A reversible colourimetric and selective fluorescent chemosensor for the cascade recognition of Cu²⁺ and H₂PO₄ ^- in aqueous solution

This report describes a reversible colourimetric and on–off–on module of fluorescent chemosensor for selective cascade recognition of Cu²⁺ and H₂PO₄ ^-with unique output optical response in aqueous solution. On the other hand, F^-, Cl^-, Br^-, I^-, CH₃COO^-, HSO₄ ^-, ClO₄ ^-, CN^- and SCN^- did not induce significant changes in fluorescence. Moreover, the colour change in chemosensor LH by response of this colourimetric chemosensor can be visualised by naked eye. These fluctuations in spectral response, under electronic behaviour, can be viewed to mimic as IMPLICATION logic gate. (Figure presented.) The proposed structures of LH for Cu²⁺ and LH –Cu²⁺ for H₂PO₄ ⁻ anions.