Viologen derivatives with extended π-conjugation structures: From supra-/molecular building blocks to organic porous materials

• Published in: Chinese chemical letters 2020-07, Vol.31 (7), p.1757-1767
• Main Authors: Zhou, Xiao-He, Fan, Yu, Li, Wan-Xia, Zhang, Xiang, Liang, Rong-Ran, Lin, Feng, Zhan, Tian-Guang, Cui, Jiecheng, Liu, Li-Juan, Zhao, Xin, Zhang, Kang-Da
• Format: Article
• Language: English
• Subjects: Ionic organic porous materials; Self-assembly; Supramolecular organic frameworks; Supramolecular polymers; π-Conjugated viologens
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2019.12.039

This review highlights the recent progresses in the development of viologen derivatives with extended π-conjugation structures, including their applications in electrochromic and energy storage materials, supramolecular self-assembly as well as organic porous materials. [Display omitted] Recently, increasing attention has been paid on extending the π-conjugation structures of viologens (1,1′-disubstituted-4,4′-bipyridylium salts) by incorporating planar aromatic units into the bipyridinium backbones. Various viologen derivatives with extended π-conjugation structures have been synthesized, including the N-termini aromatic substituted viologens, the extended π-conjugated viologens (denoted as ECVs) as well as the π-conjugated oligomeric viologens (denoted as COVs). These compounds typically exhibit interesting properties distinguished from those of an isolated viologen unit, which make them as new class of electron deficient supra-/molecular building blocks in supramolecular chemistry and materials science. In this review, we would like to highlight the recent advances of viologen derivatives with extended π-conjugation structures in versatile applications ranging from electrochromic and energy storage materials, the ECV/COV-based supramolecular self-assembly systems including the linear supramolecular polymers and 2D/3D supramolecular organic frameworks (SOFs), to the viologen-based covalent organic frameworks (COFs)/networks. We hope this review will serve as an in-time summary worthy of referring, more importantly, to provide inspiration in the rational design of novel molecules with unexplored properties and functions.