Synthesis Of Rare Earth Eu（Ⅲ）complexes And Heir Sensing Properties For N₂H₄ And H₂S

Human is a complex organism from the point of view of organic chemistry and biology.The whole life of human beings involves a variety of intricate biochemical reactions and signaling pathways.In order to maintain normal physiological functions of living organisms,we need to maintain and monitor the dynamic balance of biochemical substances,especially some anions and small molecules（such as N₂H₄,H₂S,etc.）,which often play a key role in these signaling pathways.Abnormal levels of these substances in the human body often lead to serious harm to human health.Studies have shown that overexposure to N₂H₄ can cause serious organ damage.In addition,the U.S.Environmental Protection Agency（EPA）classifies N₂H₄ as Hazardous Group B₂,a potential carcinogen.Many governments recommend a threshold limit（TLV）for N₂H₄ in drinking water as low as 10 PPB.Hydrogen sulfide（H₂S）is generated endogenous in the body through the sequential reaction of cysteine and homocysteine in the presence of enzyme catalysts.Some international research groups have proved that the concentration of hydrogen sulfide is related to diseases such as Down’s syndrome,Alzheimer’s disease and liver cirrhosis,type 4 diabetes.H₂S also plays an important role in neurotransmission,vasodilation and apoptosis as a gas regulator.Therefore,it is very important to develop efficient,rapid and sensitive fluorescent probes for monitoring the concentration of N₂H₄ and H₂S.Rare earth complexes have been widely studied due to their low toxicity,long life and large Stokes displacement,and have been developed into new luminescent probes and shown excellent prospects for biomedical applications.However,rare earth Eu（III）complex fluorescent probes can rapidly analyze analytes in biological systems through fluorescence imaging,and even produce almost no damage to biological samples.Based on this,I proposed my own research direction to construct a novel Eu（III）complex fluorescent probe,and to study the sensing properties of N₂H₄ and H₂S,such as selective recognition,anti-interference,quantum yield,fluorescence performance,etc.The main research contents of this paper are as follows:In chapter one,the introduction mainly introduced the overview of N₂H₄,H₂S fluorescence sensor and the application of rare earth complex in fluorescence sensor.On this basis,the main research contents of this subject were put forward.In chapter two,we synthesized ligands tymp and Hppa through Schiff base reaction and condensation reaction,and designed and synthesized fluorescent probe Eu（tymp）₂Hppa for the detection of N₂H₄ with colorimetric and ratiometric using ester group as recognition site.Through a series of experiments,it was proved that the probe Eu（tymp）₂Hppa had good anti-interference ability and good selectivity for N₂H₄recognition.All these experiments proved that Eu（tymp）₂Hppa could detect N₂H₄rapidly,sensitively and selectively.In addition,it had application value to the detection of actual water sample N₂H₄.In chapter three,we first synthesized the ligands tdl and abp by krohnke pyridine reaction and nucleophilic substitution,respectively.Using azide group as recognition site to recognize H₂S,Eu（tdl）₂abp for colorimetric and fluorescence detection of H₂S was designed and synthesized.A series of experiments showed that Eu（tdl）₂abp probe had excellent anti-interference ability and high selectivity for H₂S recognition;These experiments showed that Eu（tdl）₂abp can detect H₂S quickly,with high sensitivity,selectivity and quantification.In addition,it was preliminarily proved that the fluorescent sensor could be applied to the detection of H₂S in actual water samples based on cell imaging.In chapter four,we synthesized 1 through condensation reaction,then synthesized ligand abt through substitution reaction,and also recognized H₂S with azide group as recognition site.By changing the auxiliary ligand,we designed and synthesized a red light probe Eu（ttbd）₃abt,which could be used to detect H₂S.Through a series of experiments,it was proved that the probe had excellent anti-interference ability and selective recognition of H₂S.These experiments proved that Eu（ttbd）₃abt can detect H₂S rapidly,selectively and quantitatively with high sensitivity.