The Synthesis And Properties Of Supramolecular Aie Fluorescent Materials Based On Acylhydrazone And Pillar[5]arene

In 2001,a novel class of luminophores exhibiting aggregation-induced emission?AIE?properties was discovered by Tang and coworkers.The number and variety of AIEgens are expanding very rapidly due to their colossal potential.In addition,pillararenes,a new kind of macrocyclic hosts,has attracted more attitions of researchers owning to their unique pillar shape,easy to functionalize and interesting host-guest properties.After summarizing the AIE-based supramolecular fluorescent meterials research work at home and abroad and combining the research of our team,this paper designed and synthesised several supramolecular AIE fluorescent materials based on??2-hydroxy?-naphthyl?methylene acylhydrazone and its functionalized pillar[5]arene,and further investigates their applications in detections and separations for ions or molecules.The paper will be divided into four parts to discuss the construction and performance of AIE fluorescent materials.In this chapter,we introduced the definition of Aggregation-Induced Emission?AIE?,and the constructions of AIE/AIEE fluorescence materials based on small molecular and pillar[5]arene,which were classified from the building blocks and applications.Meanwhile,we have summarized its applications in the detection of ions and molecules,light capture,drug delivery and smart materials,and proposed our research programme.In the second chapter,based on extensive research of acylhydrazones and their derivatives in ions recognition,in order to efficiently improve the detective sensitivity,we rationally introduce Aggregation-Induced Emission?AIE?into chemosensor,designed and synthesized a??2-hydroxy?-naphthyl?methylene acylhydrazone based AIE fluorescent chemosensor.Our strategies are as follows:firstly,in order to achieve the aggregation of the chemosensor,we rationally introduced multiple self-assemble driving forces,such as strong van der Waals force?through the long alkyl chain?,?-?stacking?through the aromatic groups?and multiple hydrogen bondings?through the acyl hydrazone group?.Secondly,naphthalene was employed as an efficient fluorogen for the purpose of producing strong AIE.Moreover,the acylhydrazone group was introduced as multi-guest recognition site.According to these rational designs,the obtained chemosensor DNS showed strong AIE in DMSO/H₂O?water fraction 80%?binary solution,which could serve as a novel AIEgen.In addition,a simple fluorescent sensor array based on the DNS has been developed.This sensor array could selectively sense Fe³⁺,Al³⁺,H₂PO₄^-in water solution.And this sensor array shows ultrasensitive detection for Fe³⁺,Al³⁺.The LODs of the sensor array for Fe³⁺,Al³⁺are in the range of3.54×10^-9 M to 9.42×10^-9 M.Moreover,it could realize the reversible detection of Fe³⁺and H₂PO₄^-in DMSO/H₂O?water fraction 80%?solution.Meanwhile,DNS-based test papers and thin films were prepared,which could serve as test kits for convenient detection Fe³⁺,Al³⁺in water.In addition,they could also act as efficient erasable fluorescent display materials.Based on the above research,this work provides a good design idea for the ultra-sensitive detection of multiple analytes.In the third chapter,since most supramolecular fluorescent materials can only detect ions but not effectively separate ions from water,in order to solve these problems,we still use??2-Hydroxy?-naphthyl?methylene acylhydrazone derivative DNS synthesized in the last part as our research object.And its gelation ability in mixed solvents,and its ion sensing and adsorption performance in gel state are further studied.The study suggested that the gelator DNS can self-assemble in DMSO/H₂O?8:2,v/v,wt%=3%?and form a stable supramolecular polymer gel?GDNS?,which also showed strong AIE.In addition,because the aggregation of DNS led to the detective signal amplifying,the AIE-based supramolecular polymer gel GDNS could ultrasensitively detect the heavy metal ions Hg²⁺,Cu²⁺,and Fe³⁺by signal amplification mechanism,and the lowest detection limits reach to 10^-11 M.In addition,the xerogel of GDNS also could adsorb and separate Hg²⁺,Cu²⁺,and Fe³⁺from aqueous solution with favourable adsorption property,and the adsorption rates range from 94.70%to 99.37%.Furthermore,the gel GDNS could act as a convenient test kit for Hg²⁺,Cu²⁺,and Fe³⁺as well as smart fluorescent display material.This provides a new method for the design of simple AIE supramolecular fluorescent materials with ultra-sensitive detection and effective separation performance.In the forth chapter,based on the above two works,in order to further improve the detection selectivity of the sensor,we introduced pillar[5]arene group in the design process,and designed and synthesized a??2-hydroxy?-naphthyl?methylene acylhydrazone functionalized pillar[5]arene?PNS?with double recognized sites.Herein,the pillar[5]arene group could not only act as?-?interactions sites,but also serve as the site to capture guest molecules;in addition,the naphthalene group could act as?-?interactions site and fluorescent signal group;moreover,the hydrazone group could serve as hydrogen-bond interaction site.Benefit from the above design,the sensor PNS exhibited superior performance for detecting L-Arg.The colorimetric and fluorometric limits of detection?LODs?for L-Arg are 0.6?M and 0.2?M,respectively.In addition,the sensing process of PNS for L-Arg showed high selectivity and the sensing mechanism was based on multiple surpramolecular interactions.Moreover,the sensor PNS could aggregate under the induction of L-Arg,and shown a favorable aggregation-induced emission enhancement?AIEE?phenomenon.Meanwhile,PNS-based test paper has been prepared,which could act as a convenient and efficient test kit to detect L-Arg in water.Hence,this work provides a new idea and method for the design of two-site recognition functional molecules and the highly sensitive and selective detection of amino acid.