A simple, selective, fluorescent iron(III) sensing material based on peripheral carbazole

The fluorescent material M1 (4-poly[9,9′-(N-carbazole-hexyl) fluorene]) is a fluorene tetramer with eight peripheral carbazole side chains acted as the metal ions recognized units. During metal ion recognition, M1 exhibits excellent fluorescence quenching sensitivity towards Fe3+. The fluorescent detection ranges from 5 × 10−6 M to 2 × 10−4 M. Additionally, the effect of the carbazole side chains is studied by the comparison of M1 with M2 ([2,7-(9,9-dihexylfluorene)]) and M3 (poly[2,7-(9-(2-ethyloctyl)-carbazole)]). Results show that the introduction of carbazole groups is beneficial for ion detection and their location on the peripheral side chains could improve the sensitivity of fluorescence detection. Thus, M1 displays a promising future for application in metal ion sensing.