Highly sensitive sensory materials for fluoride ions based on the dithieno[3,2-b:2',3'-d]phosphole system

structure: see text]. The newly developed functionalization of an unsubstituted dithieno3,2-b:2',3'-d]phosphole at the 5,5'-positions gives access to bis(pinacoleboryl) species that can be utilized as sensory materials for fluoride ions. The fluoride-triggered response of the air- and moisture-stable boryl-functionalized dithienophosphole oxide manifests itself in the generation of a new fluorescence emission that can be detected at very low analyte concentrations (ppm) or even with the naked eye upon irradiation with UV light (366 nm).