Design,Synthesis,Photophysical Properties And Application Study Of Hexaarylbenzene-Based Fluorescent Probes

Fluorescent probe technology possesses several advantages,including rapid response,high sensitivity,high spatio-temporal resolution and easy operation,and thus has been widely used in the fields of analytical chemistry,biological and environmental science.It’s known that the reliability and responsiveness of this detection method mainly depend on the characteristics of fluorescent probes,hence the design and construction of fluorescent probes has attracted continuous attention.In this thesis,four hexaarylbenzene fluorescent probes were designed and synthesized by introducing electron donor（D）/receptor（A）groups to hexaarylbenzene skeletons.Meanwhile,their photophysical properties and applications in the detection of metal ions(Fe²⁺,Cd²⁺),trifluoroacetic acid and hydrazine hydrate were investigated.The main studies are as follows:（1）A D-π-A type fluorescent probe HAB-TP was designed and synthesized,with terpyridine（TP）as the electron acceptor and recognition unit,and methoxy group as the electron donor,respectively.HAB-TP exhibited AIE characteristics and a large Stokes shift,as well as a rare uphill type polarity-dependent fluorescence emission feature.It’s demonstrated that HAB-TP could be used as a probe for the naked-eye recognition of Fe²⁺.Moreover,HAB-TP displayed good sensitivity for Cd²⁺detection（fluorescence turn-off）with a binding ratio of 1:1,and the detection limit was 3.09×10^-7mol/L.In addition,the fluorescence of the probe could be restored after the addition of EDTA,indicating that the detection of Cd²⁺by HAB-TP was reversible.（2）Two hexaarylbenzene-based fluorescent probes HAB-DPA-1 and HAB-DPA-2containing a di（2-picolyl）amino（DAP）as the acid recognition group were designed and synthesized.Fluorescence titration experiments showed that the fluorescence intensity of HAB-DPA-1 and HAB-DPA-2 exhibited a distinct"turn-off"response to trifluoroacetic acid.The sensitivity of HAB-DPA-1 was higher than that of HAB-DPA-2 for trifluoroacetic acid,and their quenching constants were 0.074 and 0.021,respectively.（3）A hexaarylbenzene fluorescent probe HAB-NA of D-π-A type was designed and synthesized,with 1,8-naphthalic anhydride（NA）as the electron acceptor and hydrazine recognition unit,and methoxy group as the electron donor,respectively.This probe exhibited AIE characteristics,a large Stokes shift and a downhill type polarity-dependent fluorescence emission feature.The fluorescence titration experiments showed that HAB-NA could efficiently detect hydrazine hydrate（fluorescence turn-off）,with a detection limit of 6.98×10^-5M.In addition,HAB-NA can be made into test strips for easily and quickly detecting（gaseous）hydrazine in the environment.