Synthesis,Properties And AIE Activity Of Schiff Base Derivatives

Luminogens with feature of aggregation-induced emission?AIE?has received more and more attention.Its overcome the shortcomings of the traditional luminescence with emission quenching when they are aggregated.AIE molecules have been widely used in biological probes,fingerprint identification,chemical sensors and other fields.However,little work about the assembly,further disassembly process and its potential application of the AIE molecular are reported.This work design a series of salicylaldehyde azine derivative base on salicylaldehyde.The assembly and further disassembly process of the AIE molecular has been researched by multiple means.This paper mainly focuses on the experimental research contents:1.A series of schiff base compounds?1-8?based on the hydrazine hydrate are designed and synthesized.The structure was characterized by nuclear magnetic resonance spectra,mass spectrometry,infrared spectra and elemental analysis.Optical properties of the eight compounds were studied in the aggregation state and pure solvent,the result suggested that all the compounds are exihibited aggregation–induced emission?AIE?proprties.2.The aim of this work is to study the interaction of compound 1-3 with Cu²⁺ions by fluorescence spectrometry.Compound 1-3 are aggregation-induced emission?AIE?active compounds in pure aqueous solution with strong green emission,while the emission was selectively quenched to different extent in the presence of Cu²⁺ions.Detection limit for Cu²⁺is?200±23?nM?1?,?10±0.3?nM?2?and?100±25?nM?3?respectively.Mechanism investigation by dynamic light scattering?DLS?,ESI-MS,resonance light scattering spectra and EDTA competing analysis indicate that the presence of Cu²⁺induced the rearrangement of AIE?1?,AIE?2?,AIE?3?with the formation of a very tight self-assembly[1-Cu²⁺]_n,[2-Cu²⁺]_m or[3-Cu²⁺]_v particles.The AIE effect and Cu²⁺-induced self-assembly subsequently have been achieved in bioimaging with satisfactory results.3.Compound 8 is simply salicylaldehyde azine derivative base on the condensation of 5-chlorosalicylaldehyde with hydrazine hydrate.It shows a typical aggregation-induced emission enhancement?AIEE?activity with strong fluorescence in aqueous solution.The emission is selectively quenched severely in the presence of Cu²⁺ions.It was found that new assembly[8-Cu²⁺]_n are formed again.Moreover,depending on this reaction,energy changes??G?is estimated by Scatchard formula.Importantly,self-assembly[8-Cu²⁺]_n can be used to detect H₂S with fluorescence turn-on effect.These fluorescence changes were successfully observed in living cells.Highly efficient light-harvesting systems are successfully fabricated in aqueous solution based on AIE?8?.It is the first time to report the assembly and disassembly of AIEE and the according energy changes??G?though a simple Schiff base model compound.