Multi-ion detection and molecular switching behaviour of reversible dual fluorescent sensor.

The selective chemosensing behaviour of imidazole bisthiocarbohydrazone (IBTC) towards F and Cu are studied via colorimetric, UV-Visible, fluorescence spectra studies, and binding constants were calculated. The H NMR titration study strongly support that the deprotonation of IBTC followed by the hydrogen bond formation via N1H1 and N2H2 protons with fluoride ion. The fluorescence inactive IBTC-Cu complex became fluorescence active in the presence of perchlorate (ClO) ion. The selective detection of perchlorate ion was also explained. The F sensing mechanism of IBTC has been investigated by Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) methods. The theoretical outcomes well reproduce the experimental results. And it concluded the NH protons, nearby the imine group was first captured by the added F ion and then deprotonation happened followed by the formation of hydrogen bond. The IBTC found good reversibility character with the alternative addition of Ca and F. The multi-ion detection of IBTC was used to construct the NOR, OR and INHIBITION molecular logic gates.