Temperature-Driven Planar Chirality Switching of a Pillar[5]arene-Based Molecular Universal Joint.
Temperature-Driven Planar Chirality Switching of a Pillar[5]arene-Based Molecular Universal Joint.
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柱[5]芳烃基分子万向节的温度驱动平面手性切换。
DOI：
10.1002/anie.201702542
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Yang Cheng
中科院分区：
文献类型：
--
作者：
Yao Jiabin;Wu Wanhua;Liang Wenting;Feng Yujun;Zhou Dayang;Chruma Jason J;Fukuhara Gaku;Mori Tadashi;Inoue Yoshihisa;Yang Cheng
通过单晶X射线衍射研究了一种对映体纯的双环柱[5]芳烃基分子万向接头（MUJ），首次通过圆二色性光谱明确指定了平面手性柱[5]芳烃的绝对构型。至关重要的是，MUJ的绝对配置是可逆的温度切换，伴随着符号反转的各向异性因子的变化多达0.03，这是有史以来最大的值。在机械上，MUJ的可逆手性转换由稠环的穿线/脱线运动驱动，因此取决于环的大小和性质以及所用溶剂，反映了环与柱[5]芳烃的自络合、对被排除环的溶剂化和溶剂分子在空腔中的包含之间的临界平衡。
The study of an enantiopure bicyclic pillar[5]arene-based molecular universal joint (MUJ) by single-crystal X-ray diffraction allowed for the first time the unequivocal assignment of the absolute configuration of a planar chiral pillar[5]arene by circular dichroism spectroscopy. Crucially, the absolute configuration of the MUJ was switched reversibly by temperature, with an accompanying sign inversion of the anisotropy factor that varied by as much as 0.03, which is the largest value ever reported. Mechanistically, the reversible chirality switching of the MUJ is driven by the threading/dethreading motion of the fused ring and hence is dependent on both the size and nature of the ring and the solvent employed, reflecting the critical balance between the self-complexation of the ring by pillar[5]arene, the solvation to the excluded ring, and the inclusion of solvent molecules in the cavity.