The sensor HNHCB (3-hydroxy-naphthalene-2-carboxylic acid (4-cyano-benzylidene)-hydrazide) comprises a -CONH- group, -OH group, -CHN- linkage and an electron withdrawing -CN group that can act as both an anion (fluoride) and a cation (copper) sensor by two distinct output modes. It can detect fluoride by naked eye color change and copper by fluorescence enhancement. Interestingly, the nature of the substituent in HNHCB has an effect on the selectivity. The detection limit can be as low as 160 nM for Cu2+ and 1.3 μM for F-. DFT calculations have been performed to demonstrate the structure of HNHCB and its copper complex. Biological applications of HNHCB have been evaluated in HEK 293 and it was found to exhibit membrane permeability for the detection of Cu2+. The sensor HNHCB is also sensitive towards fluoride in commercially available toothpaste. © The Royal Society of Chemistry 2016.

NIKHIL GUCHHAIT

Chemistry

S GHOSH

A GANGULY

A BHATTACHARYYA

M A ALAM

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

RSC Advances

An asymmetric hydrazide, (12E, 13E)-2-((naphthalen-1-yl) methylene)-1-(1-(2-hydroxynaphthalen-6-yl) ethylidene) hydrazine (abbreviated as AH) is synthesized and characterized by standard techniques and crystal structure of AH has been obtained. The naked eye detection of F − in aqueous acetonitrile (acetonitrile: water = 7:3/v:v) by AH has been investigated by UV–Visible titration and in presence of other anions, the limit of detection being 1.31 × 10 −6 (M). The mechanism of F − sensing has been explored by 1 H NMR titration. AH undergoes hydrogen bonding with F − followed by deprotonation. The practical utility of AH has been explored by successful test kit response and color change in toothpaste solution. © 2018 Elsevier B.V.

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

Employing a hydrazine linked asymmetric double naphthalene hybrid for efficient naked eye detection of F âˆ’ : Crystal structure with real application for F âˆ’

Selective chromo-fluorogenic molecular sensor for dual channel recognition of Cu2+ and F-: Effect of functional group on selectivity

A series of Schiff bases synthesized by the condensation of benzohydrazide and -NO<inf>2</inf> substituted benzaldehyde have been used as selective fluoride ion sensor. Test paper coated with these synthetic Schiff bases (test kits) can detect fluoride ion selectively with a drastic color change and detection can be achieved by just using the naked-eye without the help of any optical instrument. Interestingly, the position of -NO<inf>2</inf> group in the amido Schiff bases has an effect on the sensitivity as well as on the change of color of species. © 2015 Elsevier B.V. All rights reserved.

Amido-Schiff base derivatives as colorimetric fluoride sensor: Effect of nitro substitution on the sensitivity and color change

A Schiff base 2, composed with o-phenylenediamine and 5-nitro- salicylaldehyde have been synthesized as an anion receptor. It consists with conjugated imine, phenolic -OH and electron withdrawing substituent nitro (-NO2) group. Receptor 2 can recognize selectively biologically important F- and AcO- ions. The recognition properties have been investigated by naked-eye color change (colorless to yellow), followed by UV-vis spectral changes. Predicted stoichiometries of the complexes between receptor 2 and anions based on density functional theory (DFT) level calculations, corroborates well with experimental findings. © 2011 Elsevier B.V. All rights reserved.

Journal of Fluorine Chemistry

Naked-eye detection of F- and AcO- ions by Schiff base receptor

Unsymmetrical azine Schiff base 5-diethylamino-2-[(4-diethylamino- benzylidene)-hydrazonomethyl]-phenol (receptor 1) having multiple binding sites (-NEt2 and -OH group) have been synthesized. The receptor 1 exhibits color change from light yellow to purple and bright yellow in presence of Cu2+ ion and Fe3+ ion, respectively which is detectable by naked-eye. But it shows red color in presence of mixture of all metal ions. The UV-vis spectral investigation of receptor 1 shows a remarkable spectral shift from 410 nm to 527, 572 and 620 nm in presence of Cu2+ ion and 485 nm in presence of Fe3+ ion in acetonitrile solvent. Interestingly, Cu2+ ions generates a new charge transfer emission band at 532 nm in the expense of local emission of receptor at 480 nm, but Fe3+ ion only quenched the local emission. The spectral response of receptor is almost insignificant in presence of other metal ions (Mn2+, Zn2+, Co2+, Ni2+, Cd2+, Hg2+, Li + and Na+ ions). © 2011 Elsevier B.V. All rights reserved.

Journal	Data powered by TypesetRSC Advances
Publisher	Data powered by TypesetRoyal Society of Chemistry
ISSN	2046-2069
Open Access	No