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摘要
A rhodamine derivative, 3,6-bis(ethylamino)-2-(2-(2-hydroxy-5-methylbenzylideneamino)ethyl)-2,7-dimethylspiro[isoindoline-1,9-xanthen]-3-one (HL-Me), has been found to be a highly selective and sensitive fluorescent chemosensor for Al3+. It has been synthesized by condensation between N-(rhodamine-6G)lactam-ethylenediamine (L1) and 5-methylsalicylaldehyde (1:1) in acetonitrile and characterized by standard methods including single crystal X-ray diffraction analysis. Absorption and emission spectra have been obtained in 10 mM HEPES buffer at pH 7.4 in H2O/MeOH = 1:9 (v/v) at 25 degrees C. In the absorption spectra, HL-Me shows bands at 529 nm in the presence of Al3+. This metal ion turns the colorless solution of the probe to pink. Other metal ions fail to produce any color change. HL-Me is almost non-fluorescent when it is excited at 500 nm. But in the presence of Al3+, the emission intensity at 552 nm increases massively. No other metal ion is able to cause significant enhancement of the emission intensity. HL-Me is colorless and non-fluorescent due to the presence of the spirolactam ring. Al3+ induces the opening of the ring, leading to pink coloration and high fluorescence. Ring opening and the subsequent complex formation with the metal ion have been confirmed by H-1, C-13 NMR, IR and other spectral studies. The LOD is determined to be 2.8 nM. The quantum yield and life-time of the probe increase significantly upon complex formation with Al3+. HL-Me has been used for live cell imaging studies with different prokaryotic and eukaryotic cells. Reactions of L1 with salicylaldehyde with varying derivatives produce different rhodamine-based probes for different analytes. An attempt has been made to categorize the probe based on the substituent present in it with metal ion selectivity.
- 出版日期2018-6-7
