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A novel aggregation-induced emission (AIE) active linear conjugated bis-Schiff base compound, ( E )- N , N ′-bis(4-( Z )-2-(4-butoxyphenyl)-1-cyanovinylphenyl)-1,4-benzenebismethaneimine ( 4 ) containing α-cyanostilbene unit was designed, synthesized and characterized. The distinct change of color and/or fluorescence emission of 4 + Hg 2+ in tetrahydrofuran (THF) and THF/water solution provided a simple and easy discrimination way for Hg 2+ by “naked eye” or using a UV lamp. The aggregating patterns of 4 were applied to explain the mechanism of sensing. The as-synthesized sample showed comparatively high selectivity and sensitivity to Hg 2+ through fluorescence “turn-on” response with a low detection limit (3.4 × 10 −9 M in THF, 2.4 × 10 −7 M in THF/water). The results implied that the as-made sample could effectively act as Hg 2+ sensor not only in THF and THF/water but in living cells. [ABSTRACT FROM AUTHOR]

A new versatile ‘dual’ chemosensor 1 has been synthesized for Zn 2+ and Co 2+ . The sensor 1 comprises of quinoline as a fluorophore and N 1 , N 1 -dimethylethane-1,2-diamine as a water-soluble functional group. Sensor 1 showed a remarkable fluorescence enhancement in the presence of Zn 2+ in aqueous solution. The sensor 1 also acted as a colorimetric sensor for Co 2+ by changing its color from colorless to yellow. Importantly, the chemosensor 1 could be used to quantify Zn 2+ and Co 2+ in water samples and to image and quantify Zn 2+ in living cells. Moreover, the sensing mechanisms of 1 for Zn 2+ and Co 2+ were supported by theoretical calculations. Therefore, this sensor has the ability to be a practical system for monitoring Zn 2+ and Co 2+ concentrations in biological systems and aqueous samples. [ABSTRACT FROM AUTHOR]

A rhodamine derivative ( 1 ) is developed as a fluorescent chemosensor for trivalent chromium ions (Cr 3+ ). It exhibits a highly sensitive “turn-on” fluorescent response toward Cr 3+ with a 55-fold fluorescence intensity enhancement under 2 equiv. of Cr 3+ added. The chemosensor can be applied to the quantification of Cr 3+ with a linear range covering from 5.0 × 10 −7 to 2.0 × 10 −5 M and a detection limit of 1.7 × 10 −7 M. Most importantly, the fluorescence changes of the chemosensor are remarkably specific for Cr 3+ in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the response behavior of 1 toward Cr 3+ is pH independent in neutral condition (pH 6.0–8.0). The response of the chemosensor is fast (less than 2 min) and the chemosensor is chemically reversible. Furthermore, the ring-opening mechanism of the rhodamine spirolactam induced by Cr 3+ and the 1:1 stoichiometric structure between 1 and Cr 3+ were supported by Job's plot, NMR, MS and DFT theoretical calculations. In addition, the proposed chemosensor has been used to detect Cr 3+ in real water samples and image Cr 3+ in living cells with satisfying results. [ABSTRACT FROM AUTHOR]