Pub Date : 2025-07-31eCollection Date: 2025-12-22DOI: 10.1021/prechem.5c00055
Di Wang, Wei Li, Junjie Cheng, Xiangxiang Xu, Xini Chu, Zeyu Feng, Nana Sheng, Luxuan Lin, Hongli Zhang, Xin Chen, Gang Zou
The isomerization of pendant groups plays a crucial role in modulating helical structures and biological activity in both biomacromolecule and dynamic helical conjugated polymers. While the effects of solvents, pH, and temperature on pendant isomerization and helix preference have been extensively studied, the combined influence of pendant isomerization and enantiomeric excess remains largely unexplored. Herein, we report a dynamic helical poly-(phenylacetylene) (PPA) system, poly-[Dr -co-L(1-r)], in which the helix preference is dictated and nonlinearly amplified via the "majority rule" mechanism at low temperatures. Remarkably, temperature-triggered pendant isomerization can override this helix preference, leading to an "abnormal majority rule" behavior. By harnessing these dual effects, precise helix regulation is achieved, enabling helix inversion at high enantiomeric excess and chiral sustenance at low enantiomeric excess. A bifurcation point in helix preference facilitates the orthogonal control of polymer helicity, paving the way for programmable circularly polarized luminescence microarrays, with potential applications in information encoding and anticounterfeiting technologies. These findings provide a strategy for fine-tuning dynamic helical polymer structures.
悬垂基团的异构化在调节生物大分子和动态螺旋共轭聚合物的螺旋结构和生物活性方面起着至关重要的作用。虽然溶剂、pH和温度对悬垂异构化和螺旋偏好的影响已经被广泛研究，但悬垂异构化和对映体过量的综合影响在很大程度上仍未被探索。在此，我们报道了一个动态的螺旋聚（苯乙炔）（PPA）体系，聚-[D r -co- l (1-r)]，在低温下，通过“多数规则”机制，螺旋偏好被决定和非线性放大。值得注意的是，温度触发的垂坠异构化可以覆盖这种螺旋偏好，导致“异常多数规则”行为。通过利用这些双重效应，可以实现精确的螺旋调节，在高对映体过剩时实现螺旋反转，在低对映体过剩时实现手性维持。螺旋偏好的分叉点有助于聚合物螺旋度的正交控制，为可编程圆偏振发光微阵列铺平了道路，在信息编码和防伪技术方面具有潜在的应用前景。这些发现为动态螺旋聚合物结构的微调提供了一种策略。
{"title":"Helix Regulation of Poly(phenylacetylene)s through the Interplay between Enantiomeric Excess and Temperature-Triggered Pendant Isomerization.","authors":"Di Wang, Wei Li, Junjie Cheng, Xiangxiang Xu, Xini Chu, Zeyu Feng, Nana Sheng, Luxuan Lin, Hongli Zhang, Xin Chen, Gang Zou","doi":"10.1021/prechem.5c00055","DOIUrl":"10.1021/prechem.5c00055","url":null,"abstract":"<p><p>The isomerization of pendant groups plays a crucial role in modulating helical structures and biological activity in both biomacromolecule and dynamic helical conjugated polymers. While the effects of solvents, pH, and temperature on pendant isomerization and helix preference have been extensively studied, the combined influence of pendant isomerization and enantiomeric excess remains largely unexplored. Herein, we report a dynamic helical poly-(phenylacetylene) (PPA) system, poly-[<i>D</i> <sub><i>r</i></sub> -<i>co</i>-<i>L</i> <sub>(1-<i>r</i>)</sub>], in which the helix preference is dictated and nonlinearly amplified via the \"majority rule\" mechanism at low temperatures. Remarkably, temperature-triggered pendant isomerization can override this helix preference, leading to an \"abnormal majority rule\" behavior. By harnessing these dual effects, precise helix regulation is achieved, enabling helix inversion at high enantiomeric excess and chiral sustenance at low enantiomeric excess. A bifurcation point in helix preference facilitates the orthogonal control of polymer helicity, paving the way for programmable circularly polarized luminescence microarrays, with potential applications in information encoding and anticounterfeiting technologies. These findings provide a strategy for fine-tuning dynamic helical polymer structures.</p>","PeriodicalId":29793,"journal":{"name":"Precision Chemistry","volume":"3 12","pages":"767-776"},"PeriodicalIF":6.2,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12728750/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145834951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The precise synthesis of the industrial bactericide N-butyl-1,2-benzisothiazolin-3-one (BBIT) is primarily achieved through catalytic N-alkylation reactions. In this study, a multistep ion-exchange approach was utilized to produce Cs+ modified LTA zeolites (Cs-LTA) as precise catalysts for the selective N-alkylation of 1,2-benzisothiazolin-3-one (BIT) using bromobutane, resulting in high-efficiency BBIT synthesis. A systematic optimization of ion-exchange cycles and calcination temperatures facilitated precise control over Cs+ dispersion and basic site density within the zeolite framework. XRD, XPS, CO2-TPD, and 27Al NMR characterizations verified that the incorporation of Cs+ enhanced both the strength of basicity and structural stability through covalent Si-O-Cs bonds, thereby minimizing metal leaching. Under optimized conditions, the Cs-LTA/3 catalyst achieved a BIT conversion rate of 99.21% and a BBIT selectivity of 92.67%. Notably, the catalyst maintained over 80% activity after five cycles, demonstrating superior performance compared to impregnated counterparts. In situ Raman spectroscopy and kinetic analyses revealed a synergistic mechanism: Cs+ activates the C-Br bond in bromobutane, producing an electron-deficient alkene intermediate, while the zeolitic basic sites dehydrogenate BIT to generate a nucleophilic amine species, collectively reducing the calcination energy barrier. This research establishes a sustainable catalytic system that overcomes the limitations of homogeneous bases and transition-metal catalysts, providing insights into the strategic design of zeolite-based catalysts for green organic synthesis.
{"title":"Precise N‑Alkylation via Cs-LTA Zeolites: Mechanistic Insights and Green Catalytic Synthesis of High-Yield BBIT through Ion-Exchange Optimization.","authors":"Haoyu Yao, Haiyan Luo, Hao Li, Min Li, Wenyuan Zhang, Xiangfeng Liang","doi":"10.1021/prechem.5c00057","DOIUrl":"https://doi.org/10.1021/prechem.5c00057","url":null,"abstract":"<p><p>The precise synthesis of the industrial bactericide N-butyl-1,2-benzisothiazolin-3-one (BBIT) is primarily achieved through catalytic N-alkylation reactions. In this study, a multistep ion-exchange approach was utilized to produce Cs<sup>+</sup> modified LTA zeolites (Cs-LTA) as precise catalysts for the selective N-alkylation of 1,2-benzisothiazolin-3-one (BIT) using bromobutane, resulting in high-efficiency BBIT synthesis. A systematic optimization of ion-exchange cycles and calcination temperatures facilitated precise control over Cs<sup>+</sup> dispersion and basic site density within the zeolite framework. XRD, XPS, CO<sub>2</sub>-TPD, and <sup>27</sup>Al NMR characterizations verified that the incorporation of Cs<sup>+</sup> enhanced both the strength of basicity and structural stability through covalent Si-O-Cs bonds, thereby minimizing metal leaching. Under optimized conditions, the Cs-LTA/3 catalyst achieved a BIT conversion rate of 99.21% and a BBIT selectivity of 92.67%. Notably, the catalyst maintained over 80% activity after five cycles, demonstrating superior performance compared to impregnated counterparts. In situ Raman spectroscopy and kinetic analyses revealed a synergistic mechanism: Cs<sup>+</sup> activates the C-Br bond in bromobutane, producing an electron-deficient alkene intermediate, while the zeolitic basic sites dehydrogenate BIT to generate a nucleophilic amine species, collectively reducing the calcination energy barrier. This research establishes a sustainable catalytic system that overcomes the limitations of homogeneous bases and transition-metal catalysts, providing insights into the strategic design of zeolite-based catalysts for green organic synthesis.</p>","PeriodicalId":29793,"journal":{"name":"Precision Chemistry","volume":"3 11","pages":"715-724"},"PeriodicalIF":6.2,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12648437/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145640403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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