Synthesis And Application Of Anionic Fluorescent Probes Containing Heterocyclic Structure

Anions play an extremely important role in both nature and life.Therefore,it is of great significance to detect trace anions in environment and organism.Compared with cations,the development of anion recognition is relatively slow.Anions recognition still faces great challenges because of the properties of anions.This paper aims to design and synthese several anionic fluorescent probes by different methods,and apply to real samples analysis successfully.The main works are as follows:?a?An uncontrolled increase of nitrite concentration in groundwater,rivers and lakes is a growing threat to public health and environment.It is important to monitor the nitrite levels in water and clinical diagnosis.Herein,we developed a switch-off fluorescence probe?PyI?for the sensitive detection of nitrite ions in the aqueous media.This probe selectively recognizes nitrite ions through a distinct visual color change from colorless to pink with a detection limit of 0.1?M.This method has been successfully applied to the determination of nitrites in tap water,lake water and Yellow River water with recoveries in the range of 94.8%-105.4%.?b?As one of the most widespread anions,chloride ion largely existed in the water sources as well as living organism.Therefore,determination of chloride ions in biological samples is evidently important.Herein,we developed two analogous fluorescence probes BeQ1 and BeQ2for the sensitive detection of chloride ions.The chloride ions in biological samples were determined by a direct and simple method with the detection limit of 46 and 66?M respectively.In addition,the probes were found having the two-photon excitation property.?c?Phosphate ions are important nutrients in soil and indispensable anions in organism.Many fluorescence methods are applied to detect phosphate ions,but only a few anionic fluorescent probes designed by using aggregation-induced emission?AIE?.In this chapter,a fluorescent probe with aggregation-induced emission properties was designed and synthesed to detect phosphate ions.According to the interaction of phosphate ions with the probe TPAQ,the aggregation of molecules results in emission.With the advantages of good selectivity and high sensitivity,this probe has been applied to dectect phosphate ions in real samples successfully.It provides a new idea for the design of enhanced anionic fluorescent probes.?d?As the most abundant and significant anions in biosystem,pyrophosphate?PPi?and chloride ions?Cl^-?participate in many important physiological processes.Thus,design and synthesize a simple,sensitive,selective and long wavelength turn-on sensor for the detection and imaging of PPi and Cl^-in vitro and in vivo is very necessary.Herein,we have developed a simple porphyrin sensor 5,10,15,20-Tetrakis?4-hydroxyphenyl?porphyrin?THPP?with near infrared emission wavelength?657 nm?.When THPP react with Cu²⁺in low concentration,it quenched the fluorescence completely.PPi can coordinate with Cu²⁺and remove it from THPP,so the fluorescence of probe is recovered.Furthermore,THPP can be quenched by Ag⁺in high concentration,hence,the similar method to applied for detection of chloride ions under physiological condition with a detection limit of 17.3?M.Sensor THPP was applied to image PPi,and Cl^-in vitro and in vivo successfully.