The Design,Synthesis And Application Of New Rhodamine-Based Fluorescent Probes

Toxic heavy metal ions accumulate through the food chain and are difficult to biodegrade.They are the primary source of biosphere pollution and lead to many physiological diseases.Therefore,accurate detection of heavy metal ions is of great significance.The fluorescent probe method has attracted much attention because of its faster detection and simpler operation than traditional detection methods.Rhodamine dyes are often used as scaffolds for biomarkers and fluorescence imaging because of their excellent photophysical properties,but their inherent small Stokes shift and ACQ effect greatly limit their further applications.In this thesis,three novel long-wavelength rhodamine-based fluorescent probes are synthesized based on the design of the classic rhodamine skeleton.The main contents include:1.We have designed and developed a novel large Stokes shift(67 nm),long wavelength(657 nm)fluorescent probe HZR based on rhodamine fluorophore,which can be used to detect Ag+and Hg2+in different solvents,with sensitivity Better and superior selectivity.The probe is based on the complex hydrolysis reaction between rhodamine hydrazide and ions.It can quickly(100 s)and efficiently detect silver ions in HEPES buffer solution.In addition,it can also achieve quantitative detection of silver ions in actual water samples.At the same time,the mercury ion in the PBS:EtOH=1:1 buffer solution shows very good specific detection,which further proves that changing different solvents can achieve different functional detection of the probe HZR.2.We have developed a new type of Rhodamine-Based fluorescent probe Hg664 with large Stokes displacement and near infrared emission for the specific detection of Hg2+ and MeHg+.Based on the desulfurization cyclization reaction induced by mercury ions,the probe can detect mercury ions and methylmercury ions with high sensitivity and selectivity,and the detection limit is as low as 1.87 ppb.In addition,the probe can quantitatively detect trace Hg2+ions in actual water samples,indicating that this method may be a potential method for detecting Hg2+ in environmental and biological systems.3.We have developed a novel Rhodamine-based fluorescent probe RT1 for the specific detection of Hg2+.The probe successfully realized the function of single molecule ratio meter,with good selectivity,high sensitivity and low detection limit.At the same time,this new type of rhodamine fluorophore has obvious AIE effect,which provides ideas for the further development of AIE-like rhodamine dyes.