Synthesis Of A Fluorescent Chemosensor Based On Carbazole And Isophthalic Acid Unit And Its Application In Metal Ions Detection

Fluorescent chemosensors refer to a kind of tool, which can change the fluorescent signal of the luminescent materials caused by the change of the surrounding environment and obtain the characteristic information of the surrounding environment.Because of the advantage of simple operation, highly sensitivity, fast response speed,detection of low cost and not affected by external magnetic field, the fluorescence chemosensor is widely used in environmental science, medical science, chemistry and biology, and other fields in recent years, especially in metal ion detection.The composition, mechanism of fluorescent chemosensor and the research progress of fluorescent chemosensors for Fe3+, Cr3+ and so on metal ions are reviewed in this paper. Carbazole molecule has relatively efficient charge transfer properties, and its derivatives have been extensively investigated for applications in electroluminescent devices and in fluorescent sensors for selective detection of metal ions due to their good hole transporting and luminescent properties. Isophthalic acid unit can coordinate with several transition metal ions, forming highly ordered coordination polymers. It is possible that when an isophthalic acid unit is linked to a carbazoly fluorophore forming a chemosensor, the change in electronic properties of the isophthalic acid unit due to coordination with metal ion may influence the photophysical states of the sensor, and it should lead to an observable change in the emission profile of the fluorescent probe. Herein, we reported the synthesis of an example of this kind of chemosensor and studied the selectivity of different metal ions by fluorescence spectrometry. The main research contents include:(1) A new fluorescent chemosensors, N-[4-(3,5-dicarboxylphenoxy)-butyl]-carbazole(1) was designed and synthesized, and its molecular structure was characterized by means of Fourier transform infrared spectroscopy(FT-IR), the proton nuclear magnetic resonance spectra(1H-NMR) and X-ray single-crystal diffraction.(2) By ultraviolet-visible absorption spectrum and fluorescence spectrum analysis method the optical properties of compound 1 and the selective recognition in ethanol/water(V/V = 1:1) solution for different metal ions were studied. It was found that the addition of Fe3+, Cr3+, Cu2+ and Pb2+ to the solutions of 1 caused marked fluorescence quenching, indicating the selectivities for Fe3+, Cr3+, Cu2+ and Pb2+ over other metal ions.(3) A new compound, N-[4-(Dimethyl-3,5-dicarboxylatephenoxy)-butyl]-3-nitrocarbazole(5), was obtained casually during studying the coordination of compound 1 with Fe, Cu, Zn and other metal ions. Its structure was characterized by X-ray single-crystal diffraction. The X-ray single-crystal diffraction data indicated that compound 5 crystallized in triclinic system, P-1 space group.