Study On Long Wavelength Fluorescent Sensors Based On Rhodamine Dyes

Rhodamine fluorophores have the advantages of high molar extinction coefficient,high quantum yield,good photo-stability and excellent water solubility.Therefore,they are widely used in the design and synthesis of various types of probes.The main designing idea of those probes is to adjust the fluorescence emission of the molecule by forming the conjugated system of the anthracene plane by introducing the amide ring.The introduction of an electron-donating group into the probe structure enables the excitation and emission wavelengths of a fluorophore to move towards long wavelength areas.The large number of rotatable bonds and the existence of C,N heteroatoms which insure the molecules have more thermal vibration rotation level to convert anti-Stokes luminescence.Therefore,the development of the excitation or emission spectrum in the long wavelength region,or anti-Stokes luminescence of fluorescent probe has become current research hotspot.In this paper,three kinds of organic molecule probes were designed and synthesized,and their fluorescence responses to the tested substances were studied.The main contents include:In the first section,we give a review and background introduction of this work,and the application of fluorescence sensors and long wavelength fluorophores based on different mechanisms in the field of supramolecular chemistry.In the second section,a fluorescence probe based on Rhodamine derivative was designed and characterized by UV and fluorescence spectroscopy.The probe can specifically identify the changes of pH in solutions and living samples.We also used cell imaging to achieve rapid monitoring of pH in cells.In the third section,two kinds of probes against metal ions were designed and synthesized,and their structures were confirmed by using nuclear magnetic resonance?NMR?and mass spectrometry.Their properties were characterized by UV and fluorescence spectroscopy.It was found that they were good selectivity towards Hg²⁺and Al³⁺respectively.