Research of a highly selective fluorescent chemosensor for aluminum(III) ions based on photoinduced electron transfer

•The Salen base H2L exhibits high selectivity for Al3+ ions.•The sensing mechanism can be explained by photoinduced electron transfer.•The combination mode of the H2L–Al complex is studied.

A highly selective fluorescent chemosensor for aluminum(III) ions, N,N′-bis(2-hydroxy-1-naphthaldehyde)-l,2-phenylenediamine (H2L) was synthesized and characterized. When aluminum(III) ions are added to H2L solution in DMF, the solution exhibits two remarkably enhanced emissions at 517 and 540 nm, which could not be observed with other metal ions. The results of 1H NMR titration, MALDI-TOF-MS and DFT studies indicate that H2L and aluminum(III) ions form a 1:1 complex. The association constant Ka was determined to be 2.67 × 106 and the limit of detection (LOD) was calculated to be 10−6 M. The sensing mechanism can be explained by the photoinduced electron transfer (PET).

Graphical abstractA highly selective fluorescent chemosensor for aluminum(III) ions was synthesized and characterized. 1H NMR titration, MALDI-TOF-MS and DFT studies are used to study the combination mode. The sensing mechanism can be explained by the photoinduced electron transfer (PET).Figure optionsDownload full-size imageDownload as PowerPoint slide