Syntheses And Application Of Novel 1,2,4-triazolpyrimidines Fe³⁺ Fluorescent Probes

Iron,especially Fe³⁺ions,is one of the most important trace elements in organisms.It is very important to develop Fe³⁺ions fluorescent probes with low detection limit,high specificity and rapid response.Based on the novel 1,2,4-triazo pyrimidine compounds which are self-discovered and have emission fluorescence properties and specific response to trivalent iron ions,we designed and synthesized a new class of 1,2,4-triazo pyrimidine compounds Fe³⁺ions fluorescent molecular probes.The following work has been completed:A class of 1,2,4-triazo pyrimidine compounds was designed by transforming?2,5,7?different aromatic rings to change their conjugation effect and planar rigidity.12 novel 1,2,4-triazo pyrimidine compounds were synthesized by amide,cyclization,condensation cyclization,bromination,coupling,reduction,substitution and so on using acyl chloride and aminoguanidine bicarbonate as the raw materials.The results showed that the fluorescence wavelength of 7 compounds?7 a?7b?7c?8a?8b?8d?8g??450 nm,and the fluorescence intensity of compound 8a was strong.Among them,the 8a with the strongest fluorescence intensity had specific selectivity and extremely high sensitivity to Fe³⁺ions and was not disturbed by other ions,especially divalent iron ions.Compound 8a stable fluorescence spectra in the pH=3.0-8.0,so it can be used for testing under pH=7.4 physiological conditions.Fe³⁺ions can quench the fluorescent molecular probe 8a,and respond quickly?<5 s?,but after adding OH^-to the probe determination system after quenching,the fluorescence recovers,so the fluorescent probe has cyclic reversibility;the detection limit of the fluorescent molecular probe 8a can reach 0.82?M.For Fe³⁺ions detection density functional theory?DFT?is used to calculate the UV absorption wavelength and fluorescence emission wavelength of 12 compounds in this paper.It is found that the calculated results are basically consistent with the actual test results.The accuracy of the calculation method provides a basis for further directional design of such fluorescent molecules with specific emission wavelengths.The fluorescent molecular probe 8a made into fluorescent test paper can achieve rapid identification of Fe³⁺ions.Fluorescent molecular probe 8a has low cytotoxicity and can pass through the cell membrane into the cell,which can be used for the detection of Fe³⁺ions in the cell.The fluorescent molecular probe 8a was successfully applied to the detection of Fe³⁺ions in spinach,and the Fe³⁺content of spinach was about 5.35 mg/kg,This is the first time to measure the content of spinach,and other existing methods can only measure the total iron content?8.94 mg/kg?.The successful application of this fluorescent probe in the detection of spinach Fe³⁺ions lays the foundation for its accurate detection of Fe³⁺ions content in other animals and plants.The results of this paper provide some references for the study and application of1,2,4-triazo pyrimidine structures in the field of spectroscopy and Fe³⁺ions fluorescent molecular probes.