Journal article
+ 1 other files
Tautomerism in azo dyes: Border cases of azo and hydrazo tautomers as possible NMR reference compounds
-
Deneva, Vera
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
-
Lyčka, Antonin
Faculty of Science, University of Hradec Králové, Czech Republic
-
Hristova, S.
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
-
Crochet, Aurélien
Department of Chemistry, University of Fribourg, Switzerland
-
Fromm, Katharina M.
Department of Chemistry, University of Fribourg, Switzerland
-
Antonov, Liudmil
Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
Show more…
Published in:
- Dyes and Pigments. - 2019, vol. 165, p. 157–163
English
In order to meet the need for NMR reference compounds in the study of tautomeric azo dyes, two series of azo dyes, derived from 3-methyl-1-phenyl-4- (phenyldiazenyl)-1H-pyrazol-5-amine and 5-methyl-2-phenyl-4-(2- phenylhydrazono)-2,4-dihydro-3H-pyrazol-3-one, have been studied by using molecular spectroscopy (UV–Vis and NMR) and quantum-chemical calculations (M06- 2X/TZVP) in solution. The results clearly indicate that 3-methyl-1-phenyl-4- (phenyldiazenyl)-1H-pyrazol-5-amines are present in pure azo tautomeric form, while 5-methyl-2-phenyl-4-(2-phenylhydrazono)-2,4-dihydro-3H-pyrazol-3-ones exist as hydrazone tautomers. The tautomeric state is not substantially influenced by nitro group substitution in the phenyl ring. Consequently, the studied compounds can be used as model tautomers in the NMR evaluation of the tautomeric state in various azo dyes in solution. According to the crystallographic data (obtained by us or available in the literature) the conclusions about the tautomerism of the studied compounds in solution are valid in solid state as well.
-
Faculty
- Faculté des sciences et de médecine
-
Department
- Département de Chimie
-
Language
-
-
Classification
-
Chemistry
-
License
-
License undefined
-
Identifiers
-
-
Persistent URL
-
https://folia.unifr.ch/unifr/documents/307936
Other files
Statistics
Document views: 40
File downloads:
- fro_tad.pdf: 263
- fro_tad_sm.pdf: 69