A new multifunctional Schiff base as a fluorescence sensor for Al³âº 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 Al(3+) and CN(-) in aqueous solution has been developed. Receptor 1 exhibited an excellent selective fluorescence response toward Al(3+). The sensitivity of the fluorescent based assay (0.193 µM) for Al(3+) is far below the limit in the World Health Organization (WHO) guidelines for drinking water (7.41 µM). 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.

A colorimetric organic chemo-sensor for Co²âº in a fully aqueous environment.

A new highly selective and sensitive colorimetric chemosensor 1 for Co(2+) was developed. The receptor 1 sensed Co(2+) by changing its color from yellow to orange in aqueous solution. Moreover, 1 could be used as a practical, visible colorimetric test kit for Co(2+).

A colorimetric "naked-eye" Cu(II) chemosensor and pH indicator in 100% aqueous solution.

A new, highly selective and sensitive colorimetric chemosensor 1 for detection of Cu(2+) ions in aqueous solution was developed. Receptor 1 detected Cu(2+) ions by changing its color from colorless to yellow. Moreover, the Cu(2+)-sensitive compound was used as a colorimetric pH detector based on a color change due to 1-Cu(2+) complex formation identifiable by the naked eye.