Single molecular dual analyte thio-urea based probes for colorimetric Hg2+ and fluorometric AcO− detection and its’ application in bioimaging

Abstract

Two thio-urea based bifunctional probes (H2L1-S and H2L2-S) have been designed and fabricated for the colorimetric and fluorometric detection of mercury(II) and acetate ions respectively in DMSO media. Both the H2L1-S and H2L2-S were fully characterized by various spectroscopic techniques and the solid-state structure of H2L1-S was determined via single-crystal X-ray diffraction. The high sensitivity and selectivity of the probes for Hg2+ were achieved by the Hg2+ promoted desulfurization reactions utilizing the high thiophilic nature of mercury and was monitored by UV–vis spectroscopy. Most interestingly the desulfurized product was isolated and characterized by ESI-MS and single crystal X-ray diffraction. The probes H2L1-S and H2L2-S were found to be highly selective towards acetate ion (AcO−) in fluorescence channel. These probes showed a distinct fluorescence enhancement only in the presence of AcO− at 493 nm due to the inhibition of photo induced electron transfer (PET). Finally, the cytotoxicity study was carried out for biological application. The probe showed minimum cytotoxicity and was suitable for intracellular acetate ion imaging.