1
|
Ngororabanga JMV, Dembaremba TO, Mama N, Tshentu ZR. Azo-hydrazone tautomerism in a simple coumarin azo dye and its contribution to the naked-eye detection of Cu 2+ and other potential applications. Spectrochim Acta A Mol Biomol Spectrosc 2023; 289:122202. [PMID: 36521339 DOI: 10.1016/j.saa.2022.122202] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/02/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
A new tailor-made azo dye of coumarin connected to phenolic derivative is presented herein. Azo-hydrazone tautomerism in aqueous solution of the dye was observed and studied using spectroscopic assays such as 1H NMR, absorption and emission assays, and theoretical studies. Tautomerism was attributed to the presence of a labile phenolic hydrogen in the ortho position to the azo functionality and the hydrazone was found to be the more dominant tautomer. Influence of metal ions on the azo-hydrazone chemical equilibrium and how the accompanying colour and spectroscopic changes can be exploited for various functions, especially the detection and quantification of Cu2+ in aqueous environments was explored. The presence of Cu2+ affects the azo-hydrazone equilibrium resulting in visual appearance and spectroscopic changes and the likely binding sites for Cu2+ were evaluated. Cu2+ pushes the azo-hydrazone equilibrium towards the more conjugated form and the presence of other metal ions does not have any perceivable impact on this mechanism. The dye showed potential applications as a sensor in colorimetric and spectroscopic detection and quantification of Cu2+ in domestic and environmental water samples, photo-imprinting and as a logic gate. The limits of detection (LOD) and quantification (LOQ) for Cu2+ were found to be 0.0779 mg/L and 0.236 mg/L, respectively, much lower than the World Health Organization (WHO) guideline limit for Cu2+ levels in drinking water.
Collapse
Affiliation(s)
- Jean Marie Vianney Ngororabanga
- Department of Mathematics, Sciences and Physical Education, University of Rwanda College of Education, Po Box 55 Rwamagana-Eastern Province, Rwanda.
| | - Tendai O Dembaremba
- Department of Chemistry, Nelson Mandela University, Port Elizabeth 6031, South Africa
| | - Neliswa Mama
- Department of Chemistry, Nelson Mandela University, Port Elizabeth 6031, South Africa
| | - Zenixole R Tshentu
- Department of Chemistry, Nelson Mandela University, Port Elizabeth 6031, South Africa
| |
Collapse
|
2
|
Ölmez Nalcıoğlu Ö, Kılıç E, Haspulat Taymaz B, Kamış H. Synthesis of new azobenzo[c]cinnolines and investigation of electronic spectra and spectroelectrochemical behaviours. Spectrochim Acta A Mol Biomol Spectrosc 2021; 263:120175. [PMID: 34304013 DOI: 10.1016/j.saa.2021.120175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 06/13/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
A series of disazobenzo[c]cinnoline dyes was prepared by coupling reaction of 3,8-dihydroxybenzo[c]cinnoline with diazotised aromatic amines. The structures of these dyes were confirmed using UV-Vis, FTIR, 1H NMR, LC-MS/MS and LC-MS/TOF spectroscopic techniques. 13C NMR, 13C-DEPT, 1H-1H COSY, 1H-13C HMQC and 1H-13C HMBC spectra of dye 12 were demonstrated in this study. In addition, the effects of the substituent attached to the phenyl ring, solvent and acid-base on the UV-Vis spectra of the dyes were investigated. Besides, voltammetric and spectroelectrochemical behaviours of four disazobenzo[c]cinnolines (2, 8, 11 and 13) in acetonitrile (ACN) solution were also evaluated. It was observed that the disazobenzo[c]cinnoline derivatives indicated reversible voltammetric behaviour in acetonitrile-tetrabutylammonium perchlorate (ACN-TBAP) solution. A square-wave potential step method coupled with optical spectroscopy was used to probe switching times and optic contrast of the dyes.
Collapse
Affiliation(s)
- Öznur Ölmez Nalcıoğlu
- Department of Chemistry, Ankara University Faculty of Science, 06100 Ankara, Turkey; Department of Mathematics and Science Education, Science Education, Giresun University Faculty of Education, 28200 Giresun, Turkey.
| | - Emine Kılıç
- Department of Chemistry, Ankara University Faculty of Science, 06100 Ankara, Turkey.
| | - Bircan Haspulat Taymaz
- Department of Chemical Engineering, Konya Technical University Faculty of Engineering and Natural Sciences, 42250 Konya, Turkey.
| | - Handan Kamış
- Department of Chemical Engineering, Konya Technical University Faculty of Engineering and Natural Sciences, 42250 Konya, Turkey.
| |
Collapse
|
3
|
Ghanadzadeh Gilani A, Taghvaei V, Moradi Rufchahi E, Mirzaei M. Photo-physical and structural studies of some synthesized arylazoquinoline dyes. Spectrochim Acta A Mol Biomol Spectrosc 2017; 185:111-124. [PMID: 28551448 DOI: 10.1016/j.saa.2017.05.035] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/10/2017] [Accepted: 05/16/2017] [Indexed: 06/07/2023]
Abstract
This study presents the spectral and structure characteristics of seven azoquinoline dyes with different substituents and their new methylated counterparts for the first time, where some compounds are newly synthesized. The solvatochromic, tautomeric, halochromic, and dichroic behavior of the compounds were studied by electronic spectroscopy in various media. The different types of media were ordinary, multifunctional, and ordered liquids. The experiments were extended to include under acidic or basic conditions. The orientational behavior of the azo dye-doped liquid crystals was studied, and it was established that the azo form is the main species in high polar anisotropic media. The multi-parameter polarity scales were used to correlate the spectral data. Influence of acid and base on the absorption spectra of the dyes was also examined. Ionization constants for these dyes were determined in ethanol-water media. As a result, at the high dye concentrations, the intermolecular hydrogen bonding is more stable than the intra-molecular hydrogen bond, and therefore, the azo form is the main species in concentrated solutions. In order to provide more details, time-dependent density functional theory (TD-DFT) calculations were carried out for the representative models.
Collapse
Affiliation(s)
- A Ghanadzadeh Gilani
- Department of Chemistry, Faculty of Science, University of Guilan, Rasht, Iran; Department of Chemistry, University Campus 2, University of Guilan, Rasht, Iran.
| | - V Taghvaei
- Department of Chemistry, Faculty of Science, University of Guilan, Rasht, Iran; Department of Chemistry, University Campus 2, University of Guilan, Rasht, Iran
| | - E Moradi Rufchahi
- Department of Chemistry, Faculty of Science, Lahijan Branch, Islamic Azad University, Lahijan, Iran
| | - M Mirzaei
- Bioinformatics Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| |
Collapse
|
4
|
Debnath D, Roy S, Li BH, Lin CH, Misra TK. Synthesis, structure and study of azo-hydrazone tautomeric equilibrium of 1,3-dimethyl-5-(arylazo)-6-amino-uracil derivatives. Spectrochim Acta A Mol Biomol Spectrosc 2015; 140:185-197. [PMID: 25594208 DOI: 10.1016/j.saa.2014.12.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 12/05/2014] [Accepted: 12/09/2014] [Indexed: 06/04/2023]
Abstract
Azo dyes, 1,3-dimethyl-5-(arylazo)-6-aminouracil (aryl=-C6H5 (1), -p-CH3C6H4 (2), -p-ClC6H4 (3), -p-NO2C6H4 (4)) were prepared and characterized by UV-vis, FT-IR, 1H NMR, 13C NMR spectroscopic techniques and single crystal X-ray crystallographic analysis. In the light of spectroscopic analysis it evidences that of the tautomeric forms, the azo-enamine-keto (A) form is the predominant form in the solid state whereas in different solvents it is the hydrazone-imine-keto (B) form. The study also reveals that the hydrazone-imine-keto (B) form exists in an equilibrium mixture with its anionic form in various organic solvents. The solvatochromic and photophysical properties of the dyes in various solvents with different hydrogen bonding parameter were investigated. The dyes exhibit positive solvatochromic property on moving from polar protic to polar aprotic solvents. They are fluorescent active molecules and exhibit high intense fluorescent peak in some solvents like DMSO and DMF. It has been demonstrated that the anionic form of the hydrazone-imine form is responsible for the high intense fluorescent peak. In addition, the acid-base equilibrium in between neutral and anionic form of hydrazone-imine form in buffer solution of varying pH was investigated and evaluated the pKa values of the dyes by making the use of UV-vis spectroscopic methods. The determined acid dissociation constant (pKa) values increase according to the sequence of 2>1>3>4.
Collapse
Affiliation(s)
- Diptanu Debnath
- Department of Chemistry, National Institute of Technology, Agartala 799046, India
| | - Subhadip Roy
- Department of Chemistry, National Institute of Technology, Agartala 799046, India
| | - Bing-Han Li
- Department of Chemistry, Chung Yuan Christian University, Chung-Li 320, Taiwan
| | - Chia-Her Lin
- Department of Chemistry, Chung Yuan Christian University, Chung-Li 320, Taiwan
| | - Tarun Kumar Misra
- Department of Chemistry, National Institute of Technology, Agartala 799046, India.
| |
Collapse
|
5
|
Dostanić J, Mijin D, Ušćumlić G, Jovanović DM, Zlatar M, Lončarević D. Spectroscopic and quantum chemical investigations of substituent effects on the azo-hydrazone tautomerism and acid-base properties of arylazo pyridone dyes. Spectrochim Acta A Mol Biomol Spectrosc 2014; 123:37-45. [PMID: 24388998 DOI: 10.1016/j.saa.2013.12.064] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/02/2013] [Accepted: 12/08/2013] [Indexed: 06/03/2023]
Abstract
A series of 5-(4-substituted arylazo)-6-hydroxy-4-methyl-3-cyano-2-pyridone dyes was synthesized and the structure of the dyes was confirmed by UV-Vis, FT-IR, (1)H NMR and (13)C NMR spectroscopic techniques. The azo-hydrazone tautomeric equilibrium was found to depend on the substituents as well as on the acidity and basicity of the media. Ionization constant, pKa, of the dyes was determined by UV-Vis spectroscopy and correlated with the Hammett substituent constants, σp and σI. The interpretation of the effect of different substituent in phenyl ring of arylazo pyridone dyes on their spectroscopic and structural properties was based on quantum chemical calculations performed by the density functional theory (DFT/M06-2X) method. The DFT calculations confirmed the existence of two forms in water solution: hydrazone form in acidic and neutral media and anionic form in basic media. The different contribution of azo and hydrazone canonical forms of anionic form is observed for dyes with electron-donating and dyes with electron-withdrawing groups. The dependence of absorption spectra and determined pKa values to the substituent type seems to be mostly due to azo/hydrazone canonical structure ratio in their anionic form.
Collapse
Affiliation(s)
- J Dostanić
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade, Serbia.
| | - D Mijin
- Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
| | - G Ušćumlić
- Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
| | - D M Jovanović
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade, Serbia
| | - M Zlatar
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Chemistry, Njegoševa 12, 11000 Belgrade, Serbia
| | - D Lončarević
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade, Serbia
| |
Collapse
|