Sequential displacement strategy for selective and highly sensitive detection of Zn2+, Hg2+ and S2- ions: An approach toward a molecular keypad lock

Subrata Kumar Padhan; Jitendra Palei; Punam Rana; Narayan Murmu; Satya Narayan Sahu

doi:10.1016/j.saa.2018.10.016

Sequential displacement strategy for selective and highly sensitive detection of Zn²⁺, Hg²⁺ and S^2- ions: An approach toward a molecular keypad lock

Spectrochim Acta A Mol Biomol Spectrosc. 2019 Feb 5:208:271-284. doi: 10.1016/j.saa.2018.10.016. Epub 2018 Oct 15.

Authors

Subrata Kumar Padhan¹, Jitendra Palei¹, Punam Rana¹, Narayan Murmu¹, Satya Narayan Sahu²

Affiliations

¹ School of Chemistry, Sambalpur University, Jyoti Vihar, Burla 768 019, Odisha, India.
² School of Chemistry, Sambalpur University, Jyoti Vihar, Burla 768 019, Odisha, India. Electronic address: snsahu@suniv.ac.in.

PMID: 30340207
DOI: 10.1016/j.saa.2018.10.016

Abstract

A thiocarbonohydrazone locked salicylidene based macrocycle ligand L has been synthesized and its ion sensing properties were examined by UV-visible and fluorescence spectroscopy. The macrocycle serves as a highly selective colorimetric sensor for Hg²⁺ ions while it acts as an excellent fluorescent sensor for Zn²⁺ ions by exhibiting a green fluorescence at 498 nm even in the presence of interfering ions. A detailed analysis of binding characteristics such as complex stoichiometry, association constant and detection limits of L toward Hg²⁺ and Zn²⁺ ions were evaluated by UV-visible and fluorescence experiments which revealed a stronger binding affinity and higher detection limit of L toward the mercury ions. Further, the sequential displacement strategy for the chromofluorogenic detection of Zn²⁺, Hg²⁺ and S^2- ions by ligand L, has been studied comprehensively. Finally, the ion-responsive fluorescence output signal of L were employed to design a molecular keypad lock which could be accessible by two users having two different set of chemical passwords (inputs) through distinguishable optical trajectories.

Keywords: Chromofluorescent; Displacement strategy; Macrocycle; Mercury; Molecular keypad lock; Salicylidene; Sulphide; Thiocarbonohydrazone; Zinc.