title: A multi writable thiophene-based selective and reversible chromogenic fluoride probe with dual -NH functionality.
abstract: A chromogenic fluoride probe bearing bis imine groups having dual -NH functionality (BSB) has been designed, synthesised and structurally characterized by its single crystal X-ray diffraction studies. The BSB could visually and spectroscopically recognise F(-) with high selectivity over other anions by exhibiting intense chromogenic response (from colourless to red) for F(-) in acetonitrile solution. The UV-visible titration and (1)H NMR titration experiments indicated that the observed changes occur via a combined process including hydrogen bonding and deprotonation between the BSB and F(-). Moreover theoretical calculations at the Density Functional Theory (DFT) level shed further light upon probe design strategy and the nature of interactions between BSB and F(-). The limit of detection and binding constant of BSB towards F(-) were found to be 6.9×10(-7)M and 1.42±0.069×10(8)M(-2) respectively. Finally, by using F(-)and H(+) as chemical inputs and the absorbance as output, a INHIBIT logic gate was constructed, which exhibits "Multi-write" ability without obvious degradation in its optical output.
authors.affiliation: Department of Chemistry (Centre of Advanced Study), Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Vishwakarma
authors.affiliation: Department of Applied Sciences & Humanities, National Institute of Foundry & Forge Technology, Ranchi 834003, Jharkhand, India.
authors.forename: Ajit
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Chemistry (Centre of Advanced Study), Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India.
authors.forename: Abha
authors.initials: A
authors.lastname: Pandey
authors.affiliation: Department of Chemistry (Centre of Advanced Study), Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India. Electronic address: drkaushalbhu@yahoo.co.in.
authors.forename: K K
authors.initials: KK
authors.lastname: Upadhyay
keywords: Chromogenic sensor; Density functional theory; Fluoride; Logic gate; bis-Schiff base