School of Chemical Engineering, National Technical University of Athens (NTUA), Laboratory of Organic Chemistry, 15780, Athens, Greece.
Department of Chemistry-Ångström Laboratory, Uppsala University, 751 20, Uppsala, Sweden.
Molecules. 2019 Dec 18;25(1):1. doi: 10.3390/molecules25010001.
Mono- and di-quaternized 4,4'-bipyridine derivatives constitute a family of heterocyclic compounds, which in recent years have been employed in numerous applications. These applications correspond to various disciplines of research and technology. In their majority, two key features of these 4,4'-bipyridine-based derivatives are exploited: their redox activity and their electrochromic aptitude. Contemporary materials and compounds encompassing these skeletons as building blocks are often characterized as multifunctional, as their presence often gives rise to interesting phenomena, e.g., various types of chromism. This research trend is acknowledged, and, in this review article, recent examples of multifunctional chromic materials/compounds of this class are presented. Emphasis is placed on solvent-/medium- and environment-responsive 4,4'-bipyridine derivatives. Two important classes of 4,4'-bipyridine-based products with solvatochromic and/or environment-responsive character are reviewed: viologens (i.e., ,-disubstituted derivatives) and monoquats (i.e., monosubstituted 4,4'-bipyridine derivatives). The multifunctional nature of these derivatives is analyzed and structure-property relations are discussed in connection to the role of these derivatives in various novel applications.
单-和二季铵化 4,4'-联吡啶衍生物构成了一类杂环化合物，近年来在众多应用中得到了应用。这些应用对应于研究和技术的各个领域。在这些基于 4,4'-联吡啶的衍生物中，大多数情况下利用了它们的两个关键特征：氧化还原活性和电致变色能力。包含这些骨架作为构建块的当代材料和化合物通常被描述为多功能的，因为它们的存在常常会引起有趣的现象，例如各种类型的变色。这种研究趋势得到了认可，在本文中，介绍了这类多功能变色材料/化合物的最新实例。重点是溶剂/介质和环境响应的 4,4'-联吡啶衍生物。本文综述了两类具有溶剂化变色和/或环境响应特性的基于 4,4'-联吡啶的产品：重氮盐（即，,-二取代衍生物）和单季铵盐（即，单取代 4,4'-联吡啶衍生物）。分析了这些衍生物的多功能性质，并结合这些衍生物在各种新应用中的作用讨论了结构-性质关系。
