A symmetric Schiff base fluorescent “turn-on” chemosensor for aluminum (III) ion selective detection based on hydrolysis

A new symmetric Schiff base fluorescence turn-on chemosensor H2L (N,N′-bis[2,4-dihydroxy benzal]-1,5-diamino naphthalene) was designed and synthesized. H2L showed favorable selectivity and sensitivity to Al3+ with a significant color change from yellow to colorless in ethanol. The detection limit of H2L was as low as 11.79 nm. Based on fluorescence titration, 1H NMR and IR results, a plausible recognition mechanism of H2L is suggested to proceed via a hydrolysis process. The hydrolysis constant was calculated to be Kh = 3.0 × 104 M−1.