Development and photophysical properties of a novel BODIPY-Thiazole receptor for Ba²⁺ detection: hydrolysis mechanisms and cellular applications

A novel BODIPY – thiazole-based chemodosimeter, (E)-N-(benzo[d]thiazol-2-yl)-1-(5,5-difluoro-1,3,7,9,10-pentamethyl-5 H-4λ4,5λ4-dipyrrolo[1,2-c:2′,1′-f][1,3,2] diazaborinin-2-yl) methanimine (R1) – was rationally designed and successfully synthesised by refluxing 5,5-difluoro-1,3,7,9,10-pentamethyl-5 H-4λ4,5λ4 -dipyrrolo[1,2-c:2′,1′-f][1,3,2] diazaborinin-2-carbaldehyde (compound 1) with 2-aminobenzothiazole in methanol. R1 was developed for the selective detection of Ba2+ ions in a CH3CN/H2O medium. The sensing mechanism involves Ba2+ -induced hydrolysis of the imine bond in R1, resulting in the regeneration of compound 1, which is responsible for the observed fluorescence response. Upon the addition of Ba2+ ions, R1 exhibited a highly selective ‘turn-on’ fluorescence response with a new emission band at 514 nm and approximately 1000-fold intensity enhancement. The limit of detection for Ba2+ was determined to be as low as 10−8 M. Furthermore, R1 showed good cytocompatibility and was successfully applied as a fluorescent probe for the detection of Ba2+ ions in MCF-7 cells.