Tanaka Kentaro, Inoue Ryo, Morisaki Yasuhiro
Department of Applied Chemistry for Environment, School of Biological and Environmental Sciences, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan.
Chem Asian J. 2022 Jan 17;17(2):e202101267. doi: 10.1002/asia.202101267. Epub 2021 Dec 18.
Optically active cyclic dimer, trimer, and tetramer, in which the p-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 (R )- and (S )-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 stacked p-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 . Their optical and chiroptical properties were reproduced by time-dependent density functional theory calculations.
使用对映体纯的4,7,12,15-四取代[2.2]对环芳烷作为手性结构单元，制备了对亚苯基乙炔堆叠的旋光性环状二聚体、三聚体和四聚体。所有分子在其具有镜像光谱的吸收带中均表现出明显的科顿效应，并且(R)-和(S)-异构体最长波长的信号分别为正和负。它们的圆偏振发光(CPL)符号与第一个科顿效应的符号相对应。对于所有分子，分子轨道在激发态时定域于堆叠的对亚苯基乙炔之一中，从而导致相似的光致发光行为。尽管环状二聚体不发射CPL，但环状三聚体和四聚体表现出强烈的CPL发射，其不对称因子相对较高，约为10 。通过含时密度泛函理论计算再现了它们的光学和手性光学性质。
