Synthesis And Properties Of A Novel Rhodamine Class D "OFF - ON" Type Fe ^{3 +} Fluorescence Probe

Iron is an essential metal elements in biological system and plays a vital role in many biochemical processes. It is not only involved in the synthesis of hemoglobin, myoglobin and various metal protease, but also as a cofactor in the cell metabolism participate in many enzyme reactions and transport the oxygen in hemo. Both its deficiency and overdose can induce serious body function disorders which further cause some diseases, such as small-cell anemia, liver damage, kidney and heart failure, etc.. Therefore, the development of analytical method for the selective and sensitive detection of Fe3+ in biological inside and outside and environment has been a very important research topic.In terms of methods for detecting Fe3+, as fluorescence analysis with high specificity, controllable switch, easy operation, rapid analysis and has small damage and poison for cells, so it has arisen the great attention of people. In this paper, we designed and synthesized 6 kinds of Fe3+ fluorescent probes R1-R6 based on rhodamine B spirolactam-ring "OFF-ON " mechanism. The main contents of this paper include:1. With the rhodamine spirolactam-ring leuco system as a template,6 new kinds of rhodamine-based "OFF-ON" fluorescent probes R1-R6 were designed and synthesized by amide bond bridging rhodamine B fluorescence matrix and the other recognition group which containing N, O, S heteroatom. Probes’chemical structure were characterized and confirmed by HRMS-ESI, IR,1H NMR,13C NMR techniques and the crystal structure of Rl, R4, R5 were also determined. In addition, the ratio between the reactants on the influence of the target product yields were investigated.2. The recognition behavior of the probes R1-R6 were researched. The UV and fluorescence spectra of probes R1-R6 for the common alkali metal, alkaline earth metal, heavy metal and transition metal ions were studied, the results found that probes R1-R6 have a good selective recognition ability for Fe3+(the probe R6 was slightly interfered by Cu2+). In addition, the titration of fluorescence and UV-visible of probe compounds, Job’s Plot complex curve, reversibility and the influence of pH stability research experiments showed that the synthesized probes R1-R6 are based on rhodamine B "OFF-ON" recognition mechanism of Fe+ fluorescence enhancement probe, and have potential applications.3. As an extension of the theory, the cytotoxicity of the probes R1-R6 was tested by MTT, and further the probes R1-R6 have been applied to indentify Fe3+ in rat nerve cells(PC12) biological cells imaging experiment under confocal laser scanning microscope. The result showed that the probe R1-R6 has the advantages of less toxicity, good cell penetrability and very excellent anti-interference ability, can be used to detect and image Fe3+ in living cells, which has potential application in biological detection.