Synthesis And Study Of Fluorescent Probe On Sand-wich Rhodamine-B And Investigation Of Their Spectra Properties

The fluorescence group and the recognition group are two very important constituents of the fluorescent molecular probe. When their chemical or physical environment outside were changed, the fluorescent properties of fluorophores (such as:quantum yield, excitation and emission wavelengths, fluorescence intensity, fluorescence lifetime) will be changed significantly. Rhodamine-B fluorescence group has attracted chemists’interests because of its excellent photophysical properties, high fluorescence quantum yield, available reagents and simple products.Eleven novel Rhodamine-B derivatives were synthesized, and their structures were confirmed by IR, ESI-MS,1H NMR, and13C NMR.The selectivity of the Rhodamine-B derivatives on metal ions was studied through the fluorescence and the absorption spectrum. The stoichiometric ratio of Rhodamine-B derivatives to metal ions was also confirmed by fluorescence titration spectra and Job-Plot method.Experiment results showed that:1:L3showed high selectivity for Hg2+in Ethanol-water. When Hg2+was added into the solution of L3, the color of solution changed from colorless to purple red. L3also showed considerably selectivity for Hg in Ethanol-H2O buffer solution (pH=3-10).2:L6displayed high selectivity for Fe3+. The changing of color of the solution suggested that L6can serve as a conveniently "naked-eye" detect for Fe3+. The coordinated with Fe3+of L6was a reversible process.3:L10showed excellent selectivity for Cu2+in ethanol.