solution,compounds 1 and 2 also have good response towards the CN−. As shown in Fig. 3a, with the addition of the CN−, the absorbance of 1 at 425 nmslightly decreases from0.321 to 0.15. The response of compound
2 to CN− (Fig. S4a) is similar to that of 1 and the absorbance at 422 nm slightly decreases from 0.47 to 0.25, upon the addition of CN−. The detection limits (Fig. S5) are 2.42 μM (1) and 0.51 μM (2) with absorption
as detected signal, respectively. The detection limits (are 0.0004 μM(1) and 0.0002 μM(2)withfluorescence as detected signal, respectively.