A new 7-(diethylamino)coumarin and 4-(diethylamino)phenol appended unsymmetrical thiocarbohydrazone: Detection of moisture in organic solvent and sequential fluorimetric detection of Cu2+ ions and cysteine

Abstract

A novel 7-(diethylamino)coumarin and 4-(diethylamino)phenol appended unsymmetrical thiocarbohydrazone (2) was designed and synthesized successfully. The probe 2 forms an interesting three dimensional hydrogen bonded network results in an interesting supramolecular network. The compound, 2 showed fluorometric and colorimetric response towards fluoride anion via deprotonation process due to the presence of phenolic –OH and –NH groups. The anionic species 2-F− was successfully employed for the detection of moisture in organic solvents through the reprotonation process. The moisture detection features of 2-F− were explored by using UV–vis and emission experiments in DMF solvent and the corresponding mechanism was effectively confirmed by 1H NMR spectral analysis. Moreover, the synthesized probe 2 exhibits highly selective and sensitive detection for Cu2+ ions. Furthermore, the 2-Cu2+ ensemble might be used as a highly selective sensor for Cys in the presence of other amino acids without any interference. Further, the potential reversible sensing feature of Cu2+ and Cys by 2 were recognized to develop the INHIBIT logic gate function and on-site detection of Cu2+ ions and Cys by a paper strip applications.