A novel high-yield Schiff base was designed and synthesized as an anion receptor that specifically select HSO3 anions in aqueous solutions of H20/DMSO(15:85, volume ratio), which can be detected via colorimetry under direct visualization. The sensor exhibited different results for other anions, such as F, CI, Br, I-, H2PO4-, AcO-, HSO4 and C104. The changes in the UV-Vis spectra also show the specific recognition of HSO3 , rather than similar anions H2PO4- and HSO4- in the same aqueous solution. The detection limit of HSO3- was 1×10-6 mol/L.
YANG Wen-long LI Qiao WEI Tai-bao ZHANG You-ming LIN Qi SHI Bing-bing ZHANG Peng
By applying an indirect strategy, a new copper (Ⅱ) complex of a thiosemicarbazone L has been successfully developed as a colorimetric chemosensor for the sensitive detection of mercury (Ⅱ) ions. In the presence of copper (Ⅱ) ions, the colorless solution of L became yellow; however, upon the addition of traces of mercury (Ⅱ) ions, the yellow color faded to colorless immediately. Other ions, including Fe3+ , Ag+ , Ca2+ , Zn2+ , Pb2+ , Cd2+ , Ni2+ , Co2+ , Cr3+ and Mg2+ had a negligible influence on the probe behavior. The detection limits were 5.0×10 -6 M and 3.0×10 -7 M of Hg2+ using the visual color changes and UV-vis changes respectively. Test strips based on Cu-L were fabricated, which could act as a convenient and efficient Hg2+ test kits.
A non-sulfur chemosensor based on an easy to prepare double naphthalene Schiff base is reported for the colorimetric and fluorometric dual-channel sensing of Hg2+ ions by taking advantage of the twisted intramolecular charge transfer (TICT) mechanism. This work provides a novel approach for the selective recognition of mercury ions. Moreover, this sensor serves as a potential recyclable component in sensing materials and the complex L-Hg2+ (L = 1-[(2-naphthalenylimino)methyl]-2-naphthalenol) can therefore be used as a fluorescent sensor for iodine anions. Notably, the color changes are very significant and all the recognition and recycling processes can be observed by the naked eye.