Study On Synthesis,Characterization And Properties Of Metal Cation Fluorescent Probes Based On Rhodamine

Metal cations are widely found in nature and organisms.Some of them play important roles in protecting the ecological environment,maintaining the balance of living systems,and as indicators of disease prediction.Cation detection has become very important in the fields of chemistry,environmental science,biology,clinical diagnosis.The detection of metal ions by the fluorescent probe has the advantages of high sensitivity,good selectivity,real-time losslessness,and simple operation.It has a very wide range of application prospects and has become the current mainstream method for detecting metal ions.Therefore,this paper has synthesized three novel rhodamine fluorescent molecular probes.UV-vis absorption spectroscopy,fluorescence emission spectroscopy,¹H NMR,EMI-MS and density functional theory calculations were used to analyze the probe's response to metal ions.?1?A rhodamine derivative RC1 was synthesised via the hydrazone forma--tion of rhodamine 6G hydrazide with 7-diethylamino-3-?1-hydroxy-3-oxobut-1-enyl?-2H-chromen-2-one.As a colourimetric and ratiometric fluorescent probe,the derivative exhibited high selectivity towards Cu²⁺in neutral aqueous media.The detection limit of RC3 for Pd²⁺is 0.17?M.The probe sensed Hg²⁺with fluorescence enhancement at pH=10.The limit of detection for Hg²⁺was 2.96?M.To validate the applicability of the probe,the probe was used to detect Cu²⁺and Hg²⁺ions in actual water samples.The application of the fluorescent sensor in monitoring intracellular Cu²⁺in Hela cells has also been demonstrat--ed.?2?A rhodamine hydrazone RC2 bearing coumarin moiety has been designed and prepared,which exhibits high selectivity toward Co²⁺and trivalent metal ions with fluorescence enhancement in CH₃OH solution.However,RC2 selectively responses to Al³⁺in almost pure H₂O media.Moreover,RC2 could also act as a colorimetric probe to Cu²⁺in either CH₃OH or aqueous solution.The limit of detection of Cu²⁺by probe RC2 is 86.8 nM.In addition,sensor RC2 displays the aggregation induced ratiometric emission?AIRE?activities,which were investigated in mixed H₂O/CH₃OH solution.?3?A ratiometric fluorescent chemosensor RC3 with high sensitivity and selectivity for Pd²⁺ions based on a conjugate of indole and rhodamine B has been developed.The binding process was confirmed by UV-vis,fluorescence,mass spectroscopy,¹H NMR,and DFT calculation.The detection limit of RC3 for Pd²⁺is0.17?M.The as-synthesized probe was successfully applied in monitoring Pd²⁺in living cells.