The Synthesis And Biological Applications Of Novel Fluorescent Probes Based On The Spirolactam-ring Of Rhodamine

On the development of molecular recognition,fluorescent probes have emerged in response to the needs of times as a novel mode.The fluorescent probes combined molecular recognition with fluorometric analysis and then expanded the applications.When reacted or bounded to acceptor specifically,the fluorophore of probe could express the recognition process in the form of optical signal.With the rapid development of interdisciplinary sciences,fluorescent probe technology is permeating to other subjects gradually.Under the circumstances,fluorescent probes should be more efficient and closer to biocompatibility.Excellent probes not only can be used in the external condition,the more important point was that they could be applied in the living biological system without obvious toxicity or side effects.Probes could detect the activity of the body,even be used in some major diseases detection and early treatments.The rhodamine framework is an ideal mode to construct fuorescent probes on account of its excellent photophysical properties.After reading a large number of literatures,we synthesized four kinds of novel "off-on" probes based on the spirolactam-ring of rhodamine（Ⅰa-d,Ⅱa-d,Ⅲa-c,IVa-c）,and discussed the recognition mechanisms for different acceptors.In addition,the toxicity,cell staining and labling of living organism were investigated,which showed satisfactory results.The main content of the paper included the following:（1）The fluorescent probes for Hg²⁺:synthesis,spectral properties and biological applications.Four probes（Ia-d）derived from rhodamine fluorophores were obtained.The spectral properties showed that probes displayed selectivity for Hg²⁺,and could be used for quantitative detection of Hg²⁺ with a detection limit of 0.16 μM.The recognition mechanism was investigated by DFT theoretical calculation.The probes could be applied in the fluorescence imaging of Hg²⁺ in film bases,L929 cells and mice.（2）The probes for dual monitoring of Fe³⁺ and CN-:synthesis,spectral properties and biological applications.Four probes（Ⅱa-d）were designed and characterized by X-ray crystallography based on rhodamine.The probes showed highly selective spectroscopic responses to Fe³⁺ over other metal ions.Further,the probes were used in the living cells and mice for detecting Fe³⁺ with excellent application value.Meanwhile,probe-Fe³⁺ complex could detect CN-quickly and quantificationally.The mode of "one-to-two" for constructing probes is novel and can save resources and improve work efficiency.（3）The probes for detecting of Pd²⁺:synthesis,spectral properties and biological applications.Three probes（Ⅲa-c）were synthesized based on rhodamine fluorophores and the structure of "N=C-C=C" served as receptor.Spectral properties showed that probes could form complexes with Pd²⁺ with the the stoichiometry of 2:1 and the detection limit was 0.19μM.The probes could be used as Pd²⁺ test strip,which provided a simple and convenient method for determination of Pd²⁺.The probes also can be applied in the fluorescence imaging of Pd²⁺ in cells and mice with low toxicity.（4）The probes for dual monitoring of Cu²⁺ and cysteine:synthesis,spectral properties and biological applications.Three probes（IVa-c）are designed based on rhodamine and azo derivatives.Spectral properties showed that probe IVa could serve as "naked-eye" probe for Cu²⁺ with a detection limit of 0.096 μM.The probes were successfully used for fluorescence imaging in living cells and mice with good cell permeability and biological compatibility.On the other hand,probe-Cu²⁺ complex could detect cysteine without the interference from homosysteine and glutathione,which provided an efficient way for the detection of cysteine.The whole recognition progress realized the selective and sensitive identification of two targets at the same time based on different mechanisms,which displayed high application value.