Synthesis And Recognition Properties For HS0₃^-,H₂S,Al?3+?,Cu²⁺ Of Fluorescent Probe Based On 7-hydroxytetrahydroquinoxaline-6-carbaldehyde

Four types of fluorescence probes were designed and synthesized based on 1,4-diethyl-7-hydroxytetrahydroquinoxaline-6-formaldehyde?DHQC?,and realized recognition for HSO₃^-,H₂S,Al³⁺ and Cu²⁺.The recognition performance and applications of these fluorescent probes were studied in detail,and the main results are as follows:1.The fluorescent probe L1?a coumarin derivative? were synthesized by using DHQC as starting materials reacting successively with ethyl acetoacetate and 2,4-dihydroxybenzaldehyde.The probe L1 has non-fluorescence in the pure PBS buffer solution.When HSO₃^- was added into PBS buffer solution,the orange red fluorescence was produced and enhanced significantly,which indicated that the HSO₃^- could be selectively identified by probe L1.The probe L1 possess a maximum emission wavelength of 600 nm,a detection limit of 1.77×10^-7 mol/L and low cytotoxicity.It can be used for detection of HSO₃^-in mitochondria of living cells.2.The fluorescence probe L2 was obtained by using DHQC reacting successivelywithethylacetoacetate,p-hydroxybenzaldehyde and 2,4-dinitrobenzenesulfonyl chloride.The color of L2 changed from non-fluorescence to red fluorescence based on 2,4-dinitrobenzenesulfonic acid ester of L2 was cleaved by thiolysis of H₂S,and the precursor compound was released in the THF/Tris?1/1,v/v,pH=7.4? solution.The maximum emission wavelength of probe L2 is 650 nm,reaching the near infrared range.The detection limit of probe L2 is 3.91×10^-7 mol/L,because of low cytotoxicity of L2,it can be applied to live cells to detect H₂S.3.The fluorescence probe L3 was prepared by the reaction of DHQC with 1,5-naphthalene diamine.Probe L3 recognizes for Cu²⁺ with fluorescence "On-Off" responding in DMF/HEPES?1/1,v/v,pH=7.4?solution.Probe L3 possesses a maximum emission wavelength of 650 nm,which lie on the near-infrared range,a detection limit of 1.52×10^-6 mol/L and pH range of 5-12.In addition,probe L3 has low cytotoxicity and can be used for detecting Cu²⁺ in cells.4.The fluorescence probe L4 was synthesized by using DHQC and 3-hydroxyl-2-naphthohydrazide.Probe L4 recognizes for Al³⁺ with fluorescence"Off-On"responding in EtOH/Tris?1/1,v/v,pH=7.4? solution.The detection limit of L4 is 4.8×10^-4 mol/L,and the pH range is 4-6.Probe L4 has low cytotoxicity and can be used to detect Al³⁺ in cells.