{"title":"Proton Transfer Anionic Polymerization of Methyl Methacrylate with Ligands for Dual Control of Molecular Weight and Tacticity","authors":"Katsutoshi Sagawa, Mineto Uchiyama*, Hironobu Watanabe, Chihiro Homma and Masami Kamigaito*, ","doi":"10.1021/prechem.4c0006610.1021/prechem.4c00066","DOIUrl":null,"url":null,"abstract":"<p >Dual control of the molecular weight and tacticity in proton transfer anionic polymerization (PTAP) of methyl methacrylate (MMA) was investigated by using various ligands in the presence of a bulky potassium base catalyst and an organic compound with a weakly acidic C–H bond as dormant species in toluene at 0 °C. The tacticity of the resulting poly(MMA) (PMMA) produced without ligands was nearly atactic (<i>rr</i>/<i>mr</i>/<i>mm</i> = 22/54/24). However, the use of 18-crown-6 as a ligand afforded predominantly syndiotactic PMMA (<i>rr</i> ≈ 58%), whereas the use of chiral bis(oxazoline) ligands gave slightly isotactic-rich PMMA (<i>mm</i> ≈ 32%). Molecular weight control of PMMA was achieved (<i>Đ</i> = 1.1–1.2) by adding 1,1-diphenylethanol as a reversible terminator while maintaining control of the tacticity with the above ligands. Stereoblock PMMA consisting of atactic and syndiotactic segments was successfully synthesized via sequential PTAP using macroinitiator/macro-CTA methods.</p>","PeriodicalId":29793,"journal":{"name":"Precision Chemistry","volume":"2 12","pages":"628–633 628–633"},"PeriodicalIF":0.0000,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/prechem.4c00066","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Precision Chemistry","FirstCategoryId":"1085","ListUrlMain":"https://pubs.acs.org/doi/10.1021/prechem.4c00066","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
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Abstract
Dual control of the molecular weight and tacticity in proton transfer anionic polymerization (PTAP) of methyl methacrylate (MMA) was investigated by using various ligands in the presence of a bulky potassium base catalyst and an organic compound with a weakly acidic C–H bond as dormant species in toluene at 0 °C. The tacticity of the resulting poly(MMA) (PMMA) produced without ligands was nearly atactic (rr/mr/mm = 22/54/24). However, the use of 18-crown-6 as a ligand afforded predominantly syndiotactic PMMA (rr ≈ 58%), whereas the use of chiral bis(oxazoline) ligands gave slightly isotactic-rich PMMA (mm ≈ 32%). Molecular weight control of PMMA was achieved (Đ = 1.1–1.2) by adding 1,1-diphenylethanol as a reversible terminator while maintaining control of the tacticity with the above ligands. Stereoblock PMMA consisting of atactic and syndiotactic segments was successfully synthesized via sequential PTAP using macroinitiator/macro-CTA methods.
期刊介绍：
Chemical research focused on precision enables more controllable predictable and accurate outcomes which in turn drive innovation in measurement science sustainable materials information materials personalized medicines energy environmental science and countless other fields requiring chemical insights.Precision Chemistry provides a unique and highly focused publishing venue for fundamental applied and interdisciplinary research aiming to achieve precision calculation design synthesis manipulation measurement and manufacturing. It is committed to bringing together researchers from across the chemical sciences and the related scientific areas to showcase original research and critical reviews of exceptional quality significance and interest to the broad chemistry and scientific community.
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