Synthesis And Performance Studies Of Reactive Fluorescent Probes Based On Benzothiazole Derivatives

Benzothiazole and its derivatives are an important class of heterocyclic compounds.The structure of these compounds can be modified reasonably,and specific reactive recognition groups can be introduced,which can be used to construct fluorescent probes of benzothiazole derivatives.In this paper,a series of fluorescent dyes were synthesized based on 2-（2′-hydroxyphenyl）benzothiazole,and fluorescent probes were further synthesized,and the recognition properties of the probes were investigated.The results are as follows:1.Synthesis and properties of probes HBTN-Y and HBTY-H based on AIE mechanismAn AIE-active fluorescent dyes HBTN was synthesized and its AIE properties were investigated.On this basis,the probe HBTN-Y was synthesized,which can specifically recognize cysteine in Me CN/H₂O（1/1,v/v,PBS 20 m M,p H=8.4）solution,and the reaction releases of HBTN.HBTN has the dual nature of"AIE+ESIPT".The exhibits a large Stokes shift（263 nm）and long emission wavelength（637 nm）.The probe has good anti-interference ability,low detection limit(6.51×10^-6M),suitable for neutral and weak alkaline p H range（7～9）,and has been successfully applied to cell imaging.A fluorescent probe HBTY-H was synthesized.The probe has a faster response time（15 min）to N₂H₄in Me CN/H₂O（3/7,v/v,HEPES 10 m M,p H=7.4）solution,and the reaction releases the AIE-active fluorescent dyes HBTY,which has a higher Fluorescence quantum efficiency.The probe has a low detection limit(1.56×10^-6M),a wide p H range（7～10）and is used for the detection of N₂H₄in actual water samples.2.Synthesis and properties of fluorescent probes HBTM-Pd and HBTM-Hg based on ICT mechanismA fluorescent probe HBTM-Pd was synthesized.The probe recognizes Pd⁰by the Tsuji-Trost reaction mechanism,and the reaction mechanism is verified by HRMS and ¹H NMR.The probe HBTM-Pd has good selectivity and anti-interference ability in THF/H₂O（4/6,v/v,Tris 10 m M,p H=6.8）solution,and the reaction releases HBTM.HBTM has the dual nature of"ESIPT+ICT",exhibits a large Stokes（203 nm）shift and high fluorescence quantum efficiency.The probe has a fast response time（5 min）for identifying Pd⁰,the detection limit is(1.67×10^-7M),and the applicable p H range is wide（3～8）.The probe can detect Pd⁰on the test strips.A fluorescent probe HBTM-Hg was synthesized.The probe can specifically recognize Hg²⁺has good selectivity and anti-interference ability when using sodium chloride to mask Ag⁺in DMSO/H₂O（5/5,v/v,HEPES10 m M,p H=7.4）solution,the probe has a fast response time（25 min）to Hg²⁺,with a detection limit of(2.14×10^-6M)and a near-neutral p H（7-8）application range.The probe HBTM-Hg has good detection of Hg²⁺in real water samples and has been successfully applied in MCF-7 cells.