Synthesis And Recognition Properties Of New Fluorescent Probe Based On Rhodamine

The recognition and sensing of biologically and environmentally important species has emerged as a significant goal in the field of chemical sensors in recent years. Among the various analytical methods, fluorogenic methods in conjunction with suitable probes are perferable approaches for the measurement of these analytes because fluorimetry is rapidly performed, nondestructive, highly sensitive, sutiable for high-throughput screening applications, and can afford real information on the localization and quantity of the targets of interest.As a fluorophore and chromophore probe, the rhodamine fluorochrome has attracted considerable interst from chemists on account of its excellent photophysical properties such as long absorption and emission wavelength, high molar extinction coefficient and high fluorescent quantum yield and so on.The following are the main content of this dissertation.In the part of review, several related issues of fluorescence were introduced, including the basic concept of fluorescence, species of fluorophores, the detection mechanism and its development of fluorescent probe.Several fluorescent probe based on rhodamine-lactam were designed and synthesized, and their sturctures were confirmed by 1H NMR and 13C NMR, as well as studied its fluorescence and UV spectrum.The compound 2-1 could used as a nake-eye fluorescent probe, which could detect Fe3+in CH3CN, showing the strong emission at 580 nm. Based on B-H plot the 1:1 binding mode was proposed, and the detection limit was measured to be 5.18 ×10-7mol/L(S/N≥3).Fe3+could be recognized by compound 2-2 in CH3CN with the detection limit of 1.97 x 10-8 mol/L (S/N> 3). More importantly, the 2-2- Fe3+ complex could be used as reversible fluorescent probe to recognize F-.A novel rhodamine 6G-based sensor 2-4 was synthesized, which exhibited a high selectivity for H2PO4- in the presence of many other anions in a CH3CN/H2O (5/5, v/v), and the detection limit was 4.32 r 10-6 mol/L (S/N> 3). Meanwhile compound 2-4 was also applied to a pH (2.6-4.5) fluorescent sensor in CHsCN-Na3CeH5O7 (0.1 mol/L; 5/5, v/v) buffer solution.Near-infared dye 3-1 and 3-2 were developed with large stokes shift, and their sturctures were confirmed by’H NMR 13C NMR and ESI-MS. The absorption and fluorescence spectrum were studied in EtOH and CH2Cl2, and the sensitivity of the dyes was determined to different pH.The compound 3-1 could be used as a pH sensor (1.0-6.0,8.0-10.2). More importantly, due to its good soluble, it could be developed as a strong acid and alkali indicator. The colors of solution were carmine, purple, dark blue (pH= 2.0,3.0,4.0), and deep blue, bulish green, light green (pH= 10.0,11.0,12.0), respetively.The compound 3-2 could be applied to a pH sensor (2.0～6.0). It could be developed as a strong acid indictor which the colors of buffer solution changed from purple to dark blue in the pH of 2.0～3.0.