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A new Schiff base receptor (3) was synthesized by an equimolar reaction between the isonicotinic hydrazide and 2,4-dihydroxybenzaldehyde in ethanol. Receptor 3 based demonstrated excellent selectivity and sensitivity towards Cu2+...

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A new Schiff base receptor 1 was synthesized and its photophysical properties were investigated by absorption, emission and excitation techniques. Furthermore, its chromogenic and fluorogenic sensing abilities towards various metal ions were examined. Receptor 1 selectively detects Cu ion through fluorescence quenching and detection was not inhibited in the presence of other metal ions. From fluorescence titration, the limit of detection of receptor 1 as a fluorescent 'turn-off' sensor for the analysis of Cu was estimated to be 0.35 μM.

A new terephthaldehyde-based chemosensor 1 bearing an aminophenol recognition unit has been synthesized and applied to the fluorescent sensing of metal ions. Molecular system 1 acts as a highly selective and sensitive fluorescence turn-on sensor for Cu. The sensing mechanism has been explored. It is proposed that Cu binds with the imine and hydroxyl moiety of 1 in 1 : 2 binding stoichiometry, thereby enhancing the fluorescence at 386 nm. The detection limit and association constant (K) of 1 with Cu were found to be 0.62 μM and 6.67 × 10 M, respectively. Chemosensor 1 has shown excellent specificity towards Cu and has been successfully applied to the determination of Cu in live L929 cells.