Design,Synthesis And Properties Of AIE Stimulus-Responsive Dyes

Aggregate-induced luminescence(AIE)materials overcome the adverse effects of the aggregation-induced fluorescence quenching(ACQ)effect in practical applications,making them have important application value in the fields of fluorescence sensors,biological imaging,circular polarization luminescence,and electroluminescence.Among them,stimulus-responsive materials can change their light-emitting characteristics with changes in the external environment(such as light,heat,force,p H,etc.),and have the advantages of sensitive response and reversible fluorescence changes,which have attracted the attention of researchers.The purpose of this article is to study organic fluorescent materials that can exhibit reversible fluorescence changes under the stimulation of force,heat,light,and solvents.The main contents are as follows:Chapter 1:The mechanism,type and application of aggregation-induced luminescence are reviewed.The luminescence mechanism and the types of stimulus response of AIE materials are introduced.Chapter 2:In this chapter,two phenanthrenequinone hydrazones PHPO and NHPO are designed.Both compounds exhibit AIE effects.Unlike PHPO,the fluorescence of NHPO is almost completely quenched at f_w of 99%.NHPO has a largerπ-conjugated system,which may be more inclined to form amorphous aggregates,leading to a decrease in fluorescence intensity;and particle size measurements confirm this assumption.At the same time,we have grown single crystals of NHPO and proved its AIE mechanism.In addition,we found that both compounds responded to mechanical forces:the initial powder obtained by column chromatography was crystalline and showed strong fluorescence emission;but after grinding in a mortar,the fluorescence intensity of the two compounds gradually weakened Until it disappears completely,the fluorescence can be restored by heating(or dichloromethane steam)to achieve the purpose of reversibly adjusting the fluorescence.At the same time,the mechanism of the force-induced color change is discussed in combination with the characterization and theoretical calculation of materials during the force-induced color change.Chapter 3:In this chapter,two borofluoro compounds with stronger fluorescence efficiency were synthesized by introducing borofluoro groups on the basis of PHPO and NHPO.We have cultivated the crystals of NHPO-BF2.According to their photophysical properties and X-ray single crystal structure analysis,their AIE properties are attributed to the formation of H(J)aggregates,which is formed by multiple intermolecular interactions to limit the solid state.Intramolecular motion.In addition,we found that these two compounds have mechanical discoloration properties.The solid powder of the two compounds obtained by column chromatography emits intense red fluorescence.After grinding,the red fluorescence is almost completely quenched.The fluorescence can be restored by recrystallization and methanol steam fumigation.After XRD testing,it was found that the solid after grinding changed from crystalline to amorphous,and then returned to crystalline after recrystallization.Chapter 4:In this chapter,two cyanine-like dyes and three diarylvinyl compounds were designed and synthesized.We combine a fluorescent chromophore with a diarylene unit and hope to synthesize a series of photochromic compounds with better light emitting properties.Tests show that only DTE-P has good photochromic properties,and although DTE-Q has photochromic properties,it cannot achieve a reversible cycle,and Pyr-DTE does not have photochromic properties.In order to conveniently obtain the single crystal structure to study its intermolecular interactions,Pyr-S and Pyr-C were also synthesized;we found that both compounds have AIE and force-chromic properties.Pyr-S and Pyr-C form aggregates in poor solvents,resulting in enhanced fluorescence,but as the aggregation effect increases,the fluorescence will quench;under the grinding of mechanical force,the fluorescence can be completely quenched,but in methane vapor Restore fluorescence.Chapter 5:The thesis summary and main conclusions.In this thesis,9 compounds were synthesized and studied,and 6 compounds with force discoloration and 2 compounds with photochromic effect were obtained.