Li Guangwu, Matsuno Taisuke, Han Yi, Phan Hoa, Wu Shaofei, Jiang Qing, Zou Ya, Isobe Hiroyuki, Wu Jishan
Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
Angew Chem Int Ed Engl. 2020 Jun 8;59(24):9727-9735. doi: 10.1002/anie.202002447. Epub 2020 Apr 7.
Synthesis of fully conjugated cyclophanes containing large-size polycyclic aromatics is challenging. Now, three benzidine-linked, hexa-peri-hexabenzocoronene (superbenzene)-based ortho-, para-, and meta-cyclophanes are synthesized through intermolecular Yamamoto coupling reaction of structurally pre-organized precursors. Subsequent oxidative dehydrogenation gave the corresponding quinoidal benzidine-linked cyclophanes. Their geometries were confirmed by X-ray crystallographic analysis and their electronic properties were investigated by electronic absorption, cyclic voltammetry, and DFT calculations. The quinoidal benzidine-linked cyclophanes show thermally populated paramagnetic activity with a relatively large singlet-triplet energy gap. Two enantiomers for the ortho-cyclophanes (1-NH and 1-N) were isolated and their chiral figure-of-eight macrocyclic structures were identified. The cage-like cyclophanes 2-NH and 3-NH with concave surface can selectively encapsulate fullerene C .
合成含有大尺寸多环芳烃的完全共轭环芳是一项具有挑战性的任务。现在，通过结构预组织的前体的分子间山本偶联反应，合成了三种基于联苯胺连接的六并六苯并蔻（超苯）的邻位、对位和间位环芳。随后的氧化脱氢反应得到了相应的醌型联苯胺连接的环芳。通过X射线晶体学分析确定了它们的几何结构，并通过电子吸收、循环伏安法和密度泛函理论计算研究了它们的电子性质。醌型联苯胺连接的环芳显示出热填充的顺磁活性，具有相对较大的单重态-三重态能隙。分离出了邻位环芳（1-NH和1-N）的两种对映体，并确定了它们的手性8字形大环结构。具有凹面的笼状环芳2-NH和3-NH可以选择性地包封富勒烯C 。
