A novel selective colorimetric chemosensor for Cu^{2 +}in aqueous solution

A novel chemosensor 1 (1 = 2-(N-(2-hydroxybenzyl)-N-((pyridin-2-yl)methyl)amino)-N-(2-hydroxyphenyl)acetamide) was synthesized and characterized. The receptor 1 showed a selective colorimetric sensing ability for copper (II) ion by changing color from colorless to yellow in aqueous solution, facilitating naked eye detection of Cu^{2 +}. This phenomenon could be possibly explained by ligand-to-metal charge-transfer. Moreover, 1 could be utilized to monitor Cu(II) over a wide pH range of 3-11. Job plot and ESI-mass analysis indicate the formation of a 1:1 complex of 1 with Cu^{2 +}.