Design, Synthesis And Properties Of Reactive Organic Fluorescence Sensor Based On Nitrogen Heterofused Rings

Hydrazine and fluoride are common environmental pollutants that can cause a variety of diseases.Compared with other methods,the use of organic small molecule fluorescence sensors to detect targets has the advantages of high sensitivity,high selectivity,convenience and cost-effectiveness.This paper aims to develop high sensitivity and high selectivity hydrazine and fluoride ion sensors with application value in organic-water mixed solvent systems.Based on the fluorescence characteristics of nitrogen-containing hetero-fused rings in the protonic polar solvents,several hydrazine and fluoride ion sensors were designed and synthesized.The performance of the fluorescence sensor was characterized and analyzed by experiments and quantitative calculations.The research results are as follows:?1?With hydrazine as the detection target,IM2 and IM3 based on ICT mechanism have good fluorescence performance and can effectively recognize hydrazine.However,the advanced excited state fluorescence of IM2 and IM3 interferes with the fluorescence signal of the recognition product.?2?IMYO was designed and synthesized as a ratio-type fluorescence sensor to detection of hydrazine.This sensor innovatively using the ynone group as the recognition group,and its fluorescence is effectively quenched by the carbonyl group in the recognition group.In addition,the double receiving site of IMYO and the hydrazine ring form a pyrazole,which effectively avoids the interference from active O,N and S.In IPA-Tris/HCl buffer?pH=7.4,1:1,v/v?,this sensor can be used to detect hydrazine with high sensitivity and selectivity.The detection range of hydrazine is wide?0.0⁰.35 mM,0-70 equv.?;the hydrazine detection limit is as low as 0.253 ppb;the response time is 30 min;and the fluorescence quantum yield of the hydrazine product can reach 21.5%.?3?IMPD was designed and synthesized as a ratio-type fluorescence sensor to detection of hydrazine.This sensor uses a maleimide group as the recognition group,and the two carbonyl groups in the recognition group effectively quench the fluorescence of this sensor.The difference in selectivity of the imide group to the hydrazine and the alkenyl group to the thiol in the recognition group is used to increase the selectivity of this sensor for hydrazine.In EtOH-Tris/HCl buffer?pH=7.4,1:1,v/v?,this sensor can be used to detect hydrazine with high sensitivity and high-selectivity.The hydrazine detection range is wide?0.0⁰.35 mM,0-175 equv?;the detection limit is as low as 9.156 ppb;the response time is 10 min;and the fluorescence quantum yield of the hydrazine product is as high as 39.7%.?4?IDS was designed and synthesized as a ratio-type fluorescence sensor to detection of fluoride.This sensor was designed by the mechanism of fluoride ion induced cyclization.In EtOH-HEPES buffer?pH=7.4,9:1,v/v?,this sensor is a high sensitivity and selectivity fluoride sensor with a fluorescence quantum yield of 23.13%.Apply real-time detection,fluoride concentration is in the range of 0-2?M;the fluorescence intensity of is linear with the fluoride ion concentration;the detection accuracy reaches 10^-7M level.