Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama 700-0005, Japan.
Org Biomol Chem. 2010 Nov 7;8(21):4997-5006. doi: 10.1039/c0ob00290a. Epub 2010 Sep 13.
Three types of cyclic oligomers consisting of five or six 1,8-anthrylene units with acetylene linkers were synthesized by macrocyclization of the corresponding acyclic precursors with coupling reactions. DFT calculations at the M05/3-21G level revealed that the pentamers had a relatively rigid structure with strained alkyne carbons. Meanwhile, out of several possible conformers the hexamers preferred to take parallelogram-prism structures due to transannular π···π interactions, and conformational interconversions via rotation about the acetylene axes took place rapidly at room temperature. NMR spectra and electronic spectra are discussed on the basis of molecular structures. The enantiomers of the chiral hexamer with one diacetylene linker were resolved by chiral HPLC, and showed optical activity.
三种由五个或六个 1,8-蒽单元与乙炔连接体组成的环状低聚物通过相应的非环状前体的大环化与偶联反应合成。在 M05/3-21G 水平的 DFT 计算表明，五聚体具有相对刚性的结构，具有应变的炔碳原子。同时，在几种可能的构象中，由于环间π···π相互作用，六聚体更喜欢采取平行六面体形-棱柱形结构，并且通过围绕乙炔轴的旋转进行的构象互变在室温下迅速发生。基于分子结构讨论了 NMR 光谱和电子光谱。通过手性 HPLC 拆分了具有一个二乙炔连接体的手性六聚体的对映异构体，并表现出光学活性。
