Spectroscopic and quantum chemical investigations of substituent effects on the azo-hydrazone tautomerism and acid-base properties of arylazo pyridone dyes
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2014
Authors
Dostanić, Jasmina
Mijin, Dušan

Ušćumlić, Gordana

Jovanović, Dušan M.
Zlatar, Matija

Lončarević, Davor

Article (Published version)

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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, H-1 NMR and C-13 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, pK(a), of the dyes was determined by UV-Vis spectroscopy and correlated with the Hammett substituent constants, sigma(p) and sigma(I). 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 (DET/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 d...yes with electron-donating and dyes with electron-withdrawing groups. The dependence of absorption spectra and determined pK(a) values to the substituent type seems to be mostly due to azo/hydrazone canonical structure ratio in their anionic form.
Keywords:
Azo dyes / Azo-hydrazone tautomerism / Absorption spectra / pK(a) / DFTSource:
Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy, 2014, 123, 37-45Publisher:
- Oxford : Pergamon-Elsevier Science Ltd
Funding / projects:
- Nanostructured Functional and Composite Materials in Catalytic and Sorption Processes (RS-45001)
- Study of the Synthesis, Structure and Activity of Natural and Synthetic Organic Compounds (RS-172013)
DOI: 10.1016/j.saa.2013.12.064
ISSN: 1386-1425
PubMed: 24388998
WoS: 000333777200007
Scopus: 2-s2.0-84891791908
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IHTMTY - JOUR AU - Dostanić, Jasmina AU - Mijin, Dušan AU - Ušćumlić, Gordana AU - Jovanović, Dušan M. AU - Zlatar, Matija AU - Lončarević, Davor PY - 2014 UR - https://cer.ihtm.bg.ac.rs/handle/123456789/1512 AB - 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, H-1 NMR and C-13 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, pK(a), of the dyes was determined by UV-Vis spectroscopy and correlated with the Hammett substituent constants, sigma(p) and sigma(I). 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 (DET/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 pK(a) values to the substituent type seems to be mostly due to azo/hydrazone canonical structure ratio in their anionic form. PB - Oxford : Pergamon-Elsevier Science Ltd T2 - Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy T1 - Spectroscopic and quantum chemical investigations of substituent effects on the azo-hydrazone tautomerism and acid-base properties of arylazo pyridone dyes VL - 123 SP - 37 EP - 45 DO - 10.1016/j.saa.2013.12.064 ER -
@article{ author = "Dostanić, Jasmina and Mijin, Dušan and Ušćumlić, Gordana and Jovanović, Dušan M. and Zlatar, Matija and Lončarević, Davor", year = "2014", 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, H-1 NMR and C-13 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, pK(a), of the dyes was determined by UV-Vis spectroscopy and correlated with the Hammett substituent constants, sigma(p) and sigma(I). 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 (DET/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 pK(a) values to the substituent type seems to be mostly due to azo/hydrazone canonical structure ratio in their anionic form.", publisher = "Oxford : Pergamon-Elsevier Science Ltd", journal = "Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy", title = "Spectroscopic and quantum chemical investigations of substituent effects on the azo-hydrazone tautomerism and acid-base properties of arylazo pyridone dyes", volume = "123", pages = "37-45", doi = "10.1016/j.saa.2013.12.064" }
Dostanić, J., Mijin, D., Ušćumlić, G., Jovanović, D. M., Zlatar, M.,& Lončarević, D.. (2014). Spectroscopic and quantum chemical investigations of substituent effects on the azo-hydrazone tautomerism and acid-base properties of arylazo pyridone dyes. in Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy Oxford : Pergamon-Elsevier Science Ltd., 123, 37-45. https://doi.org/10.1016/j.saa.2013.12.064
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. in Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy. 2014;123:37-45. doi:10.1016/j.saa.2013.12.064 .
Dostanić, Jasmina, Mijin, Dušan, Ušćumlić, Gordana, Jovanović, Dušan M., Zlatar, Matija, Lončarević, Davor, "Spectroscopic and quantum chemical investigations of substituent effects on the azo-hydrazone tautomerism and acid-base properties of arylazo pyridone dyes" in Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy, 123 (2014):37-45, https://doi.org/10.1016/j.saa.2013.12.064 . .