Synthesis In Water And Applications Of New Fluorescent Probes In Recognition For Heavy Metal Cations

The exploration and application of green solvent or reaction media in various chemical processes,especially in synthetic procedures has been a focus topic in both academia and industrial research. In thisregard, reactions in neat water especially high selective reactions in aqueous phase have attracted more andmore attentions in synthetic chemistry, because water is one of the most abundant,cheapest andenvironmental benign solvent. Design and synthesis of fluorescent chemsensor have drawn much interestsin supramolecular chemistry in recent years due to its intrinsic distinct advantages in terms of highsensitivity, able to monitor substrate concentration in real-time and real-space and remote sensing In thelast few years, it is of great interest to develop some fluorescent probes which could recognize detect ionsin the aqueous solution and could be applied in biological cells.Under the guidance of the principles of green chemistry, The chemselective reductions of carbonylcompounds to alcohols in neat water using amine boranes as reductants have been studied in the thesis.Four series of new fluorescent probes based on1,4-dihydroxy-9,10-anthraquinonealdehydethiosemicarbazone,1,4-dihydroxy-9,10-anthraquinone acylhydrazones,8-hydroxyquinoline-7-aldehydethiosemicarbazide and8-hydroxyquinoline acylhydrazones derivatives were designed and synthesized inwater. The recognitions for heavy metal cations of new fluorescent sensors have been searched and somehighly sensitive and selective fluorescent chemosensor for the detection of Cu2+,Cd2+,Zn2+with a fast timeresponse in aqueous solution is demonstrated and an imaging study of Cu2+,Cd2+,Zn2+in living cells isalso successfully shown in this dissertation.This thesis mainly containing the following aspects:1,Chemoselective reduction of various carbonyl compounds to alcohols with ammonia borane (AB,MAB), nontoxic, environmentally benign, and easily handled reagents, in neat water was achieved inquantitative conversions and excellent isolated yields. Interestingly, α-and β-keto esters can be selectivelyreduced by amine borane reagent(AB,MAB) to corresponding hydroxyl esters in water with excellentyields, while diols are efficiently obtained using sodium borohydride as a reducing agent. The procedure is perfectly compatible with the presence of a variety of base-labile protecting groups, such as tosyl, acetyl,benzoyl, ester groups, and acid-labile protecting groups such as trityl and TBDMS groups, and theunsaturated double bond, nitro and cyano groups are intact in the process. A1-kg scale ction of methylbenzoylformate with AB was conducted in water and gave methyl mandelate in94%yield.The competitiveand intra-chemoselective experiments show that MAB effectively discriminates between aldehydes andketones.2,Seventeen1,4-dihydroxy-9,10-anthraquinonealdehyde thiosemicarbazones and fifteen1,4-dihydroxy-9,10-anthraquinone acylhydrazones were synthesized by the condensation of1,4-dihydroxy-9,10-anthraquinone-2-aldehyde and aryl or alkyl thiosemicarbazides or substitudedhydrazides for the first time. The reactions were completed in30min under the microwave radiation in neatwater with little amount of PEG-400as phase transfer catalyst and the products were obtained in excellentyields.The target products could be gotted by only simple filtration, washing and drying. The mainadvantages of this method are that reaction is quick, with excellent isolated yields, operation is simple,avoiding the use of poisonous organic solvents and acid, in line with the principles of green chemicalprinciple.3, Fifteen8-hydroxyquinolin-7-aldehyde thiosemicarbazones and fifteen acylhydrazones weresynthesized via the condensation of8-hydroxyquinolin-7-aldehyde and aryl or alkyl thiosemicarbazidesand substituded aryl hydrazides. The reactions were completed in15-30min under the microwave radiationin neat water with little amount of PEG-400as phase transfer catalyst and the products were obtained inexcellent yields.The products could be gotted by only simple filtration, washing and drying. Theadvantages of this method are that reaction is quick, excellent isolated yields, operation is simple, avoidingthe use of poisonous organic solvents and acid, in line with the principles of green chemical principle.4,The influence of various metal ions on the absorption and fluorescence spectra of some new sensorsbased on anthraquinone thiosemicarbazone compounds and anthraquinone hydrazide compounds(ESN1and EXZ2) were investigated in detail.Two fluorescent sensors ESN1and EXZ2were found to besensitive to the copper (II) ion in aquerous. In the investiganted15metal ions such asFe3+,Co2+,Ni2+,Cd2+,Zn2+,Hg2+,Ag+and Pb2+have little variations of the fluorescence, However, only Cu2+can lead to the fluorescence quenching in aqueous and PBS as the buffer solution in7.2pH. Therefore, ESN1and EXZ2were the favorable in cognition of Cu2+with high selectivity and sensitivity in aqueoussolution.1:.1binding stoichiometry was confirmed by the experimental results. In addition, biologicalimaging studies have demonstrated that ESN1and EXZ2can detect Cu2+in living kidney epithelialMDCK cells.5,The influence of various metal ions on the absorption and fluorescence spectra of some sensorsbased on8-hydroxyquothiosemicarbazone compounds and anthraquinone hydrazide compounds (KSN1andKXZ2) were investigated in detail.Two fluorescent sensors KSN1and KXZ2were found to be sensitive tothe Cd2+and Zn2+in aquerous. In the investiganted15metal ions such as Fe3+, Co2+, Ni2+, Hg2+, Ag+, Pb2+and so on, only Cd2+and Zn2+can lead to the fluorescence enhancement to7-10times in aqueous andHEPES as the buffer solution in7.0pH. Therefore, KSN1and KXZ2were the favorable in cognition ofCd2+with high selectivity and sensitivity in aqueous solution.1:.1binding stoichiometry was confirmed bythe experimental results. In addition, biological imaging studies have demonstrated that can detect Cu2+inliving kidney epithelial MDCK cells.and lung cancer H1299cells.In this thesis, the chemselected reduction of series carbonyl compounds in neat water, the one of themost abundant, cheapest, and environmentally benign sovent, with amine boranes were achieved inquantitative conversions and excellent yields. Some series of1,4-dihydroxy-9,10-anthraquinonealdehydeand1,4-dihydroxy-9,10-anthraquinonealdehyde derivatives were synthesized in water and their cognitionof heavy ions were investigated in detail. A few of highly sensitve and selective fluorescent probes forCu2+,Cd2+,Zn2+in aqueous solution is demonstrated.An imaging study of heavy ions in living cells isalso successing shown.