Highly selective chemosensors with versatile recognition ability caused by minor structural change

Two novel soluble chemosensors (L1, L2) modified by aza-crown ether groups have been synthesized by one-step facile reaction. The chemosensors were fully characterized by IR, 1H NMR, 13C NMR and MS spectra. The recognition abilities of two sensors with a range of metal ions were evaluated. The results showed that L1 was a specialized sensor for Cu2+ and L2 was a multi-functional sensor being able to recognize Al3+ and Cr3+ via two different optical behaviors, which demonstrated the subtle structural changes of sensors can have a remarkable effect on recognizing metal ions.