Azulene-A Bright Core for Sensing and Imaging

Azulene is a hydrocarbon isomer of naphthalene known for its unusual colour and fluorescence properties. Through the harnessing of these properties, the literature has been enriched with a series of chemical sensors and dosimeters with distinct colorimetric and fluorescence responses. This review focuses specifically on the latter of these phenomena. The review is subdivided into two sections. Section one discusses turn-on fluorescent sensors employing azulene, for which the literature is dominated by examples of the unusual phenomenon of azulene protonation-dependent fluorescence. Section two focuses on fluorescent azulenes that have been used in the context of biological sensing and imaging. To aid the reader, the azulene skeleton is highlighted in blue in each compound.

Automated summary

Azulene, a hydrocarbon isomer of naphthalene, is known for its unusual color and fluorescence properties. Researchers have utilized these properties to develop a series of chemical sensors and dosimeters with distinct colorimetric and fluorescence responses. This review specifically focuses on the use of azulene in fluorescent sensors and biological sensing and imaging, highlighting the unique phenomenon of azulene protonation-dependent fluorescence in the literature.