A highly selective novel multiple amide based Schiff base optical chemosensor for rapid detection of Cu2+ and its applications in real sample analysis, molecular logic gate and smart phone

A novel multiple amide based Schiff base chemosensor L has been designed rationally for selective colorimetric detection of Cu2+ ion in CH3OH-H2O (1:1 v/v, triS HCl buffer 10 mu M, pH = 7.2) solution. The colour change (colourless to yellow) is so prominent to be visible in bare eye. From the absorption titration, job's plot measurement and ESI-MS revealed that receptor-analyte binding occurs in a 2:1 fashion and the binding sites were confirmed by the X-ray single crystal structure of host-guest complex. Solvent dependent crystal structure from a homoleptic monomer to 2D polymer was observed. The detection limit was found to be 1.8 mu M with the association constant value 1.3 x 10(2) M-1/2 which is highly desirable for 2:1 complexes. The chemosensor L has been applied for construction of binary logical device, recovery of contaminated water samples and smart-phone based analysis.