinjo, Y Hidaka, Y Okamoto
    POLYMER JOURNAL 31 (5) 464 - 469 0032-3896 1999 [Not refereed][Not invited]
     
    (+/-)-10.11-O-Isopropylidene-trans-10,11-dihydroxy-5-phenyl-10,11-dihydro-5H-dibenzo[a,d]cycloheptene- 5-yl methacrylate (IDPDMA) was synthesized and resolved into an optically pure form by chiral HPLC. Anionic polymerization of IDPDMA was carried out using the complexes of N,N'-diphenylethylenediamine monolithium amide (DPEDA-Li) with (+)-1-(2-pyrrolidinylmethyl)pyrrolidine. (+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane, and (-)-sparteine in toluene at - 78 degrees C or using DPEDA-Li in tetrahydrofuran at - 78 degrees C. The polymers obtained from the racemic monomer using the chiral initiators and the polymer obtained from (+)-monomer under the achiral condition appeared to have a helical conformation with excess helicity. The polymerizations of (+/-)-IDPDMA using the chiral initiators were enantiomer-selective: (+)-monomer was preferentially polymerized. Free-radical polymerization of optically active IDPDMA having various enantiomeric excesses using alpha,alpha-azobisisobutyronitrile in toluene at 60 degrees C gave almost completely isotactic polymers which probably had a helical conformation with excess helicity. Enantiomer selection was also confirmed in the radical polymerization.
  • K Yamada, T Nakano, Y Okamoto
    MACROMOLECULES 31 (22) 7598 - 7605 0024-9297 1998/11 [Refereed][Not invited]
     
    Solvent effects on the stereochemistry of free radical polymerization of vinyl acetate (VAc) and vinyl pivalate (VPi) were investigated. In the polymerization of VAc, an alcoholic solvent with a smaller pK(a) and higher bulkiness afforded a polymer having a higher syndiotacticity. The polymerization of VAc in perfluoro-tert-butyl alcohol ((CF3)(3)COH) at -78 degrees C led to a diad syndiotacticity r of 72%, which is the highest for the radical polymerization of vinyl esters. On the other hand, the polymerization of VPi in fluoroalcohol at a low temperature afforded a polymer rich in heterotacticity (up to mr = 61%). Synthesis of a heterotactic homopolymer by the free radical polymerization of monosubstituted vinyl monomers is unprecedented. The stereochemical effects observed in this study may be due to hydrogen-bond interaction between the fluoroalcohol molecules and the ester groups of the vinyl ester monomer and the side chain of the growing polymer, Mechanisms of stereoregulation were proposed.
  • J Wu, T Nakano, Y Okamoto
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 36 (12) 2013 - 2019 0887-624X 1998/09 [Refereed][Not invited]
     
    A novel racemic methacrylate, (2-fluorophenyl)( 4-fluorophenyl)( 2-pyridyl)-methyl methacrylate(1) (2F4F2PyMA), was synthesized and polymerized with chiral complexes of N,N'-diphenylethylenediamine monolithium amide (DPEDA-Li) with (-)-sparteine (Sp), (2S, 3S)-(+)-2,3-dimethoxy-1,4-bis(dimethylamino)bu (DDB), and (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine (PMP) in toluene at -78 degrees C. The monomer showed higher resistance against methanolysis compared with triphenylmethyl methacrylate (TrMA) and several other analogues. In the asymmetric anionic polymerization of 2F4F2PyMA, PMP was found to be a more effective chiral ligand than DDB and Sp and gave quantitatively an optically active polymer with nearly perfect isotacticity. Enantiomer selection was observed in the polymerization of racemic 2F4F2PyMA with the chiral lithium complexes. Chiral recognition ability of the optically active poly( 2F4F2PyMA) was examined by an enantioselective adsorption experiment. (C) 1998 John Wiley & Sons, Inc.
  • K Yamada, T Nakano, Y Okamoto
    PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES 74 (3) 46 - 49 0386-2208 1998/03 [Refereed][Not invited]
     
    The free-radical polymerization of vinyl acetate (VAc) was carried out in various alcoholic solvents. Fluoroalcohols with a lower pKa and higher bulkiness were effective in enhancing the syndiotactic specificity of the polymerization. The polymerization of VAc in perfluoro-tert-butyl alcohol ((CF3)(3)COH) at -78 degrees C led to a dyad syndiotacticity of 72%, which is the highest value reported for the radical polymerization of vinyl esters. Hydrogen-bonding between the acetyl groups of VAc and polymer and the fluoroalcohol molecule may be responsible for the enhancement of the syndiotactic specific propagation.
  • Nakano, Tamaki, Okamoto, Yoshio
    ACS Symposium Series 685 (ACS Symposium Series) 451 - 462 1998 [Refereed][Not invited]
  • Stereospecific polymerization process of methacrylic acid or their derivatives using amine derivatives
    Okamoto, Yoshio, Nakano, Tamaki
    1998 [Refereed][Not invited]
  • Nakano, Tamaki, Hidaka, Yasuaki, Okamoto, Yoshio
    Polymer Journal 30 (7) 596 - 600 0032-3896 1998 [Refereed][Not invited]
  • T Nakano, Y Satoh, Y Okamoto
    POLYMER JOURNAL 30 (8) 635 - 640 0032-3896 1998 [Refereed][Not invited]
     
    1-(3-Pyridyl)dibenzosuberyl methacrylate was synthesized and polymerized using the complexes of N,N'-diphenylethylenediamine monolithium amide with (+)-1-(2-pyrrolidinylmethyl)pyrrolidine, (+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane, and (-)-sparteine in toluene at -78 degrees C. The polymers obtained by the helix-sense-selective anionic polymerization were highly isotactic and exhibited large dextrorotation based on single-handed helical conformation. Free-radical polymerization in toluene with (iso-PrOCOO)(2) at 40 degrees C and with alpha,alpha'-azobisisobutyronitrile at 60 degrees C gave nearly perfectly isotactic polymers. The optically active polymer exhibited chiral recognition ability toward trans-stilbene oxide and Triiger's base as revealed by chiral adsorption experiments.
  • K Yamada, T Nakano, Y Okamoto
    POLYMER JOURNAL 30 (8) 641 - 645 0032-3896 1998 [Refereed][Not invited]
     
    Radical polymerization of vinyl pivalate (VPi), vinyl trifluoroacetate (VTFAc), vinyl 2,2-bis(trifluoromethyl)propionate (1), vinyl 5H-octafluorovalerate (2), vinyl 7H-dodecafluoroheptanoate (3), and vinyl 9H-hexadecafluorononanoate (4) was carried out and the tacticity of the resulting polymers was determined by H-1 or C-13 NMR analysis of poly(vinyl alcohol) (PVA) derived from the original polymers. In the bulk polymerization at 60 degrees C, the order of diad syndiotacticity of the polymers was poly(VTFAc) (57%) <poly(VPi) (60%) <poly-2, poly-3, poly-4 (61-62%) < poly-1 (65%), suggesting that steric and electrostatic effects of the fluorine-containing side groups of monomers influence the syndiotactic specificity of propagation reaction. A syndiotacticity of 69% was achieved by solution polymerization of 1 in tetrahydrofuran at 0 degrees C. This is the highest syndiotacticity reported for the radical polymerization of vinyl esters at 0 degrees C or higher temperatures. The difference of activation enthalpy (Delta H double dagger) and activation entropy (Delta S double dagger) between isotactic and syndiotactic propagations in bulk polymerization of 1 were estimated to be 460 cal mol(-1) and 0.2 cal deg(-1) mol(-1), respectively. Solvolysis rates of the vinyl esters and their polymers were also examined.
  • T Nakano, KI Makita, Y Okamoto
    POLYMER JOURNAL 30 (8) 681 - 683 0032-3896 1998 [Refereed][Not invited]
  • T Nakano, Y Hidaka, Y Okamoto
    POLYMER JOURNAL 30 (7) 596 - 600 0032-3896 1998 [Not refereed][Not invited]
     
    Polymerization of 9-phenylfluoren-9-yl methacrylate was carried out aiming at obtaining highly isotactic, single-handed helical polymers using the complexes of N,N'-diphenylethylenediamine monolithium amide with (-)-sparteine, (+)-1-(2-pyrroiidinylmethyl)pyrrolidine, and (+)-2.3-dimethoxy-1,4-bis(dimethylamino)butane. Although the isotacticity (nun = 55-46%) and specific rotation ([alpha](365) -54- + 119 degrees) of the obtained polymers were much lower than those of known single-handed helical polymethacrylates, the poly(methyl methacrylate) (PMMA) derived from the obtained polymers exhibited rather high optical activity (Cal,cs -44--11 degrees) for a polymer which does not take any stable, chiral conformation. The optical activity of the PMMA was attributed to cofigurational chirality of the main chain.
  • K Yamada, T Nakano, Y Okamoto
    POLYMER JOURNAL 30 (8) 641 - 645 0032-3896 1998 [Not refereed][Not invited]
     
    Radical polymerization of vinyl pivalate (VPi), vinyl trifluoroacetate (VTFAc), vinyl 2,2-bis(trifluoromethyl)propionate (1), vinyl 5H-octafluorovalerate (2), vinyl 7H-dodecafluoroheptanoate (3), and vinyl 9H-hexadecafluorononanoate (4) was carried out and the tacticity of the resulting polymers was determined by H-1 or C-13 NMR analysis of poly(vinyl alcohol) (PVA) derived from the original polymers. In the bulk polymerization at 60 degrees C, the order of diad syndiotacticity of the polymers was poly(VTFAc) (57%) <poly(VPi) (60%) <poly-2, poly-3, poly-4 (61-62%) < poly-1 (65%), suggesting that steric and electrostatic effects of the fluorine-containing side groups of monomers influence the syndiotactic specificity of propagation reaction. A syndiotacticity of 69% was achieved by solution polymerization of 1 in tetrahydrofuran at 0 degrees C. This is the highest syndiotacticity reported for the radical polymerization of vinyl esters at 0 degrees C or higher temperatures. The difference of activation enthalpy (Delta H double dagger) and activation entropy (Delta S double dagger) between isotactic and syndiotactic propagations in bulk polymerization of 1 were estimated to be 460 cal mol(-1) and 0.2 cal deg(-1) mol(-1), respectively. Solvolysis rates of the vinyl esters and their polymers were also examined.
  • NAKANO Tamaki, TANIGUCHI Kyoichi, OKAMOTO Yoshio
    Polymer Journal Society of Polymer Science 29 (6) 540 - 544 0032-3896 1997/06/15 [Not refereed][Not invited]
  • Nakano, Tamaki
    Kobunshi 46 (2) 81  1997 [Refereed][Not invited]
  • Stereochemical control of free-radical polymerization of vinyl monomers.
    Nakano, Tamaki, Ishigaki, Y, Matsuda, A, Okamoto, Yoshio
    Polymer Preprints 38 (1) 764 - 765 1997 [Refereed][Not invited]
  • T Nakano, K Taniguchi, Y Okamoto
    POLYMER JOURNAL 29 (6) 540 - 544 0032-3896 1997 [Refereed][Not invited]
     
    Diphenyl-3-pyridylmethyl methacrylate was synthesized and polymerized using the complexes of N,N'-diphenylethylenediamine monolithium amide with (+)-1-(2-pyrrolidinylmethyl)pyrrolidine (+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane, and (-)-sparteine in toluene at -78 degrees C (helix-sense-selective polymerization). The obtained polymers were highly isotactic and exhibited large dextrorotation based on helical conformation with excess single-handed helicity. Free radical polymerization with (iso-PrOCOO)(2) in toluene at 40 degrees C also gave an isotactic polymer (mm similar to 74%). The optically active polymer exhibited chiral recognition ability toward several racemic compounds including hexahelicene, trans-stilbene oxide, and binaphthyl derivatives when adsorbed on macro porous silica gel and used as a stationary phase for high-performance liquid chromatography (HPLC).
  • Radical polymerization of (meth)acrylic acid esters in presence of transition metal complexes
    Okamoto, Yoshio, Nakano, Tamaki
    1997 [Refereed][Not invited]
  • Y Okamoto, T Nakano, S Habaue, K Shiohara, K Maeda
    JOURNAL OF MACROMOLECULAR SCIENCE-PURE AND APPLIED CHEMISTRY A34 (10) 1771 - 1783 1060-1325 1997 [Refereed][Not invited]
     
    Asymmetric syntheses of optically active polymethacrylate, polyacrylate, polyacrylamide, and polyisocyanate with helical conformation and their chiral recognition abilities are described. 1-Phenyldibenzosuberyl methacrylate (PDBSMA) gave a purely one-handed-helical, optically active polymer([alpha](365) + 1670 similar to + 1780 degrees) with almost perfectly isotactic structure by anionic polymerization using optically active initiators. Radical polymerizations of PDBSMA using chiral initiators, chain transfer agents, and additives also afforded optically active polymers with a prevailing one-handed helicity. Triphenylmethyl acrylate yielded an optically active, helical polymer ([alpha](365)+ 102 degrees) having a dyad isotacticity of 70% using an optically active anionic initiator. Although the polyacrylate demonstrated chiral recognition ability as a chiral stationary phase for HPLC, the ability was low mainly because of the low degree of one-handedness. N-(3 -Chlorophenyl)-N-phenylacrylamide gave an optically active, helical polymer ([alpha](365) - 343 degrees) in the asymmetric anionic polymerization; the polymer had a dyad tacticity of 77%. Optically active polyisocyanates with a predominantly one-handed helical conformation were prepared in homo and co-polymerization of optically active phenyl isocyanate derivative. These polyisocyanates showed the ability to discriminate enantiomers in solution.
  • T Nakano, Y Shikisai, Y Okamoto
    POLYMER JOURNAL 28 (1) 51 - 60 0032-3896 1996 [Refereed][Not invited]
     
    The helix-sense-selective free radical polymerization of 1-phenyldibenzosuberyl methacrylate was carried out in toluene at 40 or 50 degrees C under chiral reaction conditions which involve (1) (-)-dimenthyl peroxydicarbonate and (-)-o-carbomenthoxybenzoyl peroxide as an initiator, (2) (-)- and (+)-menthol, (+)-neomenthol, and (+)-1-phenyl-1-butanol as a reaction solvent (additive), (3) (+)- and (-)-neomenthanethiol and (-)-menthanethiol as a chain transfer agent, and (4) (-)-phenyl-2-pyridyl-o-tolylmethyl methacrylate as a comonomer for copolymerization. Highly isotactic, optically active polymers having a helical conformation with excess light- or left-handed helicity were obtained, In the polymerization using an optically active initiator, helix-sense-selection appeared to lake place through primary radical termination. The helix-sense-selection in the polymerization in the presence of the optically active alcohols and thiols was found to involve chain transfer process. In polymerization using thiols, both hydrogen transfer reaction from a thiol to a growing radical and initiation by thio radical were suggested to be responsible for the selectivity. In the case of the copolymerization, the optically active monomeric unit incorporated into the polymer chain was found to induce excessive single handed helicity where the selected helicity reversed depending on the amount of the incorporated optically active monomeric units.
  • Stereospecific and helix-sense-selective radical polymerization of methacrylates
    Okamoto, Yoshio, Nakano, Tamaki
    Polymer Preprints 37 (2) 444 - 445 1996 [Refereed][Not invited]
  • Optical resolution agents consisting of optically active methacrylate polymers
    Okamoto, Yoshio, Nakano, Tamaki
    1996 [Refereed][Not invited]
  • Helical polymers: synthesis, conformation, and function
    Okamoto, Yoshio, Nakano, Tamaki, Habaue, Shigeki
    New Macromolecular Architecture and Functions, Proceedings of the OUMS'95, 2nd, Toyonaka, Japan 89 - 98 1996 [Refereed][Not invited]
  • T NAKANO, Y SHIKISAI, Y OKAMOTO
    PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES 71 (8) 251 - 255 0386-2208 1995/10 [Refereed][Not invited]
     
    Free radical polymerization of 1-phenyldibenzosuberyl methacrylate was carried out in toluene at 40 or 50 degrees C under chiral reaction conditions based on the use of (-)-dimenthyl peroxydicarbonate as an initiator, (-)- and (+)-menthol as a reaction solvent (additive), and (+)- and (-)-neomenthanethiol as a chain transfer agent. The obtained polymers had a highly isotactic and helical structure; there was an excess of right- or left-handed helicity by the influence of the above chiral materials and consequently, the polymers were optically active. The mechanism of chiral induction for the polymerization using the chiral initiator involved helix-sense-selective primary radical termination, i.e., the reaction between a polymer radical and an initiator radical. In the polymerization using menthol and neomenthanethiol, hydrogen transfer from these chiral compounds to the growing radical appeared to take place in a helix-sense-selective manner.
  • Y OKAMOTO, M NISHIKAWA, T NAKANO, E YASHIMA, K HATADA
    MACROMOLECULES 28 (14) 5135 - 5138 0024-9297 1995/07 [Refereed][Not invited]
     
    Optically active phenyl-2-pyridyl-o-tolylmethyl methacrylate (PPyoTMA) having Various enantiomeric excesses was polymerized with diisopropyl peroxydicarbonate in toluene at 40 degrees C. Isotactic polymers were obtained. The polymers showed large optical rotations which are opposite in sign to the rotation of the starting monomer and the optical activity was higher than expected from the enantiomeric purity of the monomeric units in the polymer, indicating that a right- or left-handed helix was formed in excess from the steric effect of the chiral side group. Copolymerization of PPyoTMA with triphenylmethyl methacrylate (TrMA) also gave optically active, isotactic polymers; the phenyl-2-pyridyl-o-tolylmethyl group is also effective in inducing an excess of a single-handed helix consisting of TrMA monomeric sequences. Copolymerization with MMA gave atactic polymers showing much smaller optical activity than that of the copolymers with TrMA.
  • T NAKANO, DY SOGAH
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 117 (1) 534 - 535 0002-7863 1995/01 [Refereed][Not invited]
  • K MAEDA, M MATSUDA, T NAKANO, Y OKAMOTO
    POLYMER JOURNAL 27 (2) 141 - 146 0032-3896 1995 [Refereed][Not invited]
     
    Oligomerization of m-methylphenyl isocyanate (mMePI) with lithium amide of (S)-(-)-2-(methoxymethyl)pyrrolidine (MMP) was carried out to obtain oligomers containing a chiral residue at the initial chain end (alpha-end). The oligomers of degree of polymerization (DP) less than eighteen were separated in terms of DP and the specific rotation of each oligomer was estimated. The oligomers showed the high optical rotation which is ascribed to the structure prevailing in one-screw sense. The specific rotation of the oligomers increased up to DP of twelve and then decreased with an increase in DP. This suggests that the DP corresponding to the average persistence length of single handed helix may be larger than twelve. The specific rotation of the polymers was inversely proportional to the molecular weight. The optical activity of the polymer greatly increased with a decrease in temperature, whereas that of the trimer was not influenced by temperature.
  • Y OKAMOTO, T NAKANO, Y SHIKISAI, M MORI
    MACROMOLECULAR SYMPOSIA 89 479 - 488 1022-1360 1995/01 [Refereed][Not invited]
     
    Stereospecific and asymmetric (helix-sense-selective) polymerization of 1-phenyldibenzosuberyl methacrylate (PDBSMA) was performed with radical and anionic initiators. A highly isotactic polymer having triad isotacticity greater than 97% was obtained by radical polymerization with (i-PrOCOO)(2) at 40 degrees C. The radical polymerization of PDBSMA in (+)- and (-)-menthol gave (-)- and (+)-polymers, respectively, whose optical activity is ascribed to the prevailing one-handed helical conformation of a polymer chain. The radical copolymerization of PDBSMA with a small amount of an optically active monomer, (+)-phenyl-2-pyridyl-o-tolylmethyl methacrylate, afforded an optically active copolymer with the prevailing one-handed helical structure of PDBSMA sequences. Asymmetric anionic polymerization of PDBSMA was carried out with the complex of N, N'-diphenylethylenediamine monolithium amide and a chiral ligand, (+)-1-(2-pyrrolidinylmethyl)pyrrolidine in toluene at -78 degrees C. The obtained polymer was highly isotactic and optically active due to nearly 100% one-handed helical structure.
  • Toward stereochemical control in silicon-mediated polymerizations
    Sogah, Dotsevi Y, Shen, Jianzhong, Nakano, Tamaki
    Book of Abstracts, 210th ACS National Meeting, Chicago 1995 [Refereed][Not invited]
  • T NAKANO, Y OKAMOTO, K HATADA
    POLYMER JOURNAL 27 (9) 892 - 903 0032-3896 1995 [Not refereed][Not invited]
     
    Asymmetric anionic polymerization and oligomerization of triphenylmethyl methacrylate (TrMA) were carried out with the complexes of (-)-sparteine (Sp) with 9-methyl-9-fluorenyllithium (MeFlLi) and 9-ethyl-9-fluorenyllithium in toluene at -78 degrees C in conjunction with the polymerization of TrMA with Sp-9-fluorenyllithium (FlLi) complex. As well as Sp-FlLi complex, Sp-MeFlLi complex gave an optically active ([alpha](D) +360 degrees), highly isotactic polymer with one-handed helical conformation; the polymer had a higher molecular weight than that obtained by Sp-FILi under the same reaction conditions. The oligomers obtained at the feed ratio of monomer to initiator of two, three, and five were converted to oligo(methyl methacrylate) [oligo(MMA)]; the oligo(MMA)s were first separated in terms of degree of polymerization and then into diastereomers. The dimer meso (m) and raceme (r) and the trimer mm and mr were resolved into enantiomers to determine the ratio of isomers for each oligomer. On the basis of the change in isomer content of the dimer with the change in the feed ratio of monomer to initiator, it was concluded that the dimer anion having S absolute configuration is more active toward TrMA monomer than that having R configuration in both the systems with MeFlLi and EtFlLi in contrast to the reaction with Sp-FlLi where the R-dimer anion is more active. The stereochemistry in the propagation of a trimer anion to a tetramer anion and thereafter appeared similar to the reaction system with Sp-FlLi where -RRR- isomers predominantly propagate, The predominant propagation of the S-dimer anion results in a larger amount of the isomeric anions which do not propagate to the optically active polymer.
  • T NAKANO, Y OKAMOTO, K HATADA
    POLYMER JOURNAL 27 (9) 882 - 891 0032-3896 1995 [Not refereed][Not invited]
     
    Oligomerization of triphenylmethyl methacrylate (TrMA) was carried out with the complex of 9-fluorenyllithium and (-)-sparteine in toluene at -78 degrees C. The reaction was terminated by methylation using methyl iodide and methyl iodide-d(3) or by protonation using methanol, butanol, 2-propanol, and t-butanol. The resulting oligomers were converted to oligo(methyl methacrylate) [oligo(MMA)]; the oligomers were first separated in terms of degree of polymerization and then into diastereomers. The individual diastereomers were resolved into enantiomers and the ratio of isomers was determined for each oligomer. Methylation with methyl iodide-d(3) of dimer anion occurred stereoselectively. Protonation stereochemistry was strongly affected by stereostructure of the protonating alcohols. The effect of alcohol was more obvious for the anions which were less active toward TrMA monomer.
  • Y OKAMOTO, T NAKANO
    CHEMICAL REVIEWS 94 (2) 349 - 372 0009-2665 1994/03 [Refereed][Not invited]
  • Y OKAMOTO, M MATSUDA, T NAKANO, E YASHIMA
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 32 (2) 309 - 315 0887-624X 1994/01 [Refereed][Not invited]
     
    The asymmetric anionic polymerization of o-, m-, and p-methylphenyl isocyanates, p-methoxyphenyl isocyanate, p-chlorophenyl isocyanate, 2,6- and 3,4-dimethylphenyl isocyanates, and 1-naphthyl isocyanate was carried out using chiral anionic initiators such as the lithium salts of (-)-menthol, (-)-( 2-methoxymethyl) pyrrolidine, and (+)-1-(2-pyrrolidinylmethyl) pyrrolidine. Although o-methylphenyl isocyanate gave an insoluble polymer and 2,6-dimethylphenyl isocyanate afforded no polymer, the other monomers gave soluble polymers, which showed optical activity due to the prevailing helicity of the polymer chain induced by chiral initiator residues attached to the a-end of the polymer chain. The molecular mechanics conformational calculation for a tetramer of m-methylphenyl isocyanate sup ported the helical conformation of the main chain. The optical rotation of the polymers depended significantly on temperature. (C) 1994 John Wiley & Sons, Inc.
  • Optically active methacrylic ester polymers
    Okamoto, Yoshio, Nakano, Tamaki
    1994 [Refereed][Not invited]
  • Helix-sense-selective polymerization of methacrylate and conformational characteristics of the polymers
    Okamoto, Yoshio, Nakano, Tamaki
    Prog. Pac. Polym. Sci. 3, Proc. Pac. Polym. Conf., 3rd 111 - 122 1994 [Refereed][Not invited]
  • Cyclopolymerization of 2,2'-bis(methacryloyloxymethyl)-1,1'-binaphthyl. Comparison of group transfer (GTP), anionic, and free radical polymerizations
    Nakano, Tamaki, Sogah, Dotsevi Y
    Polymer Preprints 35 (2) 862 - 863 1994 [Refereed][Not invited]
  • Helix-sense-selective polymerization of bulky methacrylates with radical and anionic initiators
    Okamoto, Yoshio, Nakano, Tamaki, Shikisai, Yoshifumi, Matsuda, Akihiro
    Polymer Preprints 35 (2) 591 - 592 1994 [Refereed][Not invited]
  • CY REN, CF CHEN, F XI, T NAKANO, Y OKAMOTO
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 31 (11) 2721 - 2728 0887-624X 1993/10 [Refereed][Not invited]
     
    A novel monomer, phenyl[bis(2-pyridyl)]methyl methacrylate (PB2PyMA), was synthesized. The solvolysis rate of PB2PyMA measured in CDCl3-CD3OD[1/1 (v/v)] by H-1-NMR spectroscopy at 35-degrees-C was much smaller than those of triphenylmethyl methacrylate (TrMA) and diphenyl-2-pyridylmethyl methacrylate (D2PyMA). PB2PyMA was anionically polymerized with the complexes of organolithiums with (-)-sparteine (Sp), (S,S)-(+)-and (R,R)-(-)-2,3-dimethoxy-1,4-bis(dimethylamino) butanes [(+)- and (-)-DDB ], and (S)-(+)-1-(2-pyrrolidinylmethyl) pyrrolidine (PMP) in toluene at low temperature. The polymers obtained with Sp and DDB complexes showed low optical activity. PMP complexes, particularly that with N,N'-diphenylethylenediamine monolithium amide, were effective in synthesizing a polymer of high optical rotation ([alpha]365(25) approximately +1350-degrees) which was comparable to those of poly (TrMA) and poly (D2PyMA) with one-handed helical structure. The optical rotation of poly (PB2PyMA) in a mixture of CHCl3 and 2,2,2-trifluoroethanol (9/1, v/v) slowly decreased with time. Optically active poly (PB2PyMA) coated on macroporous silica gel was able to resolve racemic compounds as a chiral stationary phase for high-performance liquid chromatography. (C) 1993 John Wiley & Sons, Inc.
  • T NAKANO, T HASEGAWA, Y OKAMOTO
    MACROMOLECULES 26 (20) 5494 - 5502 0024-9297 1993/09 [Refereed][Not invited]
     
    2-[4-(4'-Methoxyphenyl)phenoxy]ethyl, 3-[4-(4'-methoxyphenyl)phenoxy]propyl, 4-[4-(4'-methoxyphenyl)phenoxy]butyl, 5-[4-(4'-methoxyphenyl)phenoxy]pentyl, and 6-[4-(4'-methoxyphenyl)-phenoxy]hexyl methacrylates were synthesized and polymerized. Anionic polymerization of these monomers was carried out with tert-butylmagnesium bromide in toluene, chloroform, and tetrahydrofuran at low temperature, and radical polymerization was conducted with alpha,alpha'-azobis(isobutyronitrile) in toluene at 60-degrees-C. Highly isotactic (mm 90-97%) and syndiotactic (rr 79-86%) polymers were obtained by anionic polymerization in chloroform and tetrahydrofuran, respectively, and polymers rich in syndiotacticity (rr 56-66%) were obtained by radical polymerization. Thermal properties and liquid crystallinities of the polymers depended greatly on both the tacticity of the main chain and the length of the methylene chain (spacer) in the side group. These observations were interpreted in terms of zigzag (alt-trans) and helical conformations of the main chain of syndio- and isotactic polymers, respectively, and the all-trans conformation of the spacer chain.
  • 岡本 佳男, 中野 環
    化学工業 化学工業社 44 (7) 560 - 566 0451-2014 1993/07 [Not refereed][Not invited]
  • T NAKANO, M MORI, Y OKAMOTO
    MACROMOLECULES 26 (4) 867 - 868 0024-9297 1993/02 [Refereed][Not invited]
  • Y OKAMOTO, M MATSUDA, T NAKANO, E YASHIMA
    POLYMER JOURNAL 25 (4) 391 - 396 0032-3896 1993 [Refereed][Not invited]
     
    Anionic polymerization of 3-phenylpropyl, 4-phenylbutyl, and butyl isocyanates was carried out with chiral anionic initiators such as tert-butyllithium-(-)-sparteine complex (t-BuLi-(-)-Sp), lithium (-)-menthoxide, and (+)-1-(2-pyrrolidinylmethyl)pyrrolidine lithium amide. The t-BuLi-(-)-Sp did not afford optically active polymers. However, the alkoxide and amide gave optically active polymers for 4-phenylbutyl and butyl isocyanates. The optical activities are probably based on the prevailing helicity of the polymer chains induced by chiral initiator residues attaching to an alpha-end group of the polymer chain. The optical rotation of the polymers depended greatly on molecular weight and temperature.
  • Catalysts for chiral polymerization
    Okamoto, Yoshio, Nakano, Tamaki
    Kagaku Kogyo 44 (7) 560 - 566 1993 [Refereed][Not invited]
  • Synthesis of helical polymers
    Nakano, Tamaki, Okamoto, Yoshio
    Kagaku, Zokan 123 95 - 100 1993 [Refereed][Not invited]
  • Synthesis and stereomutation of optically active polymers with helical conformation
    Nakano, Tamaki, Okamoto, Yoshio
    Kikan Kagaku Sosetsu 18 129 - 136 1993 [Refereed][Not invited]
  • Studies on synthesis, structure, and application of optically active polymers with helical conformation
    Okamoto, Yoshio, Nakano, Tamaki
    Asahi Garasu Zaidan Josei Kenkyu Seika Hokoku 17 - 24 1993 [Refereed][Not invited]
  • T NAKANO, Y OKAMOTO, K HATADA
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 114 (4) 1318 - 1329 0002-7863 1992/02 [Refereed][Not invited]
     
    Asymmetric oligomerization of triphenylmethyl methacrylate (TrMA) was carried out with complexes of 9-fluorenyllithium and chiral ligands in toluene at -78-degrees-C, and the oligomers obtained were converted into methyl esters. The resulting oligo(methyl methacrylate)s were first fractionated by gel permeation chromatography in terms of degree of polymerization and further separated into diastereomers and optical isomers by high-performance liquid chromatography. The distribution of oligomers and the ratio of isomers in each oligomer gave important information on the mechanism of the asymmetric (helix sense selective) polymerization of TrMA. The reactivity of each oligomer anion depended greatly on its degree of polymerization and stereostructure. The oligomer anions whose asymmetric centers have R configuration in the system with the complex of 9-fluorenyllithium and (-)-sparteine and those of S configuration in the systems with (+)-(2S,3S)-2,3-dimethoxy-1,4-bis(dimethylamino)butane and (+)-(S)-1-(2-pyrrolidinylmethyl)pyrrolidine as chiral ligands predominantly propagated to a one-handed helical polymer. A stable helix starts at degree of polymerization 9 in the former system and at degree of polymerization 7 in the latter two systems. One helix turn seems to consist of three or four monomeric units. The main chain of the resulting polymer in the former system possessed RPR--- absolute configuration and that in the latter systems SSS---, though both polymers are considered to be of the same helicity, P or M. These results indicate that the helicity of the polymer is not governed by the configuration of the main chain but by the chirality of the ligands.
  • Y OKAMOTO, T NAKANO, T FUKUOKA, K HATADA
    POLYMER BULLETIN 26 (3) 259 - 264 0170-0839 1991/08 [Refereed][Not invited]
     
    Cyclopropyldiphenylmethyl and cyclohexyldiphenylmethyl methacrylates were polymerized with chiral anionic initiators in toluene at low temperature. The former monomer gave an atactic polymer and the latter monomer a highly isotactic, optically active polymer of one-handed helical conformation. The optically active polymer underwent a helix-helix transition in chloroform at 60-degrees-C.
  • Y OKAMOTO, T NAKANO, E ONO, K HATADA
    CHEMISTRY LETTERS (3) 525 - 528 0366-7022 1991/03 [Refereed][Not invited]
     
    Anionic polymerization of (+)-(S)-diphenyl(1-methyl-pyrrolidin-2-yl)methyl methacrylate gave an optically active polymer of helical conformation of single screwsense. The polymer exhibited a reversible helix-helix transition in a solution of methanol containing an acid.
  • Y OKAMOTO, T NAKANO, T ASAKURA, H MOHRI, K HATADA
    JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 29 (2) 287 - 289 0887-624X 1991/02 [Refereed][Not invited]
  • Synthesis and conformational change of helical polymethacrylates
    Okamoto, Yoshio, Nakano, Tamaki, Hatada, Koichi
    Polymer Preprints 32 (1) 451 - 452 1991 [Refereed][Not invited]
  • Y OKAMOTO, H MOHRI, T NAKANO, K HATADA
    CHIRALITY 3 (4) 277 - 284 0899-0042 1991 [Refereed][Not invited]
     
    Polymerization of diphenyl-2-pyridylmethyl methacrylate was carried out with the complexes of organolithium compounds with 22 chiral ligands. Helix-sense-selectivity of the polymerization was largely affected by a slight structural difference of chiral ligands. (+)-(S)-2-(1-Pyrrolidinylmethyl)pyrrolidine was the most effective ligand in producing a one-handed helical polymer with narrow molecular weight distribution.
  • Y OKAMOTO, H MOHRI, T NAKANO, K HATADA
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 111 (15) 5952 - 5954 0002-7863 1989/07 [Refereed][Not invited]
  • Y OKAMOTO, T NAKANO, K HATADA
    POLYMER JOURNAL 21 (2) 199 - 201 0032-3896 1989 [Refereed][Not invited]
  • Haloaldehyde polymers, XXXV, Proton, fluorine, and carbon, NMR spectra, stereochemistry of bornyl, esters of fluorochlorobromoacetic acid
    Polymer Journal 21 (2) 171 - 177 0032-3896 1989 [Refereed][Not invited]
  • Hatada, Koichi, Ute, Koichi, Nakano, Tamaki, Vass, Frantisek, Vogl, Otto
    Makromolekulare Chemie 190 (9) 2217 - 2228 0025-116X 1989 [Refereed][Not invited]
  • Okamoto, Yoshio, Nakano, Tamaki
    Yuki Gosei Kagaku Kyokaishi 47 (11) 1029 - 1039 0037-9980 1989 [Refereed][Not invited]
  • T NAKANO, K UTE, Y OKAMOTO, Y MATSUURA, K HATADA
    POLYMER JOURNAL 21 (11) 935 - 939 0032-3896 1989 [Refereed][Not invited]
  • Synthesis and reversible helix-helix transition of poly[(S)-diphenyl(1-methylpyrrolidin-2-yl)methyl methacrylate]
    Okamoto, Yoshio, Nakano, Tamaki, Mohri, Haruhiko, Ono, Etsuko, Hatada, Koichi
    Polymer Preprints 30 (2) 408 - 409 1989 [Refereed][Not invited]
  • Asymmetric polymerization of methacrylates leading to a one-handed helix
    Okamoto, Yoshio, Nakano, Tamaki, Mohri, Haruhiko, Asakura, Toshikage, Hatada, Koichi
    Polymer Preprints 30 (2) 437 - 438 1989 [Refereed][Not invited]
  • Y OKAMOTO, E YASHIMA, T NAKANO, K HATADA
    CHEMISTRY LETTERS (5) 759 - 762 0366-7022 1987 [Refereed][Not invited]

Books etc

  • Asymmetric Polymerization
    Tamaki Nakano (ContributorIn Encyclopedia of Polymeric Nanomaterials)
    Elsevier 2015
  • 中野 環 
    Springer 2014 (ISBN: 9784431541288)
  • Synthesis and Properties of pi-Stacked Vinyl Polymers
    Tamaki Nakano (ContributorIn Synthesis and Properties of pi-Stacked Vinyl Polymers)
    Springer Japan 2013
  • pi-Stacked Polymers and Molecules: Theory, Synthesis, and Properties
    Tamaki Nakano (Editor)
    Springer Japan 2013
  • Comprehensive Polymer Science 2nd Ed
    Elsevier 2011
  • 新訂 ラジカル重合ハンドブック
    NTS 2010
  • 中野 環 
    [奈良先端科学技術大学院大学] 2006

MISC

  • 中野 環  化學工業  66-  (2)  92  -96  2015/02  [Not refereed][Not invited]
  • Nakano Tamaki  Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute  2014-  (0)  2014  [Not refereed][Not invited]
     
    Chiral structural regulation to polymers and small molecules was achieved using circularly polarized light as chiraliy sourse. &nbsp;First, a preferred-handed helical conformation was induced to main-chain conjugated polymers by this method. &nbsp;Second, the scope was expanded to vinyl polymers and related small molecules.
  • 中野環  ポリマーフロンティア21講演要旨集  2012-  (6)  13  -17  2013/03/08  [Not refereed][Not invited]
  • T. Nakano, Y. Okamoto  Polymer Science: A Comprehensive Reference, 10 Volume Set  6-  629  -687  2012/12/01  [Not refereed][Not invited]
     
    Synthesis and structure of conformationally and configurationally chiral polymers are overviewed. Helix is the most representative chiral conformation, and helical polymers can be divided into three types, namely, those with static helix, those with dynamic helix, and those formed by chain folding (foldamers). Single-handed helicity is realized by helix-sense-selective polymerization for polymers with static helix and by covalent or supramolecular interaction of the polymer chain with chiral groups or chiral added molecules for polymers with dynamic helix and for foldamers. Polymers having configurational chirality in the main chain or the side chain are prepared by asymmetric synthesis polymerization or enantiomer-selective polymerization. © 2012 Elsevier B.V. All rights reserved.
  • 中野環  高分子  61-  (10)  767  -768  2012/10/01  [Not refereed][Not invited]
  • 渡辺顕士, 鈴木望, 藤木道也, 中野環  高分子学会予稿集(CD-ROM)  61-  (2)  ROMBUNNO.1E07  2012/09/05  [Not refereed][Not invited]
  • 関口康行, 中野環, 菊池悠嗣, 氏家誠司, 長谷川仁子, 七分勇勝, 小西克明  高分子学会予稿集(CD-ROM)  61-  (1)  ROMBUNNO.1PG027  2012/05/15  [Not refereed][Not invited]
  • 渡辺顕士, 鈴木望, 藤木道也, 中野環  高分子学会予稿集(CD-ROM)  61-  (1)  ROMBUNNO.3F02  2012/05/15  [Not refereed][Not invited]
  • 村木峻, 渡辺顕士, LI Geng, 中野環  高分子学会予稿集(CD-ROM)  61-  (1)  ROMBUNNO.2PB012  2012/05/15  [Not refereed][Not invited]
  • 中野 環  未来材料  10-  (10)  25  -31  2010/10  [Not refereed][Not invited]
  • NAKANO Tamaki  高分子  59-  (3)  164  -168  2010/03/01  [Not refereed][Not invited]
  • 永 直文, 中野 環  特別教育・研究報告集  2007-  103  -106  2007  [Not refereed][Not invited]
  • 中野 環, 八重樫 敬之, 中川 修  高分子論文集  63-  (7)  492  -497  2006  [Not refereed][Not invited]
  • 中野 環  化学工業  56-  (3)  195  -202  2005/03  [Not refereed][Not invited]
  • 中野 環, 矢出 亨, 中川 修  接着  48-  (8)  352  -359  2004/08  [Not refereed][Not invited]
  • NAKANO Tamaki  KOBUNSHI RONBUNSHU  58-  (8)  411  -426  2001/08/25  [Not refereed][Not invited]
  • T Nakano, Y Okamoto  MACROMOLECULAR RAPID COMMUNICATIONS  21-  (10)  603  -612  2000/07  [Not refereed][Not invited]
     
    The syntheses of optically active polymers having helical conformation from bulky methacrylates are reviewed focusing on selected topics. The monomers include triphenylmethyl methacrylate and its analogues. Asymmetric anionic polymerization of the monomers gives isotactic, optically active polymers having a helical structure with excess helicity, The isotactic content and the extent of helical-sense excess depend on the monomer structure and the reaction conditions. In the case of methacrylates, completely isotactic and single-handed helical polymers can be produced by asymmetric anionic polymerization (helix-sense-selective polymerization). Asymmetric radical polymerization is also possible for this class of monomer. Some of the helical polymers show chiral recognition ability coward a wide range of racemic compounds. Polymers having main-chain configurational chirality are also discussed.
  • WH Liu, T Nakano, Y Okamoto  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY  38-  (6)  1024  -1032  2000/03  [Not refereed][Not invited]
     
    The free-radical polymerization of 2,2,2-trifluoroethyl acrylate (TFEA), 1,1,1,3,3,3-hexafluoro-2-propyl acrylate (HFiPA) and perfluoro-tert-butyl acrylate (PFtBA) was carried out under various conditions and the stereostructure of the obtained polymers was investigated. Most polymerizations of the three monomers afforded polymers rich in diad syndiotacticity (r) in bulk or in solution; the r-specificity was higher in the HFiPA and PFtBA polymerization than in the TFEA polymerization. Although the tacticity was nearly independent of reaction temperature during the polymerization of TFEA, the r-specificity increased by lowering the reaction tempera -ture during the polymerization of the other two monomers. The polymerization stereochemistry was also affected by the reaction solvents including toluene, tetrahydrofuran, and fluoroalcohols. It was noted that the stereochemistry of the polymerization of HFiPA and PFtBA also depended on the monomer concentration, and a lower monomer concentration led to a higher r-specificity. By optimizing the aforementioned reaction conditions, the poly(HFiPA) having r = 81% (polymerization in tetrahydrofuran at -98 degrees C at [M](o) = 0.2M) and the poly(PFtBA) having r = 77% (polymerization in toluene at -78 degrees C at [M](o) = 0.2M) were obtained. (C) 2000 John Wiley & Sons, Inc.
  • K Yamada, T Nakano, Y Okamoto  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY  38-  (1)  220  -228  2000/01  [Not refereed][Not invited]
     
    Free-radical copolymerizations of vinyl acetate (VAc = M-1) and other vinyl esters (= M-2) including vinyl pivalate (VPi), vinyl 2,2-bis(trifluoromethyl)propionate (VF6Pi), and vinyl benzoate (VBz) with fluoroalcohols and tetrahydrofuran (THF) as the solvents were investigated. The fluoroalcohols affected not only the stereochemistry but also the polymerization rate. The polymerization rate was higher in the fluoroalcohols than in THF. The accelerating effect of the fluoroalcohols on the polymerization was probably due to the interaction of the solvents with the ester side groups of the monomers and growing radical species. The difference in the monomer reactivity ratios (r(1), r(2)) in THF and 2,2,2-trifluoroethanol was relatively small for all reaction conditions and for the monomers tested in this work, whereas r(1) increased in the VAc-VF6Pi copolymerization and r(2) decreased in the VAc-VPi copolymerization when perfluorotert-butyl alcohol was used as the solvent. These results were ascribed to steric and monomer-activating effects due to the hydrogen bonding between the monomers and solvents. (C) 2000 John Wiley & Sons, Inc.
  • K Yamada, T Nakano, Y Okamoto  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY  37-  (14)  2677  -2683  1999/07  [Not refereed][Not invited]
     
    Free-radical polymerization of vinyl esters including vinyl propionate (VPr), vinyl isobutylate (ViBu), vinyl 2,2-dimethylbutylate (VDMB), vinyl 2,2-dimethylvalerate (VDMV), vinyl 2,2-bis(trifluoromethyl)propionate (VF6Pi), and vinyl benzoate (VBz) was carried out using fluoroalcohols as solvents, and the tacticity of the obtained polymers was determined by NMR analysis of the produced poly(vinyl alcohol) (PVA). The polymerization of VPr, ViBu, VDMB, and VDMV, which are bulkier than VAc, in fluoroalcohols afforded polymers rich in heterotacticity (up to mr = 61%) similar to that of vinyl pivalate (VPi) whereas VAc is known to give a syndiotactic polymer under the reaction conditions used here. The polymerization of VF6Pi, which is the bulkiest among the monomers used in this study, gave a polymer rich in syndiotacticity in bulk and in fluoroalcohols regardless of the structure of the solvents. On the other hand, the polymerization of VBz in fluoroalcohols gave olymers with a higher isotacticity (up to mm = 33%) than bulk polymerization. Thus the monomer structure strongly affected the stereochemistry of the free-radical polymerization of vinyl esters in fluoroalcohols. (C) 1999 John Wiley & Sons, Inc.
  • J Wu, T Nakano, Y Okamoto  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY  37-  (14)  2645  -2648  1999/07  [Not refereed][Not invited]
     
    Almost optically pure (+)- and (-)-2-fluorophenyl-4-fluorophenyl-2-pyridylmethyl methacrylate (2F4F2PyMA) monomers were obtained by HPLC resolution of the racemic monomer and polymerized with the use of anionic and free-radical initiators. Helix-sense selectivity during the polymerization seemed to be governed mainly by the chirality of the monomer itself, and the polymers obtained by using the complex of N,N'-diphenylethylenediamine monolithium amide with(S)-(+)-1-(2-pyrrolidinylmethyl)-pyrrolidine (PMP) in toluene at -78 degrees C appeared to possess single-handed helical conformation (+)-poly[(-)-2F4F2PyMA], [alpha](365) + 1510 degrees; (-)-poly[(+)-2F4F2PyMA], [alpha](365) - 1610 degrees]. The single-handed helical (+)-poly[(-)-2F4F2PyMA] and (-)-poly[(+)-2F4F2PyM] obtained with the PMP complex exhibited better chiral recognition ability toward trans-stilbene oxide compared with the single-handed helical poly(rac-2F4F2PyMA) prepared previously. (C) 1999 John Wiley & Sons, Inc.
  • J Wu, T Nakano, Y Okamoto  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY  36-  (12)  2013  -2019  1998/09  [Not refereed][Not invited]
     
    A novel racemic methacrylate, (2-fluorophenyl)( 4-fluorophenyl)( 2-pyridyl)-methyl methacrylate(1) (2F4F2PyMA), was synthesized and polymerized with chiral complexes of N,N'-diphenylethylenediamine monolithium amide (DPEDA-Li) with (-)-sparteine (Sp), (2S, 3S)-(+)-2,3-dimethoxy-1,4-bis(dimethylamino)bu (DDB), and (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine (PMP) in toluene at -78 degrees C. The monomer showed higher resistance against methanolysis compared with triphenylmethyl methacrylate (TrMA) and several other analogues. In the asymmetric anionic polymerization of 2F4F2PyMA, PMP was found to be a more effective chiral ligand than DDB and Sp and gave quantitatively an optically active polymer with nearly perfect isotacticity. Enantiomer selection was observed in the polymerization of racemic 2F4F2PyMA with the chiral lithium complexes. Chiral recognition ability of the optically active poly( 2F4F2PyMA) was examined by an enantioselective adsorption experiment. (C) 1998 John Wiley & Sons, Inc.
  • NAKANO Tamaki  高分子学会予稿集  46-  (1)  64  -66  1997/05/10  [Not refereed][Not invited]
  • NAKANO Tamaki  高分子  46-  (2)  1997/02  [Not refereed][Not invited]
  • 中野 環  日産科学振興財団研究報告書  (20)  139  -142  1997  [Not refereed][Not invited]
  • Dotsevi Y. Sogah, S. Zheng, T. Nakano  American Chemical Society, Polymer Preprints, Division of Polymer Chemistry  37-  442  -443  1996/08/01  [Not refereed][Not invited]
  • T Nakano, A Matsuda, M Mori, Y Okamoto  POLYMER JOURNAL  28-  (4)  330  -336  1996  [Not refereed][Not invited]
     
    Asymmetric anionic polymerization of 1-phenyldibenzosuberyl methacrylate [5-phenyldibenzosuberan-5-yl methacrylate, 5-phenyl-10,11-dihydrodibenzo[a,d]cyclohepten-5-yl methacrylate] (1), and 1-(2-pyridyl)dibenzosuberyl methacrylate] [5-(2-pyridyl)dibenzosuberan-5-yl methacrylate, 5-(2-pyridyl)-10,11-dihydrodibenzo[a,d]cyclohepten-5-yl methacrylate] (2) was carried out using complexes of N,N'-diphenylethylenediamine monolithium amide with (-)-sparteine (Sp), (+)-1-(2-pyrrolidinylmethyl)pyrrolidine (PMP), and (+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane (DDB) in toluene at -78 degrees C. The polymers of 1 quantitatively obtained with the three complexes were highly isotactic and showed high optical activity ([alpha](365) + 1670-1780 degrees, [alpha](D) + 420-480 degrees) and intense circular dichroism absorptions based on one-handed helical conformation of main chain. In contrast, 2 gave one-handed helical polymers only by the polymerization with the Sp and PMP complexes. The polymerization of 2 with the DDB complex was sluggish. Monomers 1 and 2 showed higher resistance against methanolysis compared with triphenylmethyl methacrylate and diphenyl-2-pyridylmethyl methacrylate, respectively. The obtained optically active polymers resolved several racemic compounds.
  • 岡本 佳男, 中野 環  旭硝子財団助成研究成果報告  (1993)  17  -24  1993/11  [Not refereed][Not invited]
  • Nakano Tamaki, Okamoto Yoshio  Kobunshi  42-  (11)  923  -923  1993  [Not refereed][Not invited]
  • 中野 環, 岡本 佳男  季刊化学総説  (18)  129  -136  1993  [Not refereed][Not invited]

Industrial Property Rights

Awards & Honors

  • 2009 高分子学会賞
  • 1996 高分子学会ポリマージャーナル論文賞
  • 1996 1996 SPSJ Award for the Outstanding Paper in Polymer Journal

Research Grants & Projects

  • 文部科学省:科学研究費補助金(基盤研究(B))
    Date (from‐to) : 2010 -2012 
    Author : 中野 環
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    Date (from‐to) : 2011 -2011 
    Author : 中野 環
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    Date (from‐to) : 2009 -2010 
    Author : 中野 環, 坂本 猛
     
    本研究は、従来、触媒的合成反応や超分子的相互作用を用いて制御されてきた高分子の一方向巻きのらせん構造を、光(円偏光)のみを用いて制御することを目的とした。代表者らの従来の研究成果から、光照射によるビフェニル基のねじれ-平面転移が高分子鎖の構造変化の誘起に有効であることが判明していたため、側鎖にビフェニル残基を有し、光で構造を変えられると考えられるポリ[2,7-ビス(4-t-ブチルフェニル)ジベンゾフルベン](poly-1)を合成した。合成は、光学活性アニオン開始剤およびアキラルなアニオン開始剤を用いて行った。光学活性なメントキシカリウムを用いた重合では一方向に偏ったらせん構造を有すると考えられる光学活性ポリマーが得られた。この光学活性ポリマーに非偏光を照射したところ、ポリマーの円偏光二色性スペクトルには顕著な変化が観測され、らせん構造が一部ラセミ化あるいはランダムコイル化したことが示唆された。これにより、poly-1が光で構造を変えるポリマーであることが確認されたため、次に、アキラルなpoly-1に溶液中で円偏光を照射した。しかし、光照射後のポリマーは優位なキラル物性を示さなかった。これは、この物質の溶液中でのKuhn非対称因子が非常に小さいためと考えられた。そこで、次にアキラルなpoly-1を薄膜状にして円偏光を照射したところ、薄膜はキラル物性を示し、光により一方向に偏った...
  • 文部科学省:科学研究費補助金(萌芽研究)
    Date (from‐to) : 2006 -2007 
    Author : 中野 環
     
    最終目的生成物である高分子のモノマー単位のモデルとしての9,9'-ビフルオレニリデンのキラリティーと光異性化について、ポリマーについての検討に先立って、試験的な実験を行った。この目的で、9,9'-ビフルオレニリデンと(+)-ビナフトールを混合してメタノール溶液として、あるいは9,9'-ビフルオレニリデンと(-)-メントールを混合してトルエン溶液として、あるいは9,9'-ビフルオレニリデンと(-)-α-(2,4,5,7-テトラニトロ-9-フルオレニリデンアミノキシ)プオピオン酸を混合してメタノール溶液として、あるいは9,9'-ビフルオレニリデンと(-)-α-(2,4,5,7-テトラニトロ-9-フルオレニリデンアミノキシ)プオピオン酸を混合してメタノール溶液として、窒素雰囲気下で500Wのハロゲン灯を照射した。その結果、前年度(+)-ピネンをキラル源として用いた場合に観測された円偏光二色性(CD)スペクトルはほとんど見られず、(+)-ピネンに比べて、他の3種のキラル化合物は9,9'-ビフルオレニリデンの光異性化においてキラル誘起のためには有効でないことが明らかになった。以上に加えて、9,9'-ビフルオレニリデンと(-)-α-(2,4,5,7-テトラニトロ-9-フルオレニリデンアミノキシ)プオピオン酸の錯体形成による、9,9'-ビフルオレニリデンの光学分割も試みた。両者を混合してメ...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
    Date (from‐to) : 2004 -2005 
    Author : Tamaki NAKANO
     
    We found that free-radical polymerization under appropriate conditions can give polydibenzofulvene having a π-stacked conformation as well as anionic polymerization. The free-radical polymerization product contained a small amount of defective conformation incorporated in the chain. Such a partial conformational defect was revealed to contribute to increase solubility of the polymer. In addition, as a new bulky dibenzofulvene derivative, 2,7-di-t-butyldibenzofulvene, was synthesized and polymerized in order to examine the effect of the side chain on polymerizability of the monomer and prope...
  • 文部科学省:科学研究費補助金(特定領域研究(B), 特定領域研究)
    Date (from‐to) : 2001 -2003 
    Author : 幅上 茂樹, 山本 智代, 中野 環, 覚知 豊次, 波多野 豊平
     
    一方向巻きのらせん構造を有するポリ(メタクリル酸エステル)誘導体をテンプレートとして用い,分子インプリント法を応用することにより,キラルならせん状空孔の形成,さらには,多様なキラル分子に対する不斉認識能を有する新規高分子ゲルの構築について検討した.これまでの研究より,共重合モノマーとしてα-(ベンジルオキシメチル)アクリル酸誘導体を用いることにより,通常分子インプリント法で用いられるメタクリル酸などに比べ,.より効果的にキラルゲルを構築できることを明らかにしている.これはテンプレートと2点で相互作用することが可能なこの2官能性モノマーの特徴的な構造に基づくものであると考えられる.そこで,実用性の観点から,市販の種々の2官能性モノマーを共重合モノマーとして用いた新規キラルゲル構築法について検討した.2官能性モノマーとしてマレイン酸誘導体などを用い,これまでに確立した方法を応用し,キラルゲルの構築を行った.その結果,いずれの場合にもほぼ定量的にゲルを合成することができた.得られたゲルの不斉認識能をtrans-スチルベンオキシド,トレガー塩基などのラセミ体を用いて不斉吸着実験による評価を行った.その結果,いずれのゲルも不斉識別能を示した.たとえばマレイン酸から得られたゲルは,特にtrans-スチルベンオキシドに対して高い不斉識別能を示し,市販の2官能性モノマーを用いた本手法が,有効...
  • 文部科学省:科学研究費補助金(奨励研究(A))
    Date (from‐to) : 1999 -2000 
    Author : 中野 環
     
    重合系の成長ラジカルと相互作用し得る光学活性金属ラジカル種を設計、合成し、ラジカル重合系に添加して生成ポリマーの立体構造に与える影響について調べた。金属ラジカル種としては光学活性な(R,R)-N,N-ビス(3,5-tert-ブチルサリチリデン)-1,2-シクロヘキサンジアミナトコバルト(II)および銅(II)を用い、トルエン-ピリジン(95/5)中あるいはテトラヒドロフラン-THF中でα,α'-アゾビスイソブチロニトリルを開始剤とするN-シクロへキシルマレイミド(cHMI)のラジカル重合について検討した。コバルト錯体存在化で生成したポリマーには主鎖の不斉炭素の絶対配置の偏りに基づくと考えられる旋光性および円偏光二色性スペクトルが観測された。光学活性コバルト錯体の影響でラジカル重合中に主鎖に不斉誘導がおきたことが示唆された。この重合反応は、コバルト錯体存在下ではラジカル禁止剤であるTEMPOを加えても進行し、また、モノマーとコバルト錯体の溶液を室温に放置するだけでも効率良く進行した。この事から、重合機構にはフリーラジカル重合種は含まれておらず、また、モノマーとコバルト錯体の相互作用により活性種が発生することが示唆された。銅錯体はコバルト錯体ほどの不斉誘導効果は示さなかった。
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 1996 -1998 
    Author : Yoshio OKAMOTO, 幅上 茂樹, 市田 昭人, 中野 環, 八島 栄次
     
    Phenylcarbamate derivatives of polysaccharides such as cellulose and amylose show high chiral recognition abilities as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) and can resolve a broad range of enantiomers. In this study, the chiral recognition mechanism of the phenylcarbamate derivatives was mainly investigated.1. We found that amylose tris (3, 5-dimethylphenylcarbamate) (ADMPC) with low degree of polymerization is soluble in chloroform. This enabled us to study the chiral recognition mechanism of ADMPC by NMR spectroscopy. ADMPC exhibited chiral dis...
  • 文部科学省:科学研究費補助金(萌芽的研究)
    Date (from‐to) : 1996 -1997 
    Author : 中野 環
     
    ビニルモノマーのラジカル重合の立体規制を目的として、まず、粘土(モンモリロナイト、サポナイト)と2-および4-ビニルピリジンの塩酸塩の錯体を形成させ、粘土の層間での重合を試みた。モンモリロナイト、サポナイトいずれを用いた場合にもモノマーの塩酸塩は効率よく粘土中に取り込まれた。錯体に紫外線照射して重合を試みたところ、2-5量体程度のオリゴマーが主に生成し高分子量の生成物は得られなかった。次に粘土に換えて、臭化マグネシウム、臭化リチウム、光学活性なメントキシマグネシウムブロミド、メントキシリチウムの存在下での2-および4-ビニルピリジンおよびメタクリル酸2-ピリジルメチルの重合について検討した。2-ビニルピリジンの重合の立体化学には金属塩の影響はほとんど見られなかったが、4-ビニルピリジンの場合には金属塩の存在により生成ポリマーのイソタクチック含量が増加する傾向が明確に見られた。これはモノマーおよび成長種のピリジル基に金属塩が配位した結果、モノマーおよび成長種が見掛け上嵩高くなったためと考えられる。ただし、光学活性錯体を用いても有意な不斉誘起は確認されなかった。メタクリル酸2-ピリジルメチルの重合でもリチウム塩、マグネシウム塩との錯体形成による重合の立体化学への影響が見られ、金属塩の存在によりイソタクチック選択性が向上し、シンジオタクチック選択性が低下する現象が観測された。
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(一般研究(B), 基盤研究(B))
    Date (from‐to) : 1995 -1996 
    Author : Yoshio OKAMOTO, 幅上 茂樹, 中野 環, 八島 栄次
     
    1. The presence of cobaltus complexes including (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminatocobalt (II) (1) was found to affect stereochemistry of free-radical polymerization of methyl, benzyl, isopropyl, and t-butyl methacrylates. In the polymerization of t-butyl ester, a decrease of 12% in rrrr pentad content was observed based on 1. Tacticity of polymers obtained from the other monomers such as vinyl acetate, stirene, and acrylates were also affected by the added radical complex where the magnitude of the effect varied depending on the combination of monomer and...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(試験研究(B))
    Date (from‐to) : 1993 -1995 
    Author : Yoshio OKAMOTO, 中野 環, 市田 昭人, 猪爪 信夫, 八島 栄次, 幅上 茂樹, 中野 環
     
    1. Phenylcarbamate derivatives of cellulose and amylose having chloro or fluoro and methyl groups on the phenyl moieties were synthesized, and their chiral recognition abilities were evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). The cellulose derivatives with halogen and methyl groups at the meta and para positions showed higher resolving power than the ortho- and meta-disubstituted derivative. On the other hand, the ortho-substituted derivative of amylose showed slightly lower chiral recognition than those of the meta- and para-disubstitute...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(一般研究(A))
    Date (from‐to) : 1992 -1994 
    Author : Yoshio OKAMOTO, 中野 環, 八島 栄次, 幅上 茂樹
     
    1. Optically active, helical polymers were successfully synthesized from novel methacrylates, acrylates, and acrylamides. Diphenyl-3-pyridylmethyl methacrylate, phenyl-bis (2-pyridyl) methyl methacrylate, 1-phenyldibenzosuberyl methacrylate, and 1- (2-pyridyl) dibenzosuberyl methacrylate gave almost perfectly isotactic, one-handed helical polymers through anionic polymerization using the complex of N,N'-diphenylethylenediamine monolithium amide with (+) -1- (2-pyrrolidinylmethyl) pyrrolidine. Helix-sense-selective polymerization of the latter two monomers was realized also through radical m...
  • 文部科学省:科学研究費補助金(重点領域研究)
    Date (from‐to) : 1993 -1993 
    Author : 岡本 佳男, 中野 環, 八島 栄次
     
    本研究では、高速液体クロマトグラフィー(HPLC)用のキラル充填剤として、すぐれた不斉識別能を有する新規な多糖誘導体の合成を行い、その不斉識別能を評価するとともに、NMRによる不斉識別機構の解明を行った。1.フェニル基上の様々な位置に、メチル基とクロロ基を同時に有する多糖の二置換フェニルカルバメート誘導体を合成した。セルロース誘導体では、メタおよびパラ位に置換基を有する誘導体が極めて高い分割能を示したのに対し、アミロース誘導体では、オルト位に置換基を有する誘導体が最も高い光学分割能を示した。2.側鎖の2、3位および6位を位置特異的にフェニルカルバメートおよびベンゾエート基で修飾した多糖誘導体を合成し、その光学分割能を調べたところ、セルロース誘導体では、側鎖の置換基の位置と種類により光学分割能は変化した。一方、アミロース誘導体では、側鎖を位置特異的に変換した誘導体より、ランダムに変換した誘導体が高い不斉識別能を示し、実用性の高いカラムとなることが明かになった。3.多糖フェニルカルバメート誘導体を少量のジイソシアナートを用いてシリカゲルに位置特異的に化学結合したところ、優れた耐久性と多くのラセミ体に対して、従来の吸着型充填剤と変わらない高い光学分割能を有することが明らかになった。4.セルローストリス(4-トリメチルシリルフェニルカルバメート)(CTMSC)は、高い不斉識別能を示し...
  • キラル高分子、光電子機能性高分子
    Date (from‐to) : 1989
  • Chiral polymers, Polymers with photoelectronic properties
    Date (from‐to) : 1989

Educational Activities

Teaching Experience

  • 分子化学(集合機能化学)
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 総合化学院
  • Molecular Chemistry (Macromolecular Science)
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 総合化学院
    キーワード : 高分子,立体化学,立体特異性,コンホメーション,光学活性,キラリティー,らせん構造
  • Environment and People
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 触媒、化学物質、環境とエネルギー、持続的な社会発展
  • Catalytic Chemistry
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 触媒,触媒化学,表面科学,高分子化学,理論化学

Campus Position History

  • 2018年4月1日 
    2020年3月31日 
    触媒科学研究所附属触媒連携研究センター長

Position History

  • 2018年4月1日 
    2020年3月31日 
    触媒科学研究所附属触媒連携研究センター長


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