Optically Active Cyclic Oligomers Based on Planar Chiral [2.2]Paracyclophane
Optically Active Cyclic Oligomers Based on Planar Chiral [2.2]Paracyclophane
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基于平面手性[2.2]对环芳烷的光学活性环状低聚物
DOI：
10.1002/asia.202101267
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Yasuhiro Morisaki
中科院分区：
文献类型：
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作者：
Kentaro Tanaka;Ryo Inoue;Yasuhiro Morisaki
以对映体纯的4，7，12，15-四取代[2.2]对环芳烷为手性结构单元，合成了光学活性的环状二聚体、三聚体和四聚体，其中对亚芳基-乙炔基是堆叠的.所有分子在其吸收带的镜像光谱中都表现出明显的Cotton效应，并且（Rp）-和（Sp）-异构体的最长波长的信号分别为正和负。它们的圆偏振发光（CPL）符号与第一个Cotton效应相对应。对于所有分子，分子轨道在激发态中定位于堆叠的dp-亚芳基-乙炔基之一中，导致类似的光致发光行为。虽然环状二聚体不发射CPL，但环状三聚体和四聚体表现出强烈的CPL发射，具有相对较高的不对称因子，约为10−3。通过含时密度泛函理论计算再现了它们的光学和手光学性质。
Optically active cyclic dimer, trimer, and tetramer, in which thep‐arylene‐ethynylenes were stacked, were prepared using enantiopure 4,7,12,15‐tetrasubstituted [2.2]paracyclophane as the chiral building block. All molecules exhibited clear Cotton effects in their absorption bands with mirror image spectra, and the signals of the longest wavelengths of the (Rp)‐ and (Sp)‐isomers were positive and negative, respectively. Their circularly polarized luminescence (CPL) signs corresponded with the those of the first Cotton effect. For all molecules, molecular orbitals were localized in one of the stackedp‐arylene‐ethynylenes in the excited states, resulting in a similar photoluminescence behavior. Although the cyclic dimer did not emit CPL, the cyclic trimer and tetramer exhibited intense CPL emissions with a relatively high dissymmetry factor in the order of 10−3. Their optical and chiroptical properties were reproduced by time‐dependent density functional theory calculations.