Developing new Schiff base molecules for selective colorimetric sensing of Fe3+ and Cu2+ metal ions: Substituent dependent selectivity and colour change

New Schiff base chemosensors (1-5) based on aryl ether amine were synthesized and explored the colorimetric sensing of metal ions. A highly selective colorimetric sensing of Fe3+ ions was observed with 1 and 2. Addition of Fe3+ leads to selective decolourisation of yellow colour. But naphthaldehyde based chemosensor, 3, exhibited selective disappearance of yellow colour for Cu2+ ions. On the other hand, diethylamine substituted chemosensor, 4, showed generation of clear strong yellow colour selectively for Fe3+ and Hg2+ ions. Similarly, 5 also showed generation of yellow colour from colourless solution upon addition of Fe3+ selectively. The concentration dependent studies of 1-5 revealed the ppm level detection of metal ions. The interference studies demonstrate the high selectivity of Fe3+ and Cu2+ in the presence of other metal ions. (C) 2014 Elsevier B.V. All rights reserved.