The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Yoshiki Chujo - One of the best experts on this subject based on the ideXlab platform.
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p stereogenic Optically Active Polymer and the complexation behavior
Macromolecular Chemistry and Physics, 2011Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:The synthetic details of the P-stereogenic Optically Active Polymer and the complexation behavior with palladium and platinum complexes are reported. The Polymer consists of P-stereogenic bisphosphine units and the conjugated phenylene-ethynylene units alternately. The P-stereogenic bisphosphine moieties can coordinate to transition metals such as palladium and platinum, leading to a change in the conformation.
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P‐Stereogenic Optically Active Polymer and the Complexation Behavior
Macromolecular Chemistry and Physics, 2011Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:The synthetic details of the P-stereogenic Optically Active Polymer and the complexation behavior with palladium and platinum complexes are reported. The Polymer consists of P-stereogenic bisphosphine units and the conjugated phenylene-ethynylene units alternately. The P-stereogenic bisphosphine moieties can coordinate to transition metals such as palladium and platinum, leading to a change in the conformation.
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synthesis of Optically Active Polymer with p stereogenic phosphine units
Macromolecular Rapid Communications, 2010Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:: Optically Active Polymer containing P-stereogenic bisphosphine as a repeating unit in the main was successfully synthesized. A coordinated borane on the phosphorus atom could be completely removed by an organic base under mild condition, and the successive reaction with Pd afforded the corresponding Polymer complex. The chirality of P-stereogenic centers was transferred to the m-phenylene-ethynylene linkers by complexation because of the prohibition of the rotary motion of the bisphosphine-Pd unit.
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Synthesis of Optically Active Polymer with P‐Stereogenic Phosphine Units
Macromolecular Rapid Communications, 2010Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:: Optically Active Polymer containing P-stereogenic bisphosphine as a repeating unit in the main was successfully synthesized. A coordinated borane on the phosphorus atom could be completely removed by an organic base under mild condition, and the successive reaction with Pd afforded the corresponding Polymer complex. The chirality of P-stereogenic centers was transferred to the m-phenylene-ethynylene linkers by complexation because of the prohibition of the rotary motion of the bisphosphine-Pd unit.
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Synthesis of the Optically Active Polymer Consisting of Chiral Phosphorus Atoms and p-Phenylene-ethynylene Units
Polymer Bulletin, 2007Co-Authors: Yasuhiro Morisaki, Yuko Ouchi, Kazuhiko Tsurui, Yoshiki ChujoAbstract:We successfully synthesized Optically Active Polymer 4 by using chiral bisphosphine, ( S , S )-1,2-bis(boranato( t -butyl)methylphosphino)ethane ( S , S )- 1 , as a key building block. The structure of the Polymer was characterized by ^1H, ^13C, and ^31P NMR spectra. According to the CD spectra, the p -phenylene-ethynylene unit in the Polymer main chain exhibited Cotton signals around the area of π-π^* transition band.
Yoshio Okamoto - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric Polymerization of 1-(3-Pyridyl)dibenzosuberyl Methacrylate and Chiral Recognition by the Obtained Optically Active Polymer Having Single-Handed Helical Conformation
Polymer Journal, 1998Co-Authors: Tamaki Nakano, Yoichi Satoh, Yoshio OkamotoAbstract: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°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°C and with α,α′-azobisisobutyronitrile at 60°C gave nearly perfectly isotactic Polymers. The Optically Active Polymer exhibited chiral recognition ability toward trans -stilbene oxide and Tröger’s base as revealed by chiral adsorption experiments.
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asymmetric Polymerization of diphenyl 3 pyridylmethyl methacrylate leading to Optically Active Polymer with helical conformation and chiral recognition ability of the Polymer
Polymer Journal, 1997Co-Authors: Tamaki Nakano, Kyoichi Taniguchi, Yoshio OkamotoAbstract:Asymmetric Polymerization of Diphenyl-3-pyridylmethyl Methacrylate Leading to Optically Active Polymer with Helical Conformation and Chiral Recognition Ability of the Polymer
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Asymmetric Polymerization of Diphenyl-3-pyridylmethyl Methacrylate Leading to Optically Active Polymer with Helical Conformation and Chiral Recognition Ability of the Polymer
Polymer Journal, 1997Co-Authors: Tamaki Nakano, Kyoichi Taniguchi, Yoshio OkamotoAbstract: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°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°C also gave an isotactic Polymer ( mm ∼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).
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Helical Polymers: Synthesis, Conformation, and Function
New Macromolecular Architecture and Functions, 1996Co-Authors: Yoshio Okamoto, Tamaki Nakano, Shigeki HabaueAbstract:Asymmetric Polymerization of acrylic monomers and an isocyanate derivative leading to a helical conformation is described. 1-Phenyldibenzosuberyl methacrylate, triphenylmethyl acrylate, and N,N-diphenylacrylamide were Polymerized using the complexes of diphenylethylenediamine monolithium amide with (-)-sparteine, (S,S)-(+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane, and (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine. The methacrylate gave a purely one-handed helical, Optically Active Polymer ([α]365 +1670° ~ +1780°) having a perfect isotactic structure; the Polymer exhibited chiral recognition ability to some racemic compounds. This monomer gave Optically Active Polymers also by radical mechanism. The acrylate also gave an Optically Active, helical Polymer ([α]365 +102°) having a dyad isotacticity of 70% using the pyrrolidine complex. The poly(methyl acrylate) derived from the polyacrylate showed a specific rotation which appears to be based on configurational chirality of the main chain. The acrylamide gave an Optically Active Polymer ([α]365-429°) which may have a helical structure by asymmetric anionic Polymerization; the Polymer had a dyad isotacticity of 86%. m-Methylphenyl isocyanate was Polymerized using Optically Active lithium alkoxides and amides to produce a Polymer having a chiral group at the α-end. A prevailing one-handed helical structure was induced for the main chain due to the chiral end group.
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Asymmetric Anionic Polymerization of 1-Phenyldibenzosuberyl Acrylate Affording Optically Active Polymer with Helical Conformation.
Polymer Journal, 1995Co-Authors: Toshimitsu Tanaka, Shigeki Habaue, Yoshio OkamotoAbstract:Asymmetric Anionic Polymerization of 1-Phenyldibenzosuberyl Acrylate Affording Optically Active Polymer with Helical Conformation
Yasuhiro Morisaki - One of the best experts on this subject based on the ideXlab platform.
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p stereogenic Optically Active Polymer and the complexation behavior
Macromolecular Chemistry and Physics, 2011Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:The synthetic details of the P-stereogenic Optically Active Polymer and the complexation behavior with palladium and platinum complexes are reported. The Polymer consists of P-stereogenic bisphosphine units and the conjugated phenylene-ethynylene units alternately. The P-stereogenic bisphosphine moieties can coordinate to transition metals such as palladium and platinum, leading to a change in the conformation.
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P‐Stereogenic Optically Active Polymer and the Complexation Behavior
Macromolecular Chemistry and Physics, 2011Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:The synthetic details of the P-stereogenic Optically Active Polymer and the complexation behavior with palladium and platinum complexes are reported. The Polymer consists of P-stereogenic bisphosphine units and the conjugated phenylene-ethynylene units alternately. The P-stereogenic bisphosphine moieties can coordinate to transition metals such as palladium and platinum, leading to a change in the conformation.
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synthesis of Optically Active Polymer with p stereogenic phosphine units
Macromolecular Rapid Communications, 2010Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:: Optically Active Polymer containing P-stereogenic bisphosphine as a repeating unit in the main was successfully synthesized. A coordinated borane on the phosphorus atom could be completely removed by an organic base under mild condition, and the successive reaction with Pd afforded the corresponding Polymer complex. The chirality of P-stereogenic centers was transferred to the m-phenylene-ethynylene linkers by complexation because of the prohibition of the rotary motion of the bisphosphine-Pd unit.
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Synthesis of Optically Active Polymer with P‐Stereogenic Phosphine Units
Macromolecular Rapid Communications, 2010Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:: Optically Active Polymer containing P-stereogenic bisphosphine as a repeating unit in the main was successfully synthesized. A coordinated borane on the phosphorus atom could be completely removed by an organic base under mild condition, and the successive reaction with Pd afforded the corresponding Polymer complex. The chirality of P-stereogenic centers was transferred to the m-phenylene-ethynylene linkers by complexation because of the prohibition of the rotary motion of the bisphosphine-Pd unit.
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Synthesis of the Optically Active Polymer Consisting of Chiral Phosphorus Atoms and p-Phenylene-ethynylene Units
Polymer Bulletin, 2007Co-Authors: Yasuhiro Morisaki, Yuko Ouchi, Kazuhiko Tsurui, Yoshiki ChujoAbstract:We successfully synthesized Optically Active Polymer 4 by using chiral bisphosphine, ( S , S )-1,2-bis(boranato( t -butyl)methylphosphino)ethane ( S , S )- 1 , as a key building block. The structure of the Polymer was characterized by ^1H, ^13C, and ^31P NMR spectra. According to the CD spectra, the p -phenylene-ethynylene unit in the Polymer main chain exhibited Cotton signals around the area of π-π^* transition band.
Jianping Deng - One of the best experts on this subject based on the ideXlab platform.
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fabrication of Optically Active microparticles constructed by helical Polymer quinine and their application to asymmetric michael addition
Polymer, 2015Co-Authors: Haiyang Zhang, Wantai Yang, Jianping DengAbstract:Abstract This article reports a novel category of Optically Active Polymer microparticles combining helical substituted polyacetylene and quinine moieties. The microparticles were prepared through click reaction in aqueous system with the aid of stabilizer. The Polymer chains constituting the microparticles adopted helical conformations of predominantly one-handed screw sense, according to circular dichroism and UV–vis spectroscopy measurements. The quinine pendants were grafted on the helical Polymer chains and afforded the microparticles with catalytic ability for heterogeneous asymmetric Michael addition, in which a high product yield up to 86% and satisfactory enantioselectivity (83% ee) were obtained. An intriguing synergistic effect occurred in the asymmetric catalysis between the helical macromolecular frameworks and pendent quinine moieties. The reusability of the microparticles was further demonstrated. The present study not only provides a new strategy for manufacturing helical Polymer-immobilized chiral catalysts, but also opens up opportunities for developing novel macromolecular catalysts and even advanced functional chiral materials.
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helix sense selective precipitation Polymerization of achiral monomer for preparing Optically Active helical Polymer particles
Macromolecules, 2015Co-Authors: Huajun Huang, Yunbin Yuan, Jianping DengAbstract:Optically Active Polymer particles constitute a unique type of Polymer particle. However, nearly all the particles of this kind so far reported in the literature were prepared from chiral monomers. On the other hand, helix-sense-selective Polymerization (HSSP) techniques were majorly applied in solution Polymerization systems for preparing helical Polymers adopting predominant one-handed helicity. In the present study, we report the first HSSP in precipitation Polymerization systems, by which Optically Active helical Polymer particles were constructed from an achiral monomer. Achiral acetylenic monomer with bulky adamantyl group smoothly underwent helix-sense-selective precipitation Polymerization (HSSPP) with (nbd)Rh+B–(C6H5)4 as catalyst in the presence of Boc-l- or Boc-d-alanine as chiral additive. The HSSPPs provided Optically Active Polymer particles consisting of helical Polymer forming predominantly one-handed screw sense. SEM images show that the resulting Polymer particles were obtained in high y...
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helix sense selective Polymerization of achiral substituted acetylene in chiral micelles for preparing Optically Active Polymer nanoparticles effects of chiral emulsifiers
Polymer, 2014Co-Authors: Yan Li, Jianping Deng, Wantai YangAbstract:Abstract This paper reports helix-sense-selective Polymerizations (HSSPs) of achiral acetylene monomer performed in chiral micelles, by which Optically Active helical Polymer emulsions were directly obtained. The chiral micelles were constructed by chiral emulsifiers, in which achiral acetylene underwent HSSPs in the presence of catalyst [(nbd)RhCl] 2 . The chiral emulsifiers possessed different alkyl chain lengths and different amino acid groups, and their effects on HSSPs were investigated in detail. The obtained Polymer emulsions were characterized by TEM, circular dichroism and UV–vis absorption spectroscopy techniques. It is demonstrated that the Polymer chains constructing the emulsions adopted helical structures of predominantly one-handed screw sense, from which the emulsions exhibited remarkable optical activity.
Kentaro Suzuki - One of the best experts on this subject based on the ideXlab platform.
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p stereogenic Optically Active Polymer and the complexation behavior
Macromolecular Chemistry and Physics, 2011Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:The synthetic details of the P-stereogenic Optically Active Polymer and the complexation behavior with palladium and platinum complexes are reported. The Polymer consists of P-stereogenic bisphosphine units and the conjugated phenylene-ethynylene units alternately. The P-stereogenic bisphosphine moieties can coordinate to transition metals such as palladium and platinum, leading to a change in the conformation.
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P‐Stereogenic Optically Active Polymer and the Complexation Behavior
Macromolecular Chemistry and Physics, 2011Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:The synthetic details of the P-stereogenic Optically Active Polymer and the complexation behavior with palladium and platinum complexes are reported. The Polymer consists of P-stereogenic bisphosphine units and the conjugated phenylene-ethynylene units alternately. The P-stereogenic bisphosphine moieties can coordinate to transition metals such as palladium and platinum, leading to a change in the conformation.
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synthesis of Optically Active Polymer with p stereogenic phosphine units
Macromolecular Rapid Communications, 2010Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:: Optically Active Polymer containing P-stereogenic bisphosphine as a repeating unit in the main was successfully synthesized. A coordinated borane on the phosphorus atom could be completely removed by an organic base under mild condition, and the successive reaction with Pd afforded the corresponding Polymer complex. The chirality of P-stereogenic centers was transferred to the m-phenylene-ethynylene linkers by complexation because of the prohibition of the rotary motion of the bisphosphine-Pd unit.
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Synthesis of Optically Active Polymer with P‐Stereogenic Phosphine Units
Macromolecular Rapid Communications, 2010Co-Authors: Yasuhiro Morisaki, Kentaro Suzuki, Hiroaki Imoto, Yoshiki ChujoAbstract:: Optically Active Polymer containing P-stereogenic bisphosphine as a repeating unit in the main was successfully synthesized. A coordinated borane on the phosphorus atom could be completely removed by an organic base under mild condition, and the successive reaction with Pd afforded the corresponding Polymer complex. The chirality of P-stereogenic centers was transferred to the m-phenylene-ethynylene linkers by complexation because of the prohibition of the rotary motion of the bisphosphine-Pd unit.