[Spiropyran-based fluorescent sensor for Hg2+, Cr3+, Ag+ and their interaction spectra].

A 6',8'-di-tert-butyl-1-hydroxyethyl-3,3-dimethyl-indoline benzospiropyran L1 and its derivative L2 were synthesized and characterized. Chelation-enhanced appearswhen L1 with electron donating groups of 6', 8'-di-tert-butyl touch on benzospiropyran and affect the stability of cyanine structure. L1 exhibited high selectivity to Hg2+, Cr3+, Ag+ over other metal ions. While, there was no obvious interferences of coexist metal ions on Hg2+, Cr3+, Ag+ detection. The Hg2+, Cr+, Ag+ recognition of L1 not only could be achieved by means of fluorescense and absorption "turn-on" spectra but also an obvious color change from colorless to yellowish by naked-eyes. The binding of L1 to Ag+, Cr3+, Hg2+ are in 1 : 1 stoichometry and the detection limits are 7.435 8 x 10(-6), 6.126 8 x 10(-6), 3.452 4 x 10(-6) mol x L(-1). The sensing mechanism was also investigated from L2.