{"title":"Asymmetric Synthesis of Chiral Polyisocyanides from Achiral Monomers with Living Polymerization in a Liquid Crystal Reaction Field","authors":"Hiromasa Goto, Takuya Yonehara, Hiroki Hayashi, Shigeki Nimori, Reiji Kumai, Ryo Miyashita","doi":"10.1021/acs.macromol.4c01017","DOIUrl":null,"url":null,"abstract":"Enzymes and ribosomes play an important role in producing chiral biopolymers with precisely controlled molecular weights and helical properties, taking advantage of the asymmetric environment in the condensed state of a biological cell. This study demonstrates living polymerization in living cell-inspired chiral liquid crystals (LC) as a solvent for preparing preferentially one-handed helical poly(aryl isocyanide)s (PAIs) from achiral monomers with controlled molecular weights and narrow polydispersity. The rod-shaped aryl isocyanide monomers were designed to exhibit high compatibility with chiral host liquid crystal (LC) media. In polymerization, the main chain grows in the manner of living polymerization in the helical matrix by forming a one-handed helical structure. This represents the first-known study on helix sense-selective living polymerization of achiral monomers using cholesteric liquid crystal (CLC) medium as an environmentally structural chiral solvent. Polyisocyanides thus synthesized by the asymmetric living polymerization in cholesteric liquid crystals exhibited a lyotropic twist-bend nematic phase (N<sub>tb</sub>), as a form of side chain-type polymer. Magnetic orientation is carried out to obtain a domain-stretched form. Polymerization in the CLC imparts chirality to the resulting PAIs as atropisomers, and the chiral PAIs form an N<sub>tb</sub> via LC collective formation. In particular, the main chain forms a predominantly one-handed helical structure as an asymmetric structure, and the side chain drives an N<sub>tb</sub> arrangement for the entire shape. Therefore, the LC state of PAIs can be defined as the polymer N<sub>tb</sub>. Thus, the CLC as a reaction field has induced the formation of products showing a chiral polymer N<sub>tb</sub>. Uniaxially oriented solid polymer films with the N<sub>tb</sub> order were obtained using a magnetic field.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"20 1","pages":""},"PeriodicalIF":5.2000,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Macromolecules","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.macromol.4c01017","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Enzymes and ribosomes play an important role in producing chiral biopolymers with precisely controlled molecular weights and helical properties, taking advantage of the asymmetric environment in the condensed state of a biological cell. This study demonstrates living polymerization in living cell-inspired chiral liquid crystals (LC) as a solvent for preparing preferentially one-handed helical poly(aryl isocyanide)s (PAIs) from achiral monomers with controlled molecular weights and narrow polydispersity. The rod-shaped aryl isocyanide monomers were designed to exhibit high compatibility with chiral host liquid crystal (LC) media. In polymerization, the main chain grows in the manner of living polymerization in the helical matrix by forming a one-handed helical structure. This represents the first-known study on helix sense-selective living polymerization of achiral monomers using cholesteric liquid crystal (CLC) medium as an environmentally structural chiral solvent. Polyisocyanides thus synthesized by the asymmetric living polymerization in cholesteric liquid crystals exhibited a lyotropic twist-bend nematic phase (Ntb), as a form of side chain-type polymer. Magnetic orientation is carried out to obtain a domain-stretched form. Polymerization in the CLC imparts chirality to the resulting PAIs as atropisomers, and the chiral PAIs form an Ntb via LC collective formation. In particular, the main chain forms a predominantly one-handed helical structure as an asymmetric structure, and the side chain drives an Ntb arrangement for the entire shape. Therefore, the LC state of PAIs can be defined as the polymer Ntb. Thus, the CLC as a reaction field has induced the formation of products showing a chiral polymer Ntb. Uniaxially oriented solid polymer films with the Ntb order were obtained using a magnetic field.
期刊介绍：
Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.
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