Synthesis Of Novel Phthalimide-Based Dyes And Its Application In Mercury And Palladium Ions Detection

Mercury and palladium are not biodegradable and hence could be concentrated through the food chain.Excess mercury or palladium accumulation may induce heavy damage to the central nervous system.Whereas standard techniques often require expensive instrumentation and/or complicated sample preparation.Small fluorescent probes are becoming popular because of their ease of application in solution as well as their high sensitivity to and selectivity for trace analytes with spatial and temporal resolution.3-Aminophthalimide（API）has been reported as an important fluorophore exhibiting a large Stokes shift upon excitation by excited state intramolecular proton transfer（ESIPT）.Furthermore,the fluorophore also possesses other favorable properties such as relatively high fluorescent quantum,good photostability,and facile preparation.In this work,three new phthalimide-based fluorescent probes for the detection of mercury and palladium ions have been designed and developed respectively.Furthermore,several API-based fluorescent dyes have also been designed and synthesized.1.A new 3-aminophthalimide-based fluorescent probe for the detection of Hg²⁺has been rationally designed and developed.The probe operates via the specific mercury-promoted desulfurization reaction of thiophthalimide to phthalimide and exhibits high selectivity and sensitivity in an almost pure aqueous solution with a low detection limit of 1.5 ppb.Furthermore,the probe was successfully used for the fluorescence imaging of Hg²⁺in live cells.2.A new 3-hydroxyphthalimide-based fluorescent probe for the ratiometric detection of Hg²⁺has been rationally designed and developed.The probe operates via the specific mercury-promoted hydrolysis reaction of allyl group and exhibits high selectivity and sensitivity in an almost pure aqueous solution with a low detection limit.Moreover,the probe could be used in the different water samples for the quantitative detection of mercury ions.3.A new ESIPT-based water-soluble fluorescent chemodosimeter for the ratiometric detection of palladium ions has been rationally designed and developed.Based on the specific reactivity of palladium-promoted hydrolysis,the probe exhibited a high selectivity and sensitivity for palladium ions.Furthermore,the probe was successfully used for fluorescence imaging of Pd²⁺in living cells.4.Several novel API-based fluorescent dyes have been designed and synthesized by using3-chlorophthalic anhydride as starting material.The UV-vis and fluorescent spectra of all of those dyes have been carefully studied.This kind of dyes exhibiting small molecular weight,good solubility,tunable fluorescent emission,and high quantum yield,and could be used as excellent fluorophores for chemical and biological applications.