Simple naked-eye colorimetric chemosensors based on Schiff-base for selective sensing of cyanide and fluoride ions

2016 ◽  
Vol 94 (7) ◽  
pp. 631-636 ◽  
Author(s):  
Asadollah Mohammadi ◽  
Jeyran Jabbari

The present work describes the design and synthesis of simple colorimetric chemosensors based on Schiff-base for highly selective sensing of cyanide and fluoride ions. The chemosensor S2, containing an electron withdrawing group (EWG), displayed selective sensing properties for both cyanide and fluoride ions. The interaction of S2 with F– and CN– ions provides remarkable colorimetric responses from yellow to purple, enabling naked-eye sensing without any spectroscopic instrumentation. The mechanism of anion binding with chemosensor S2 showed one-to-one stoichiometry by Job’s plot. The mechanism of interaction between the S2 and CN– ions has been confirmed by the 1H NMR titration experiments. Furthermore, the detection limits of chemosensor S2 towards F– and CN– ions were found to be 3.7 and 1.2 μmol/L, respectively.

2021 ◽  
Vol 05 ◽  
Author(s):  
Santanu Panja ◽  
Kumaresh Ghosh

Aim: Design and synthesis of new molecules capable of forming self-assembled gels are indispensable to harvest new functional materials. Supramolecular gels have potential in many areas particularly in biology and materials chemistry. Of the different types of applications, visual sensing of biologically relevant ionic analytes is a fairly recent trend. Here we describe naked eye detection of fluoride ions involving sol-gel methodology. Methods: To execute this, cholesterol substituted pyridinium salts 1-4 have been designed and synthesized of which compounds 3 and 4 served as potential gelators for the naked eye detection of F- ions in DMSO and DMSO-H2O (1:1, v/v) respectively. Results: Gelation study reveals that not only the aromatic surface is crucial for the self-aggregation of molecules via π-π stacking interactions, but also polarity, rigidity and conformational flexibility of the molecules that govern the intermolecular association of gelators are important. Conclusion: Moreover, incorporation of fluorophores (naphthalene) as aromatic surface in the molecular designs, promotes the gelator molecules to execute sensing behavior for F- with high degree of sensitivity in solution phase also.


2019 ◽  
Vol 97 (5) ◽  
pp. 387-391 ◽  
Author(s):  
Jiayi Sun ◽  
Min Zhang ◽  
Changyan Sun

This manuscript reports the synthesis and fluorescent chemosensor property of a Schiff base derivative, 4-[(2-hydroxy-1-naphthyl) methylideneamino]benzoic acid (H2L). The fluorescence spectrum shows that H2L exhibits a highly selective and sensitive recognition for Al3+ ions in N,N′-dimethylformamide/water (DMF/H2O, 1/1, v/v). The fluorescence titration experiments and electrospray ionization mass spectrometry (ESI–MS) show that H2L and Al3+ ions form a 1:1 complex. 1H NMR titration results show that H2L coordinates to Al3+ ions with carboxylate, hydroxyl groups, and imine groups and the probable sensing mechanism may be the excited-state intramolecular proton transfer (ESIPT) process.


RSC Advances ◽  
2016 ◽  
Vol 6 (68) ◽  
pp. 63837-63847 ◽  
Author(s):  
Nayan Roy ◽  
Surjatapa Nath ◽  
Abhijit Dutta ◽  
Paritosh Mondal ◽  
Pradip C. Paul ◽  
...  

A new coumarin based Schiff-base chemosensor was synthesized and evaluated. Based on Job’s plot,1H NMR titration, ESI-MS and B-H plot, the structure of ligand and its metal ion is 1 : 1 stoichiometry. It also exhibits a binary logic function.


1998 ◽  
Vol 63 (3) ◽  
pp. 363-370 ◽  
Author(s):  
Violetta Patroniak-Krzyminiewska ◽  
Wanda Radecka-Paryzek

The template reactions of 2,6-diacetylpyridine with 3,6-dioxaoctane-1,8-diamine in the presence of dysprosium(III), thulium(III) and lutetium(III) chlorides and erbium(III) perchlorate produce the complexes of 15-membered macrocyclic ligand with an N3O2 set of donor atoms as a result of the [1+1] Schiff base cyclocondensation. In contrast, analogous reactions involving the lighter lanthanide ions (lanthanum(III), samarium(III) and europium(III)) yield the acyclic complexes with terminal acetylpyridyl groupings as products of the partial [2+1] condensation. The complexes were characterized by spectral data (IR, UV-VIS, 1H NMR, MS), and thermogravimetric and elemental analyses.


2021 ◽  
Vol 19 (1) ◽  
pp. 772-784
Author(s):  
Moamen S. Refat ◽  
Ahmed Gaber ◽  
Walaa F. Alsanie ◽  
Mohamed I. Kobeasy ◽  
Rozan Zakaria ◽  
...  

Abstract This article aimed at the synthesis and molecular docking assessment of new diimine Schiff base ligand, namely 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxyvinyl)hydrazono) methyl)-6-methoxyphenol (methoxy-diim), via the condensation of 1-(4-chloro-phenyl)-2-hydrazino-ethenol compound with 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxy vinyl) hydrazono)methyl)-6-methoxyphenol in acetic acid as well as the preparation of new binuclear complexes of Co(ii), Ni(ii), Cu(ii), and Zn(ii). The following synthesized complexes were prepared in a ratio of 2:1 (metal/ligand). The 1H-NMR, UV-Vis, and FTIR spectroscopic data; molar conductivity measurements; and microanalytical, XRD, TGA/DTG, and biological studies were carried out to determine the molecular structure of these complexes. According to the spectroscopic analysis, the two central metal ions were coordinated with the diamine ligand via the nitrogen of the hydrazine and oxygen of the hydroxyl groups for the first metal ions and via the nitrogen of the hydrazine and oxygen of the phenol group for the second metal ions. Molecular docking for the free ligand was carried out against the breast cancer 3hb5-oxidoreductase and the 4o1v-protein binding kidney cancer and COVID-19 protease, and good results were obtained.


1992 ◽  
Vol 267 (24) ◽  
pp. 16922-16927
Author(s):  
T Marti ◽  
H Otto ◽  
S.J. Rösselet ◽  
M.P. Heyn ◽  
H.G. Khorana
Keyword(s):  

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Lakhdar Sibous ◽  
Embarek Bentouhami ◽  
Mustayeen Ahmed Khan

4,4′-Diaminobiphenyl reacts with 2,4-pentanedione in absolute ethanol in a molar ratio 1 : 2 to form mainly the product of [1 + 2] condensation, 4,4′-(biphenyl-4,4′-diyldinitrilo)dipentan-2-one (H2L). The Schiff base was used as tetradentate chelating ligand to coordinate CoII and NiII chlorides leading to complexes where the ratio of metal ligand was found to be 2 : 1 or 2 : 2. All the synthesized products were characterized by elemental analysis, infrared, electronic, and mass spectroscopy, 1H NMR, and DSC. The electrochemical behaviour of the ligand and its complexes in DMF is also investigated.


RSC Advances ◽  
2015 ◽  
Vol 5 (81) ◽  
pp. 65731-65738 ◽  
Author(s):  
Divya Singhal ◽  
Neha Gupta ◽  
Ashok Kumar Singh

2-((3-Methylthiophen-2-yl)methyleneamino)benzenethiol (Probe 1) is selective for Hg2+. The binding affinity of Hg2+ with Probe 1 was confirmed by DFT and electrochemical behaviour. The limit of detection was 20 μM with 2 : 1 stoichiometry of 1 + Hg2+ complex.


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