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 (original) (raw)

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 Al 3+ and F − induced OFF-ON-OFF type of probe in aqueous media. The 1:1 binding stoichiometry between probe and Al 3+ has been established from Job's plot and further supported by ESI-MS studies. The limit of detection of Al 3+ ions is determined by 3 methods, which is found to be 1.35 × 10 −9 M. The coordination environment for the tcph-Al 3+ 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-Al 3+ complex have also been successfully applied to detect Al 3+ and F − ions in living cells (SiHa cells), respectively.