A new multifunctional Schiff base as a fluorescence sensor for Al3+ and a colorimetric sensor for CN- in aqueous media: an application to bioimaging

A multifunctional fluorescent and colorimetric receptor 1 ((E)-N'-((8-hydroxy-1,2,3,5,6,7-hexahydropyrido-[3,2,1-ij]quinolin-9-yl) methylene) benzohydrazide) for the detection of both Al3+ and CN- in aqueous solution has been developed. Receptor 1 exhibited an excellent selective fluorescence response toward Al3+. The sensitivity of the fluorescent based assay (0.193 mu M) for Al3+ is far below the limit in the World Health Organization (WHO) guidelines for drinking water (7.41 mu M). In addition, receptor 1 showed an excellent detection ability in a wide pH range of 4-10 and also in living cells. Moreover, receptor 1 showed a highly selective colorimetric response to CN(-)by changing its color from colorless to yellow immediately without any interference from other anions.