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Switching azonaphthols containing a side chain with limited flexibility. Part 1. Synthesis and tautomeric properties

  • Kurteva, Vanya B. Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
  • Antonov, Liudmil Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
  • Nedeltcheva, Daniela V. Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
  • Crochet, Aurélien University of Fribourg, Department of Chemistry, Switzerland
  • Fromm, Katharina M. University of Fribourg, Department of Chemistry, Switzerland
  • Nikolova, Rositsa P. Institute of Mineralogy and Crystallography “Acad. Ivan Kostov”, Bulgarian Academy of Sciences, Sofia, Bulgaria
  • Shivachev, Boris L. Institute of Mineralogy and Crystallography “Acad. Ivan Kostov”, Bulgarian Academy of Sciences, Sofia, Bulgaria
  • Nikiforova, Maya S. Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
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    08.08.2011
Published in:
  • Dyes and Pigments. - 2012, vol. 92, no. 3, p. 1266–1277
Azonaphthol dyes
Rigid side chain
Preferred conformations
Quantum chemical calculations
Spectroscopy
X ray
English A series of azo dyes, possessing amide fragments with restricted flexibility tethered to 4-(phenyldiazenyl)naphthalen-1-ol, was obtained from 1-hydroxy-2-naphthoic acid by subsequent conversion to amides and diazo coupling. It was shown that the position of the tautomeric equilibrium in solution strongly depends on the solvent in both UV and NMR concentration scale. The compounds exist as pure enol forms in chloroform and hydrocarbons, while in polar solvents (acetone, acetonitrile, alcohols) a tautomeric mixture is observed. According to the quantum-chemical calculations the aggregation of the keto tautomer is the possible reason for this shift in the position of the tautomeric equilibrium. To support the theoretical predictions, it was found that from acetone the keto form crystallizes as a dimer with hydrogen bonding between N1–H in the one molecule and amide Cdouble bond; length as m-dashO in the other forming a three-dimensional structure. The importance of the side-chain nitrogen atom on the dimer formation was confirmed by solution and solid state study of 4- (phenyldiazenyl)-2-acetylnaphthalen-1-ol. The results indicate that the new azo-dyes obtained could be suitable candidates for switching and sensing applications in non- polar solvents.
Faculty
Faculté des sciences et de médecine
Department
Département de Chimie
Language
  • English
Classification
Chemistry
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/302360
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