A novel fluorescent sensor for Al3+ based on a new diarylethene with a naphthalimide unit

A new fluorescent sensor for Al3+ based on a photochromic diarylethene with a naphthalimide unit has been synthesized. Its photochromic and fluorescent properties with UV/Vis light and Al3+/EDTA were investigated systematically in methanol. The fluorescent sensor was highly selective toward Al3+ with obvious emission intensity change (enhanced more than 20-fold) and color change (dark to orange-yellow). The Job's plot showed the 1:1 complex of the sensor with Al3+. Moreover, the complexation mechanism of the sensor with Al3+ was confirmed by the ESI-MS and 1H NMR titration experiment. The binding constant (Ka) was 2.55 × 105 mol−1 L and the limit of detection of the sensor for Al3+ was calculated to be 1.75 × 10−7 mol L−1. In addition, the metal-responsive fluorescence behavior of the sensor was applied successfully to the construction of molecular logic circuit.