A Blueprint for Transforming Indigos to Photoresponsive Molecular Tools

• Published in: Chemistry : a European journal 2023-08, Vol.29 (43), p.e202300981-n/a
• Main Authors: Huang, Chung‐Yang (Dennis), Hecht, Stefan
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Chemistry; dyestuffs; E/Z isomerization; Electron transfer; Indigo; Molecular structure; Photochemicals; photochromism
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202300981

Indigo, one of the most ancient and abundant dyes in human history, has recently emerged as a potential functional motif due to its intriguing photochemical properties. This review aims to provide insights into both the preparation of these molecules and their utilization in molecular systems. First, the synthesis of the indigo core as well as available methods to derivatize indigo are described to outline synthetic strategies to build the desired molecular structures. Then, the photochemical behavior of indigos is discussed, with particular focus on E‐Z photoisomerization and photoinduced electron transfer. Connections between the molecular structures and their photochemical properties are highlighted and serve as guiding principles for designing indigos to be applied as photoresponsive tools. Indigo dye is one of the most iconic compounds connecting chemistry to our society. In addition to providing the characteristic blue color, indigos display fascinating photochemical properties. This Review first discusses the synthetic construction and derivatization of indigos. Then their photoswitching and photoinduced electron transfer behaviors are described to showcase the utility of indigos as photoresponsive molecular tools.