The Experts below are selected from a list of 278535 Experts worldwide ranked by ideXlab platform
Mitsuo Sawamoto - One of the best experts on this subject based on the ideXlab platform.
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Sequence-Controlled polymers via reversible-deactivation radical polymerization
Polymer Journal, 2018Co-Authors: Makoto Ouchi, Mitsuo SawamotoAbstract:The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to Control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘Sequence Control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined Sequence like peptides in nature. Herein, some methodologies to realize Sequence Control based on RDRP are reviewed. The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only in Controlling the molecular weight and terminal structures but also in the precise synthesis of copolymers. An additional design for Controlled propagation via RDRP could lead to Control of the order of repeating units, that is, the ‘Sequence Control’, which has been recognized as the ultimate Control of precision polymerizations. In this review article, some concepts and methodologies are summarized for synthesizing Sequence-Controlled polymers based on RDRP.
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Sequence-Controlled polymers via reversible-deactivation radical polymerization
Polymer Journal, 2017Co-Authors: Makoto Ouchi, Mitsuo SawamotoAbstract:The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to Control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘Sequence Control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined Sequence like peptides in nature. Herein, some methodologies to realize Sequence Control based on RDRP are reviewed.
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a strategy for Sequence Control in vinyl polymers via iterative Controlled radical cyclization
Nature Communications, 2016Co-Authors: Yusuke Hibi, Makoto Ouchi, Mitsuo SawamotoAbstract:There is a growing interest in Sequence-Controlled polymers toward advanced functional materials. However, Control of side-chain order for vinyl polymers has been lacking feasibility in the field of polymer synthesis because of the inherent feature of chain-growth propagation. Here we show a general and versatile strategy to Control Sequence in vinyl polymers through iterative radical cyclization with orthogonally cleavable and renewable bonds. The proposed methodology employs a repetitive and iterative intramolecular cyclization via a radical intermediate in a one-time template with a radical-generating site at one end and an alkene end at the other, each of which is connected to a linker via independently cleavable and renewable bonds. The unique design specifically allowed Control of radical addition reaction although inherent chain-growth intermediate (radical species) was used, as well as the iterative cycle and functionalization for resultant side chains, to lead to Sequence-Controlled vinyl polymers (or oligomers).
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design of ab divinyl template monomers toward alternating Sequence Control in metal catalyzed living radical polymerization
Polymer Chemistry, 2011Co-Authors: Yusuke Hibi, Makoto Ouchi, Shinsuke Tokuoka, Takaya Terashima, Mitsuo SawamotoAbstract:For alternating repeat-unit Sequence via living radical polymerization, “template monomers” were designed and polymerized, where two polymerizable alkene (vinyl) functions [e.g., methacrylate (M) and acrylate (A)] were placed side by side at the 1,8-positions on a rigid naphthalene scaffold. Even for such a divinyl monomer, highly selective intramolecular radical propagation was achieved with metal-catalyzed living radical polymerization systems, to give linear Controlled polymers without cross-linking. The naphthalene template was cleaved viahydrolysis from the resultant polymer, and subsequently methylated for Sequence characterization. 1H NMR analysis demonstrated that the polymers consisted of highly alternating Sequences (A-M-A: >80%), practically free from homo triad Sequences (M-M-M).
Makoto Ouchi - One of the best experts on this subject based on the ideXlab platform.
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Construction methodologies and Sequence-oriented properties of Sequence-Controlled oligomers/polymers generated via radical polymerization
Polymer Journal, 2020Co-Authors: Makoto OuchiAbstract:The chain-growth polymerization mechanism is essentially unsuitable for Sequence Control due to the statistical propagation feature. However, the development of reversible-deactivation radical polymerization (RDRP) has opened the door to Sequence Control for carbon–carbon bond-based synthetic polymers carrying various pendant groups on their repeating units. Our group has developed some methodologies and concepts for the synthesis of Sequence-Controlled oligomers/polymers via radical polymerization. It is crucial to introduce some additional components into the initiator and/or the monomer for RDRP, and in most cases, these components are designed to be removed or transformable afterward. This review focuses on the methodologies we have recently developed for Sequence regulation via radical polymerization processes and the Sequence-oriented properties of the resultant Sequence-Controlled polymers. The chain-growth polymerization mechanism is essentially unsuitable for Sequence Control due to its statistical propagation feature. However, the development of reversible-deactivation radical polymerization has opened the door to the Sequence Control. Our group has developed some methodologies and concepts for the synthesis of Sequence-Controlled oligomers/polymers via radical polymerization: it is crucial to introduce some additional components into the initiator and/or the monomer for reversible-deactivation radical polymerization and in most cases these components are designed to be removed or transformable afterward.
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Sequence-Controlled polymers via reversible-deactivation radical polymerization
Polymer Journal, 2018Co-Authors: Makoto Ouchi, Mitsuo SawamotoAbstract:The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to Control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘Sequence Control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined Sequence like peptides in nature. Herein, some methodologies to realize Sequence Control based on RDRP are reviewed. The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only in Controlling the molecular weight and terminal structures but also in the precise synthesis of copolymers. An additional design for Controlled propagation via RDRP could lead to Control of the order of repeating units, that is, the ‘Sequence Control’, which has been recognized as the ultimate Control of precision polymerizations. In this review article, some concepts and methodologies are summarized for synthesizing Sequence-Controlled polymers based on RDRP.
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Sequence-Controlled polymers via reversible-deactivation radical polymerization
Polymer Journal, 2017Co-Authors: Makoto Ouchi, Mitsuo SawamotoAbstract:The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to Control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘Sequence Control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined Sequence like peptides in nature. Herein, some methodologies to realize Sequence Control based on RDRP are reviewed.
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a strategy for Sequence Control in vinyl polymers via iterative Controlled radical cyclization
Nature Communications, 2016Co-Authors: Yusuke Hibi, Makoto Ouchi, Mitsuo SawamotoAbstract:There is a growing interest in Sequence-Controlled polymers toward advanced functional materials. However, Control of side-chain order for vinyl polymers has been lacking feasibility in the field of polymer synthesis because of the inherent feature of chain-growth propagation. Here we show a general and versatile strategy to Control Sequence in vinyl polymers through iterative radical cyclization with orthogonally cleavable and renewable bonds. The proposed methodology employs a repetitive and iterative intramolecular cyclization via a radical intermediate in a one-time template with a radical-generating site at one end and an alkene end at the other, each of which is connected to a linker via independently cleavable and renewable bonds. The unique design specifically allowed Control of radical addition reaction although inherent chain-growth intermediate (radical species) was used, as well as the iterative cycle and functionalization for resultant side chains, to lead to Sequence-Controlled vinyl polymers (or oligomers).
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design of ab divinyl template monomers toward alternating Sequence Control in metal catalyzed living radical polymerization
Polymer Chemistry, 2011Co-Authors: Yusuke Hibi, Makoto Ouchi, Shinsuke Tokuoka, Takaya Terashima, Mitsuo SawamotoAbstract:For alternating repeat-unit Sequence via living radical polymerization, “template monomers” were designed and polymerized, where two polymerizable alkene (vinyl) functions [e.g., methacrylate (M) and acrylate (A)] were placed side by side at the 1,8-positions on a rigid naphthalene scaffold. Even for such a divinyl monomer, highly selective intramolecular radical propagation was achieved with metal-catalyzed living radical polymerization systems, to give linear Controlled polymers without cross-linking. The naphthalene template was cleaved viahydrolysis from the resultant polymer, and subsequently methylated for Sequence characterization. 1H NMR analysis demonstrated that the polymers consisted of highly alternating Sequences (A-M-A: >80%), practically free from homo triad Sequences (M-M-M).
Yusuke Hibi - One of the best experts on this subject based on the ideXlab platform.
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a strategy for Sequence Control in vinyl polymers via iterative Controlled radical cyclization
Nature Communications, 2016Co-Authors: Yusuke Hibi, Makoto Ouchi, Mitsuo SawamotoAbstract:There is a growing interest in Sequence-Controlled polymers toward advanced functional materials. However, Control of side-chain order for vinyl polymers has been lacking feasibility in the field of polymer synthesis because of the inherent feature of chain-growth propagation. Here we show a general and versatile strategy to Control Sequence in vinyl polymers through iterative radical cyclization with orthogonally cleavable and renewable bonds. The proposed methodology employs a repetitive and iterative intramolecular cyclization via a radical intermediate in a one-time template with a radical-generating site at one end and an alkene end at the other, each of which is connected to a linker via independently cleavable and renewable bonds. The unique design specifically allowed Control of radical addition reaction although inherent chain-growth intermediate (radical species) was used, as well as the iterative cycle and functionalization for resultant side chains, to lead to Sequence-Controlled vinyl polymers (or oligomers).
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design of ab divinyl template monomers toward alternating Sequence Control in metal catalyzed living radical polymerization
Polymer Chemistry, 2011Co-Authors: Yusuke Hibi, Makoto Ouchi, Shinsuke Tokuoka, Takaya Terashima, Mitsuo SawamotoAbstract:For alternating repeat-unit Sequence via living radical polymerization, “template monomers” were designed and polymerized, where two polymerizable alkene (vinyl) functions [e.g., methacrylate (M) and acrylate (A)] were placed side by side at the 1,8-positions on a rigid naphthalene scaffold. Even for such a divinyl monomer, highly selective intramolecular radical propagation was achieved with metal-catalyzed living radical polymerization systems, to give linear Controlled polymers without cross-linking. The naphthalene template was cleaved viahydrolysis from the resultant polymer, and subsequently methylated for Sequence characterization. 1H NMR analysis demonstrated that the polymers consisted of highly alternating Sequences (A-M-A: >80%), practically free from homo triad Sequences (M-M-M).
Geoffrey W Coates - One of the best experts on this subject based on the ideXlab platform.
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polymerization of enantiopure monomers using syndiospecific catalysts a new approach to Sequence Control in polymer synthesis
Journal of the American Chemical Society, 2009Co-Authors: John W Kramer, Daniel S Treitler, Erin W Dunn, Pascal Castro, Thierry Roisnel, Christophe M Thomas, Geoffrey W CoatesAbstract:The ring-opening polymerization of a mixture of enantiomerically pure but different monomers using an yttrium complex as initiator proceeds readily at room temperature to give the corresponding highly alternating polyester.
Pengfei Zhang - One of the best experts on this subject based on the ideXlab platform.
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Supramolecular Polymerization with Dynamic Self-Sorting Sequence Control
Macromolecules, 2019Co-Authors: Xiujuan Shi, Xiaodong Zhang, Haoke Zhang, Peifa Wei, Junkai Liu, Hao Xing, Hui-qing Peng, Jacky Wing Yip Lam, Pengfei ZhangAbstract:Synthetic polymerization and supramolecular polymerization with Sequence Control are far from an easy task. Herein, a narcissistic self-sorting supramolecular polymer is prepared with a Sequence of (−AA–BB−)n by using cucurbit[8]uril (CB[8])-based ternary complexes as supramolecular monomers, which are spontaneously formed from heteroditopic AB-type guest and CB[8]. Supramolecular polymerization and the structural changes at each stage of polymerization have been successfully demonstrated by NMR, UV–vis, and fluorescence spectra. The self-sorting starts from the second step of polymerization after the formation of different ternary complexes as supra-monomers. The dynamic supramolecular interactions and the thermodynamic stability of the host–guest complexes are found to be the crucial factors to drive the Sequence Control of the supramolecular polymers. Furthermore, the water-soluble supramolecular polymer is red-emissive and can serve as a fluorescent sensor to detect morphine in artificial urine with c...
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Supramolecular Polymerization with Dynamic Self-Sorting Sequence Control
2019Co-Authors: Shi Xiujuan, Xiaodong Zhang, Haoke Zhang, Peifa Wei, Junkai Liu, Hao Xing, Hui-qing Peng, Jacky Wing Yip Lam, Pengfei ZhangAbstract:Synthetic polymerization and supramolecular polymerization with Sequence Control is far from an easy task. Herein, a narcissistic self-sorting supramolecular polymer is prepared with a Sequence of (−AA−BB−)n by using cucur-bit[8]uril (CB[8])-based ternary complexes as supramolecular monomers, which are spontaneously formed from starting materials of heteroditopic AB-type guest and CB[8]. The process of supramolecular polymerization and their structural changes at each stage of polymerization have been successfully demonstrated by NMR, UV-Vis and fluorescence spectra. The self-sorting starts from the second step of polymerization after the formation of different ternary complexes as supra-monomers. The dynamic supramolecular interactions and the thermodynamic stability of the host–guest complexes are found to be the crucial factors to drive the Sequence Control of the supramolecular polymers. Furthermore, the water-soluble supramolecular polymer is red-emissive, which can serve as fluorescent sensor to detect morphine in artificial urine with considerable stability, sensitivity and accuracy. And it can also distinguish heroin and morphine, which are two kinds of opioids with similar structures.
