Chapter 14: Chalcogen-based Probes

Recently, selenium and tellurium atoms have been incorporated in various fluorophores such as rhodamine, cyanine, fluorescein, BODIPY, coumarin, and BOPHY for the detection and quantification of different analytes of biochemical and environmental interest by fluorescence measurements. The relevance of the insertion of chalcogen atoms in fluorescent compounds refers to their excellent redox characteristics, conferring unique properties to the resulting compounds, as analytical/biochemical probes. Additionally, selenium plays pivotal roles in biochemical events interacting selectively with endogenous sulfur-based biomolecules. About tellurium, there are only rare reports of its occurrence in certain fungi when exposed to tellurium-rich environments. Besides that, contrary to certain comments, generically, tellurium (and many organic tellurides) present low or no toxicity. This chapter provides a summary of all reported organic chalcogenated (Se and Te) fluorescent sensors, focusing on those containing selenium or tellurium in their structure, used in the detection of important analytes from a biological and environmental point of view, including metallic ions, reactive oxygen species (ROS), reactive nitrogen species (RNS), and biothiols.