1. 贵州省大环化学及超分子化学重点实验室，贵州大学化学与化工学院，贵州 贵阳 550025
2. CSIRO Manufacturing Flagship, PO Box 218, NSW 2070, Australia
A Dual-Function Quinaldine Derivate Fluorescent Probe for Fe3+/F-
YUAN Jian-ying1, WU Yu-tian1, MU Lan1, ZENG Xi1*, WEI Gang2*
1. Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province; School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China
2. CSIRO Manufacturing Flagship, PO Box 218, NSW 2070, Australia
Abstract：A simple quinaldine derivative probe for cation and anion was investigated with spectroscopy. In probe molecular structure, the conjugate aromatic ring group was introduced at 2- of 8-hydroxyquinaldine to form a large conjugate structure, which enhances the photoluminescence quantum yield. N and O atoms of probe provide good coordination point, which can cooperate with ion selectivity and change its fluorescence properties. In CH3CN/H2O solution, probe emits blue fluorescence at 415 nm, however, Fe3+ led the fluorescence quenching. The 1∶1 stoichiometry of probe with Fe3+ was confirmed. IR spectrum and 1H NMR titration spectra speculated that the nitrogen of quinaldine group and the two carboxylate oxygen are involved in the complexation, inducing photoinduced electron transfer transfer process cause the fluorescence quenching. The complexation was an exothermic reaction driven by entropy processes. In CH3CN solution, the emission intensity of probe at 415 nm reduced when a new emission appeared at around 560 nm with the addition of F-, blue fluorescence changed to yellow, exhibited a ratio fluorescence emission. The absorption bands at 280 and 340 nm reduced while a new absorption appeared around at 455 nm with the addition of F-, exhibited a ratiometric absorbance, and the color changed from colorless to orange, which could be observed by the naked eye. It is noteworthy that the ratio fluorescence/absorbance change could be potentially useful for the quantitative determination of F-. 1H NMR titration spectra speculated that the reaction of probe and F- through hydrogen bonding effect. The probe can monitor Fe3+ and F- simultaneously as a dual-function chemsensor, and the limit of detection are 13.6 nmol·L-1 and 1.6 μmol·L-1 by fluorescence spectroscopy，and the limit of detection is 16.5 μmol·L-1 to F- by absorption spectroscopy. Making use of the obvious color change of probe with F- for both visible light and fluorescence could be readily distinguished by the naked eyes. A method of visual detection of trace F- was established with intuitionistic, rapid, sensitive and easy operability.
