Two Novel Fluorescent Probes as Systematic Sensors for Multiple Metal Ions: Focus on Detection of Hg.

Many precedents prove that fluorescent probes are promising candidates for detection of metal ions in the environment and biological systems. Herein, two novel photoinduced electron transfer (PET)-based fluorescent probes, and , were rationally synthesized by incorporating a triazolyl benzaldehyde moiety into the rhodamine 6G fluorophore. The optical properties of these probes were studied using an ultraviolet-visible (UV-vis) absorption spectrophotometer and a fluorescence spectrophotometer. Through the analysis of the test results, it is concluded that the selectivity and sensitivity of these two probes to Hg are better than to other metal ions (Ag, Al, Ba, Cd, Co, Cu, Cr, Fe, Ga, K, Mg, Na, Ni, Pb, and Zn). According to the standard curve diagram, the detection limits of and were determined to be 1.34 × 10 and 1.56 × 10 M, respectively. Reaction of the probes with Hg resulted in a color change of the solution from colorless to pink. The corresponding molecular geometric configuration, orbital electron distribution, and orbital energy of these two compounds were predicted by density functional theory (DFT). The two probes and have been successfully used for imaging Hg in live breast cancer cells, thereby indicating their great potential for the micro-detection of Hg in vivo.