trans-4-[4-(Dimethylamino)styryl]-1-methylpyridinium iodide@cyclopentanocucurbit[6]uril as a fluorescent probe for anion recognition

Abstract The host–guest binding characteristics of cyclopentanocucurbit[6]uril (CyP 6 Q[6]) and cyanine dye trans -4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide ( t -DSMI) have been studied. The results show that CyP 6 Q[6] and t -DSMI form a 1:1 inclusion system, generating strong fluorescence. On this basis, the fluorescent probe t -DSMI@CyP 6 Q[6] has been constructed, and its anion recognition ability has been investigated. In a neutral environment, BF 4 − , H 2 PO 4 − , and I − elicit obvious specific responses from the probe, since they have stronger binding forces. This probe shows greater sensitivity than the previously reported probe t -DSMI@HMeQ[6]. Graphic abstract Since the complex formed by CyP 6 Q[6] and t -DSMI can produce strong fluorescence at pH > 4.6, t -DSMI@CyP 6 Q[6] was constructed to recognize the anions at pH  ≅  5. The results show that in a near neutral environment, BF 4 − , H 2 PO 4 − , and I − elicit obvious specific responses from the probe.