Design, Synthesis And Ion Recognition Performance Of Novel Aniline And BAPTA Receptor Fluorescent Probes

Among the various techniques to detect metal ions,small-molecule fluorescent probes have received much attention.Through mechanisms most commonly as PET,ICT and FRET,small-molecule fluorescent probes can convert the ion recognition to tangible fluorescent signals and thus exhibit lots of advantages and characteristics,such as instant response,high selectivity,low detection limit,linear response and visual detection process.Zinc,copper and related d-block metals are emerging as significant players in both neurophysiology and neuropathology.Zinc is the second most abundant transition metal in the body with highest concentration occurring in the brain,and copper is the third most abundant.However,as implicated in a number of neurodegenerative diseases,abnormal accumulation and disruption of copper will trigger uncontrolled oxidation-reduction chemistry.Moreover,copper and mercury are widely distributed in the air,water and soil,excessive distribution of copper and mercury will threaten ecological environment and human health.As a consequence,Cu2+/Hg2+/Zn2+-indicating fluorescent probes,which can provide critical information for their assessments,are widely used and still in high demand.Novel design and optimization of receptors and fluorophores in small-molecule fluorescent probes are always accompanied by significant change of probes' performance.In this dissertation,probes are designed based on Intramolecular Charge Transfer(ICT),and electron-donating/electron-withdrawing groups were introduced to receptors and fluorophores,resulting in a novel group of Cu2+/Hg2+/Zn2+ probes with response in fluorescence.Furthermore,ion recognition of probes,influence of metal ions' concentration on fluorescence spectra of probes,complexation stoichiometry of probes and metal ions were studied and discussed.Based on above mentioned,the research work can be divided into three main parts:1.Novel fluorescent probes S1?S10 were designed and synthesized by incorporating benzimidazole as the fluorophore and phenylamide receptor.In the receptors,two,three and four recognition sites were introduced to explore actual polyamide-metal ions interactions.And in fluorophores,electron-donating and electron-withdrawing groups were introduced to alter fluorescence properties and affinity to metal ions of probes.The fluorescence absorption and emission spectra of S1?S5 were reported.2.Novel fluorescent probes S11?S17 were designed and synthesized by incorporating benzimidazole as the fluorophore and BAPTA receptor.Electron-donating group-CH3 and electron-withdrawing-F were introduced to the benzene rings of BAPTA to alter its affinity to metal ions.And-NO2 and-CH3 were introduced to fluorophores to change the fluorescence properties.The fluorescence absorption and emission spectra of S11,S13 and S14 were reported.3.Methyl acetate probes S1?S5,S11,S13 and S14 were hydrolyzed to obtain corresponding Cs salts T1?73,T11,T13 and T14,and the eight Cs salts were applied to ion recognition.Among them,T2,T4,T11,T13 and T14 showed fluorescence response to Cu2+,Hg2+ and Zn2+,and influence of metal ions' concentration on fluorescence spectra of probes was analyzed.Also,the concentration ranges of metal ions with probes' linear response were gotten.Finally,Job's plots were used to investigate the complexation stoichiometry of probes and metal ions.