Synthesis, Structures and Properties of Trioxa[9]circulene and Diepoxycyclononatrinaphthalene
Daiyue Yang, Ka Man Cheung, Qiyong Gong, Li Zhang, Lulin Qiao, Xiao Chen, Zhifeng Huang, Qian Miao
Abstract
Abstract This article presents trioxa[9]circulene ( 3 ) as a novel member of hetero[ n ]circulenes. Its synthesis began with the synthesis of dimethoxydioxa[8]helicene ( 5 ) and used dimethoxydiepoxycyclononatrinaphthalene ( 4 ) as a key intermediate, despite the condensation reaction predominantly yielding a 1,4‐addition byproduct. The structures and properties of 3 – 5 were extensively investigated using experimental and computational methods. Analysis of the crystal structures reveal elongation of the internal C−C bonds in the nine‐membered ring of 3 compared to 4 and 5 . Computational studies demonstrate the remarkable flexibility of trioxa[9]circulene's saddle‐shaped polycyclic framework, while the other two compounds are rigid with large racemization barriers. Optically pure forms of 4 and 5 exhibit absorption and luminescence dissymmetry factors on the order of 10 −2 , with smaller values observed for compound 4 . In the crystal structures, molecules of 3 stack to form columns with remarkable π–π overlap, and the π–π interactions of 4 exhibit short intermolecular C‐to‐C contacts. Consequently, the solution‐processed film of 4 functioned as a p‐type organic semiconductor in field effect transistors.