Synthesis Of Non-aromatic Ammonium Salt And Amide Molecules And Their Fluorescence Properties

Aggregation dependence is a common characteristic of fluorophores,including the phenomenon of Aggregation Induced Fluorescence Quenching(ACQ)of classical conjugated fluorescent substances and Aggregation Induced Emission(AIE)of non-aromatic organic fluorescent substances.Non-aromatic organic fluorescent substances with AIE phenomenon usually contain amino group,carboxyl group,hydroxyl group,amide group and other groups that constitute amino acids,polypeptides,proteins and other molecules,so they have excellent water solubility,good biocompatibility and low toxicity.Using non-aromatic polycarboxylic acid and polyamine molecules as raw materials,non-aromatic ammonium salt,fluorescent chiral amide molecule,carbon dot and composite materials assembled by carbon dot were prepared by low-temperature neutralization reaction and hydrothermal method,respectively.Through a series of characterization,the structure and fluorescence properties of non-aromatic fluorescent molecules were analyzed,and the relationship between the structure and fluorescence properties was explored,and it was applied in the fields of ion detection and heme detection.The specific research contents of this paper are as follows:1.Four non-aromatic ammonium salts,EA-EDA,CA-EDA,EA-DEA and CA-DEA,were prepared by low-temperature neutralization reaction using glycolic acid(EA),citric acid(CA),ethylenediamine(EDA)and diethylenediamine(DEA)as raw materials.The successful synthesis of non-aromatic ammonium salt was proved by structural characterization and the optical properties show that the emission center is a space electron delocalization system composed of molecular clusters.At the same time,the cluster will restrict the movement of the molecular chain,so that the fluorescence emission is further enhanced.These four non-aromatic ammonium salts have obvious concentration dependence,and the increase of viscosity in concentrated solution,solid-state and solvent will significantly enhance the fluorescence emission,showing typical AIE characteristics.In addition,the high water-solubility and biocompatibility of this nonaromatic ammonium salt indicate its potential application in the field of fluorescent biological probes.2.In this part,a series of preparation conditions were explored using chiral L-cysteine(L-Cys)and aminopropyl triethoxysilane(APTES)as raw materials,and the fluorescent chiral amide molecule CYS-APTES were successfully prepared.CYS-APTES has good water solubility,stable spherical structure,unique green fluorescence emission and obvious chiral characteristics.As a sensor for the detection of heme with chiral structure,CYS-APTES has demonstrated excellent specificity and low detection limit(29.5 nM)for heme and has been successfully applied to the detection of human serum samples,which has the potential for application in the field of cell biology and environmental science.3.Carbon point EDTA-AEAPMDS with AIE properties was synthesized by hydrothermal method from ethylenediaminetetraacetic acid(EDTA)and aminoethyl aminopropyl methyl dimethoxy silane(AEAPMDS)and was applied to ion detection.The fluorescence intensity of carbon dot EDTA-AEAPMDS increases linearly with the concentration at low concentration,and it has the property of solid luminescence.Non-aromatic EDTA-AEAPMDS/epoxy resin composites were prepared by doping EDTA-AEAPMDS into epoxy resin,which showed more excellent fluorescence stability.In addition,the prepared EDTA-AEAPMDS can be used for qualitative and quantitative detection of Cu²⁺and Cl O^-,with strong anti-interference ability,excellent selectivity and relatively high sensitivity.In conclusion,the research content of this paper provides an effective way for the synthesis of non-aromatic fluorescent molecules,especially for the preparation of chiral nonaromatic fluorescent molecules,and enriches the synthesis methods of this kind of fluorescent molecule.It has certain reference value for further clarifying the fluorescence principle of non-aromatic molecules and developing their potential application fields.