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

Sabeel M Basheer; M Muralisankar; T V Anjana; K N Aneesrahman; Anandaram Sreekanth

doi:10.1016/j.saa.2017.04.002

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

Spectrochim Acta A Mol Biomol Spectrosc. 2017 Jul 5:182:95-104. doi: 10.1016/j.saa.2017.04.002. Epub 2017 Apr 4.

Authors

Sabeel M Basheer¹, M Muralisankar¹, T V Anjana¹, K N Aneesrahman¹, Anandaram Sreekanth²

Affiliations

¹ Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015, India.
² Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015, India. Electronic address: sreekanth@nitt.edu.

PMID: 28410491
DOI: 10.1016/j.saa.2017.04.002

Abstract

The selective chemosensing behaviour of imidazole bisthiocarbohydrazone (IBTC) towards F^- and Cu²⁺ are studied via colorimetric, UV-Visible, fluorescence spectra studies, and binding constants were calculated. The ¹H 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 (ClO₄^-) 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 Ca²⁺ and F^-. The multi-ion detection of IBTC was used to construct the NOR, OR and INHIBITION molecular logic gates.

Keywords: Chemosensor; Molecular logic gate; Molecular switches; Sensing mechanism; TDDFT.