Thermoresponsive On−Off Switching of Chiroptical Property Induced in Poly(4‘-ethynylbenzo-15-crown-5)/α-Amino Acid System
Thermoresponsive On−Off Switching of Chiroptical Property Induced in Poly(4‘-ethynylbenzo-15-crown-5)/α-Amino Acid System
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DOI：
10.1021/ma060376i
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发表时间：
2006-05
期刊：
影响因子：
5.5
通讯作者：
R. Sakai;I. Otsuka;T. Satoh;R. Kakuchi;and Harumi Kaga;T. Kakuchi
中科院分区：
文献类型：
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作者：
R. Sakai;I. Otsuka;T. Satoh;R. Kakuchi;and Harumi Kaga;T. Kakuchi
顺式-反式聚（4 '-乙炔基苯并-15-冠-5）（2）是由4'-乙炔基苯并-15-冠-5与Rh（nbd）BPh 4聚合而成，它是一种具有手性开关性质的温敏材料。在l-苯甘氨酸高氯酸盐存在下，2的圆二色性（CD）光谱中（l-Pgly·HClO 4）在-30 °C下，在300至550 nm范围内观察到强度为+2.96 × 104 deg cm 2 dmol-1的大的Cotton效应，对应于共轭聚合物主链的吸收，表明2形成单手螺旋结构是由l-Pgly·HClO 4的主客体络合引发的。然而，诱导CD（ICD）强度随着温度的升高而显著降低，在30 °C或更高温度下几乎完全消失。此外，在−30 ° C和30 °C之间的交替温度调制导致ICD的可逆开关切换为2。
Cis-transoidal poly(4‘-ethynylbenzo-15-crown-5) (2) prepared by the polymerization of 4‘-ethynylbenzo-15-crown-5 with Rh(nbd)BPh4 has been used as a thermoresponsive material with a chiral on−off switching property. In the circular dichroism (CD) spectrum of 2 in the presence of the perchloric acid salt of l-phenylglycine (l-Pgly·HClO4) at −30 °C, a large Cotton effect with an intensity of +2.96 × 104 deg cm2 dmol-1 was observed in the range from 300 to 550 nm corresponding to the absorption of the conjugated polymer backbone, indicating that 2 formed the one-handed helical structure triggered by the host−guest complexation with l-Pgly·HClO4. However, the induced CD (ICD) intensity significantly decreased with the increasing temperature and almost completely disappeared at 30 °C or over. Furthermore, an alternate temperature modulation between −30 and 30 °C brought about the reversible on−off switching of the ICD of 2.