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

The host–guest binding characteristics of cyclopentanocucurbit[6]uril (CyP6Q[6]) and cyanine dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (t-DSMI) have been studied. The results show that CyP6Q[6] and t-DSMI form a 1:1 inclusion system, generating strong fluorescence. On this basis, the fluorescent probe t-DSMI@CyP6Q[6] has been constructed, and its anion recognition ability has been investigated. In a neutral environment, BF4−, H2PO4−, 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]. Since the complex formed by CyP6Q[6] and t-DSMI can produce strong fluorescence at pH > 4.6, t-DSMI@CyP6Q[6] was constructed to recognize the anions at pH ≅ 5. The results show that in a near neutral environment, BF4−, H2PO4−, and I− elicit obvious specific responses from the probe. [ABSTRACT FROM AUTHOR]