Novel sulfonylurea fluorescence probes for antiproliferative activity, detection and imaging of fluoride ions in living cells

In this study, four novel triphenylpyrazoline 4-toluenesulfonylureas (PYSUs) were synthesized to develop potential anticancer drugs and fluorescent probes for the detection of F⁻ ions. The compounds were synthesized via a two-step microwave-assisted method. The antiproliferative activity of the PYSUs was tested against two cancer cell lines: HepG2 and MDA-MB-231. Among the compounds, 3a exhibited strong activity against both cell lines, while 3b showed strong activity against MDA-MB-231 cells but weaker inhibition of HepG2 cells. Furthermore, compound 3b was identified as the best fluorescent probe, with an increase in emission intensity in the presence of F⁻ ions from tetrabutylammonium fluoride (TBAF). In DMSO, the emission wavelength was found to be 518 nm (green) with an excitation wavelength of 469 nm. The limit of detection (LOD) was calculated to be 0.269 mM in the linear range of 5–10 mM. The interaction mechanism between F⁻ ions and compound 3b was further explored via DFT/TDDFT calculations. Additionally, fluorescent imaging of TBAF-incubated MDA-MB-231 and HepG2 cells confirmed the potential of PYSUs as fluorescent sensors for F⁻ ions in living cancer cells.