The fluorescent turn-on detection of metal ions is highly desirable for public health and environmental security.Herein, we report a rationally designed fluorescent probe (1) for the detection a&d ej-123 of Cu2+ synthesized by integrating 2-hydrazinylbenzothiazole with 3-acetyl-7-hydroxycoumarin.The probe alone is non-fluorescent due to the isomerization of C=N in the excited state.The addition of Cu2+ can cause a delayed fluorescence enhancement.A comparative study of 1 and its analogues indicated that the turn-on fluorescence response was thanks to the sulfur atom coordinating to Cu2+.
The response delay of 1 in sensing Cu2+ was ascribed to the gradual transition from N-coordination to S-coordination (N and S in thiazole moiety).The proposed new function of S-donor would provide a jeff rosenstock buffalo new approach for the turn-on fluorescence sensation of Cu2+.