The Designing,Synthesis And Application Of Several Kinds Of Small Molecular Fluorescent Probes

Organic small molecular fluorescent probes used to analyse target substrates is a new kind of instrumental analysis method.Due to advantages such as high sensitivity,broad concentration linear response to target molecules,good selectivity,convenient to operate,able to real time tracking analysis in vivo,little damage to biological bodies,it attracts more and more attention from scientists,and had been applied in many fields such as enviromental protection,water sample analysis,food quality analysis,medical diagnosis etc.In this thesis,three kind of fluorescent probes have been devised and synthesized to detect hydrogen sulfide,hydrogen bisulfite and hypochlorous acid,respectively,namely probe 1,probe 2,probe 3.The main content of the three chapters was narrated as follows:(1)In chapter two,a recovery type fluorescent probe,2-(2-(2,4-dinitrophenoxy)-3-methylphenyl)benzo[d]oxazole known as probe 1,based on the ESIPT theory,was synthesized,and the molecular structure of the probe was confirmed by ~1H-NMR spectrum.The 2,4-dinitrophenylether moiety in this probe structure is responsible for the hydrogen sulfide nucleorphilic reaction,and the corresponding fluorophore structure of probe 1 is recovered by the same time due to this nucleophilic reaction,so the ESIPT mechanism also recoverd along with a large Stokes shift,the background fluorescence interference was effectively avoided,and realized the purpose of high performance hydrogen sulfide detection.When applied in the analysis of hydrogen sulfide in real water sample,probe 1 achieved expected effect.(2)In chapter three,a new type of fluorescent probe based on the ICT mechanism,was devised and synthesized,4-(1-(4-methoxyphenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)benza ldeh-yde,namely probe 2,in order to detect bisulfite anion.And the molecular structure of probe 2 was characterized by ~1H-NMR spectrum.Phenanthroimidazole was chosen as the fluorophore,the aldehyde group was chosen as the reaction site.The bisulfite anion can attack the aldehyde group by nucleophilic reaction and block the ICT mechanism,so the fluorescent property of the nucleophilic reaction product is significantly changed compared to its probe.When applied in the analysis of bisulfite in real water sample,probe2 achieved expected results.(3)In chapter four,a novel recovery type fluorescent probe:1-(4-(4,5-diphenyl-1H-imidazol-2-yl)benzylidene)-2-(2,4-dinitrophe nyl)hydrazine,based on the ICT mechanism,was devised and synthesized to detect hypochlorous acid,namely probe 3.The hydrozone structure in this probe can specificly react with hypochlorous acid,and be turned into aldehyde group.The probe shows high sensitivity,high selectivity and broad linear concentration response toward hypochlorous acid.When applied in the analysis of hypochlorous acid in real water sample,probe 2achieved well agreement between the actual addition value and the experimental value.