Chromogenic signaling of water traces by 1,8-naphthalohydrazone-anion complex in organic solvents

A naphthalo-1, 8-bis[(2,4-dinitrophenyl)hydrazone] sensor (K) was synthesized and characterized using UV–vis, 1H NMR and fluorescence spectroscopy. The sensor showed strong colorimetric and spectral response upon the molar addition of acetate or fluoride ion (AcO− or F−) in acetonitrile. The complexed state (KF or KAcO) of the system showed significant reversibility properties, both in color and spectra, upon the addition of small traces of water. Subsequently, in addition to sensing of fluoride or acetate ions, the complexed KF or KAcO adducts can be used in colorimetric signaling of water traces in different organic mediums. In order to have more understanding of the interaction between K and the anions, the study was supplemented using density functional theory computations.

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