New Fluorescent Probes Based On Rohdamine B Spirolactam

The study on fluorescenct probes has become a hotspot research in recent yearsfor their easy-operation, excellent selectivity and high sensitivity. They play a veryimportant role in many fields such as chemical, environmental sciences and medicinalscience.Rhodamine-based fluorescent probe have been widely used for the detection of the cationsowing to their excellent spectroscopic propertles such as relatively long emission wavelength,excellent water solubility, high fluorescence quantum yield and low cost. In this thesis, a seriesof novel fluorescent probes were synthesized to determine Al³⁺, citrate, and Hg²⁺,repectively. The contents of this thesis are presented as follows:Firstly, the synthesis of a novel fluoroionophore containing naphthalimide andrhodamine B and its application as a Al³⁺-sensitive ratiometric fluorescentchemosensor are described. The realization of ratiometric signaling is based on thereis an overlap between the excitation wavelength of rhodamine （energy receptor） andthe emission wavelength of naphthalimide （energy donor）. The detection limit of theprobe toward Al³⁺is1.0×10^-7M, with a linear performance in the concentration scopefrom5.0×10^-7to1.0×10^-5M. The rohdamine derivative exhibits excellent selectivityover other common metal ions，and pH independent in medium condition （pH6.0-8.0）．Secondly, we have synthesized a fluoroionophore based on rhodamine B, which isused to determine citrate in aqueous solution. With the experimental conditionsoptimized，the detection limit of the probe toward citrate is2.5×10-8M, with a linearperformance in the concentration scope from1.0×10^-7to5.0×10^-5M. The rohdaminederivative exhibits excellent selectivity over ther anions，and pH independent inmedium condition （pH6.0-8.0）．Finally, a rhodamine B-ethylenediamine containing2-quinolinecarboxaldehydehas been designed and synthesized as chemosensor for recognition of Hg²⁺. Thedetection limit of the probe toward silver ion is1.3×10^-7M, with a linear performancein the concentration scope from6.6×10^-7to2.4×10-4M. The experimental results showthat the response behavior of the fluorescence probe to Hg²⁺is pH-independent inmedium condition （pH5.0-9.0） with high selectivity for Hg²⁺over common cations.