Novel Fluorescent Probe toward Fe3+ Based on Rhodamine 6G Derivatives and Its Bioimaging in Adult Mice, Caenorhabditis elegans, and Plant Tissues

A new fluorescent probe LXY based on the rhodamine 6G platforms has been designed, synthesized, and characterized, which could recognize Fe3+ effectively in HEPES buffer (10 mM, pH = 7.4)/CH3CN (2:3, v/v). And the distinct color change and the rapid emergence of fluorescence emission at 550 nm achieved "naked eye" detection of Fe3+. The interaction mode between them was achieved by Job's plot, MS, SEM, and X-ray single-crystal diffraction. Importantly, the crystal structures proved that Fe3+ could induce the rhodamine moiety transform the closed-cycle form to the open-cycle form. But it is interesting that Fe3+ did not appear in the crystal structures. Meanwhile, the limit of detection (LOD) of LXY to Fe3+ was calculated to be 3.47 x 10(-9). In addition, the RGB experiment, test papers, and silica gel plates all indicated that the probe LXY could be used to distinguish Fe3+ quantitatively and qualitatively on-site. Moreover, the probe LXY has also been successfully applied to Fe3+ image in Caenorhabditis elegans, adult mice, and plant tissues. Thus, LXY was considered to have some potential for application in bioimaging.