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篇目详细内容 |
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【篇名】 |
Designed synthesis and chiroptical properties of regioregular poly(p-phenyleneethynylene-alter-m-phenyleneethynylene) bearing (-)-trans-myrtanoxyl side groups |
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【刊名】 |
Frontiers of Chemistry in China |
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【刊名缩写】 |
Front. Chem. China |
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【ISSN】 |
1673-3495 |
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【EISSN】 |
1673-3614 |
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【DOI】 |
10.1007/s11458-009-0018-7 |
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【出版社】 |
Higher Education Press and Springer-Verlag |
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【出版年】 |
2009 |
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【卷期】 |
4
卷1期 |
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【页码】 |
93-103
页,共
11
页 |
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【作者】 |
Xiangfeng LI;
Chusheng LI;
Jiang LU;
Hui LIANG;
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【关键词】 |
chiral; conjugated polymer; optical activity; circular dichroism |
【摘要】 |
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Two regioregular poly(p-phenyleneethynylene-alter-m-phenyleneethynylene)s bearing (-)-trans-myrtanoxyl side groups with different substitution patterns were designed and synthesized, e.g. Myr-PMPE-1 and Myr-PMPE-2. In Myr-PMPE-1, the side chiral groups are distributed uniformly along the backbone. In Myr-PMPE-2, the distribution of the side chiral groups is alternatively crowded and loose. Both of these two polymers show no CD signal in solutions because of their good solubility. The investigations of chiroptical properties of these two polymers were carried out in the form of spin-coated films. The films were annealed above the glass temperature of the corresponding polymer, and the effects of annealing temperature and time on the properties of the films were investigated by UV-Vis absorption, fluorescence and circular dichroism spectra. The results show that annealing treatment had no significant effect on the properties of Myr-PMPE-1, including UV-Vis absorption, fluorescence and optical activity. The maximum absolute value of dissymmetry factor (|gmax|) was 1.62 × 10−4. On the other hand, annealing treatment significantly affected the properties of Myr-PMPE-2. Without annealing or being annealed below 100°C, Myr-PMPE-2 films show almost no Cotton effect. In contrast, when annealed above 120°C, the absorption and emission of Myr-PMPE-2 films slightly red shifted with increasing annealing temperature and annealing time. Most importantly, the intensity of CD signals increased significantly and the optical activity of Myr-PMPE-2 films markedly increased. After annealing at 140°C for 4 h, the |gmax| of Myr-PMPE-2 films was increased up to 3.07 × 10−3, about one order of magnitude higher than that of Myr-PMPE-1 films. |
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