Research On Synthesis And Properties Of CN~- And Heavy Metal Ions Probes Based On Rhodamine B Acylhydrazone Derivatives

Anions and cations are closely related to people's lives,but excessive ions could cause serious problem to the human body and the environment.Among them,heavy metal ions and cyanide ions are more threatening to the human body,and those who are poisoned could lead to diseases and may cause death.Therefore,it is very important to study probe molecules with high sensitivity and high selectivity for detecting heavy metal ions and cyanide ions.In recent years,Rhodamine has attracted extensive attention due to its high fluorescence quantum yield,long excitation wavelength,good water solubility and low biotoxicity.Designing novel Rhodamine based fluorescent sensor is of great significance for identifying ions in aqueous solution in real life.In view of this,this paper designed and synthesized three kinds of Rhodamine B derivative sensor molecules that can recognize heavy metal ions or cyanide ions,and used spectral techniques to study their recognition performance.The paper is divided into the following four parts:Chapter?IntroductionIn this chapter,the research background,mechanism and significance of ion recognition,the recognition significance of heavy metal ions and cyanide ions were introduced.The research progress of Rhodamine probes and different kinds of rhodamine ion sensors was introduced in detail.Chapter?Synthesis and Research on recognitions and properties of Rhodamine B acylhydrazone derivative sensor Z to CN^-and its applicationIn this chapter,we designed and synthesized a novel high-selectivity chemosensor Z based on rhodamine B acylhydrazone derivatives,which showed both colorimetric and“turn-on”fluorescence responses for CN^-in aqueous solution.Results showed that after adding CN^-ion in aqueous solution,the chemosensor Z showed a significant color change that is visible to the naked eye from colorless to pale-yellow,and produced a strong green fluorescence rapidly.The Probe can distinguish CN^-by deprotonation and intramolecular charge transfer?ICT?mechanisms,as evidenced by ¹H-NMR titration and DFT calculations.In addition,the detection limit of the fluorescence response of the sensor to CN^-was 5.81×10^-8mol/L,which was measured by titration.The chemosensor Z has been successfully used to detect CN^-in sprouting potatoes.Z-containing test strips have also been prepared that can be used as colorimetric means for CN^-detection in potential applicationsChapter?Synthesis and Research on recognitions and properties of Rhodamine B acylhydrazone derivative sensor RD to CN^-and Cu²⁺and its applicationIn this chapter,we designed and synthesized a simple selective colorimetric and fluorimetric chemosensor RD based on Rhodamine B acylhydrazone derivative,which showed both colorimetric and fluorescence responses for cyanide and Cu²⁺in aqueous solution with specific selectivity and high sensitivity.In the presence of cyanide,the sensor exhibited a visible color change from colorless to pale yellow by naked–eyes and rapidly produced a strong yellow fluorescence in aqueous solution.The detection limit on fluorescence response of RD sensor to CN^-was down to 3.54×10^-7 mol/L.In addition,compared to other metal ions such as Fe³⁺,Co²⁺,Ni²⁺,Cd²⁺,Pb²⁺,Zn²⁺,Cr³⁺,Hg²⁺,Ag⁺,Ca²⁺and Mg²⁺in aqueous solutions,RD could show both colorimetric and fluorescence responses rapidly for Cu²⁺.Notably,this sensor could be used as a molecular switch controlled by CN^-and H⁺cyclically.Test strips based on RD were fabricated that could be used as a convenient and efficient CN^-and Cu²⁺test kits.RD could detect cyanide in germinated potato,bitter almond and tap water.Chapter?Synthesis and Research on recognitions and properties of Rhodamine B acylhydrazone derivative SD sensor to Hg²⁺and its applicationIn this chapter,we designed and synthesized a novel chemical sensor SD based on Rhodamine B acylhydrazone derivative,which displayed both colorimetric and“turn-on”fluorescence responses for Hg²⁺in DMSO/H₂O?1:9,v/v?solution.In the presence of mercury ions,the sensor SD showed an obvious change in color from colorless to distinct rose red by naked eyes and rapidly provided bright orange fluorescence under UV lamp in the aqueous solution.The detection limit on fluorescence response of SD to Hg²⁺was as low as 2.71×10^-7 mol/L.Compared to other metal ions such as Fe³⁺,Co²⁺,Ni²⁺,Cd²⁺,Pb²⁺,Zn²⁺,Cr³⁺,Cu²⁺,Ag⁺,Ca²⁺and Mg²⁺,SD could only selectively recognizes Hg²⁺.The results of the Job's plot and infrared spectra analysis suggested that the combined stoichiometry between SD and Hg²⁺was 1:1.Notably,SD could be used as molecular switch controlled by EDTA and Hg²⁺cyclically.In addition,SD-based test strips were produced which could be used as a convenient and efficient Hg²⁺test kits.SD also could qualitatively detect Hg²⁺in tap water.