Intracellular application and logic gate behavior of a 'turn off-on-off type probe for selective detection of Al3+ and F- ions in pure aqueous medium

A new Schiff base tcph, derived from 2-thiophene carboxylic acid hydrazide, has been synthesized and characterized by various spectroscopic techniques. The molecular structure of the compound has also been determined by X-ray crystallography. The tcph acts as a selective Al3+ and F- induced OFF-ON-OFF type of probe in aqueous media. The 1:1 binding stoichiometry between probe and Al3+ has been established from Jobs plot and further supported by ESI-MS studies. The limit of detection of Al3+ ions is determined by 3s methods, which is found to be 1.35 x 10(-9) M. The coordination environment for the tcph-Al3+ complex is delineated by NMR titration and DFT calculations. Detailed insights of probe-metal interaction mechanism have been studied by density functional theory (DFT) as well as time dependent-DFT calculations. MTT assay of the probe on live SiHa cells suggests no serious cytotoxicity in cells even at higher concentration. The probe tcph and its tcph-Al3+ complex have also been successfully applied to detect Al3+ and F- ions in living cells (SiHa cells), respectively. (C) 2017 Elsevier B.V. All rights reserved.