期刊
MACROMOLECULES
卷 51, 期 1, 页码 34-41出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.macromol.7b02328
关键词
-
资金
- Basic Science Research Program through the National Research Foundation of Korea (NRF) - Korean government (MEST) [2017R1A2B4007348, 2017R1A6A3A11034225]
- National Research Foundation of Korea [2017R1A6A3A11034225, 2017R1A2B4007348] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Achiral poly(diphenylacetylene)s (PDPAs: pMe3, pEt3, piPr3, pMe2OD1, pMe2ODI, and mMe3) with different alkyl side chains at the para or meta position of the side phenyl ring were prepared to examine achiral-to-chiral transformations upon thermal annealing in a chiral solvent. All the para-substituted PDPAs showed significant circular dichroism (CD) enhancement upon annealing, whereas the meta-substituted polymer, mMe3, was inert to the same treatment. To investigate the kinetics, the asymmetric conformational change was monitored by observing the changes in the magnitude of circular polarization (g(CD)) or optical rotation. PDPAs with bulkier, round-shaped side groups (pEt3 and piPr3) had greater g(CD) values at equilibrium than pMe3 with a smaller side group. Moreover, the activation energy for the forward reaction (Ea(f)) was lower in the bulkier polymers than in pMe3 owing to enhanced miscibility with the chiral solvent. Similarly, the long alkyl chains of pMe2O1 and pMe2ODI acted as internal plasticizers to lower their Ea(f) values relative to that of pMe3, whereas their g(CD) values at equilibrium were smaller than that of pMe3. The kinetics of the achiral-to-chiral transformation is discussed in detail based on the spectroscopic changes observed during the annealing process.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据