Tautomerism and Self-Association in the Solution of New Pinene-Bipyridine and Pinene-Phenanthroline Derivatives

Atena  B. Solea; Ivan Cornu; Vera Deneva; Aurelien Crochet; Katharina  M. Fromm; Liudmil Antonov; Christophe Allemann; Olimpia Mamula

doi:10.3390/molecules25020298

Molecules (Jan 2020)

Tautomerism and Self-Association in the Solution of New Pinene-Bipyridine and Pinene-Phenanthroline Derivatives

Atena B. Solea,
Ivan Cornu,
Vera Deneva,
Aurelien Crochet,
Katharina M. Fromm,
Liudmil Antonov,
Christophe Allemann,
Olimpia Mamula

Affiliations

Atena B. Solea: Haute Ecole d’Ingénierie et d’Architecture Fribourg, HES-SO University of Applied Sciences of Western Switzerland, Pérolles 80, CH-1705 Fribourg, Switzerland
Ivan Cornu: Haute Ecole d’Ingénierie et d’Architecture Fribourg, HES-SO University of Applied Sciences of Western Switzerland, Pérolles 80, CH-1705 Fribourg, Switzerland
Vera Deneva: Bulgarian Academy of Sciences, Institute of Organic Chemistry with Centre of Phytochemistry, Acad. G. Bonchev street, bl. 9, 1113 Sofia, Bulgaria
Aurelien Crochet: Haute Ecole d’Ingénierie et d’Architecture Fribourg, HES-SO University of Applied Sciences of Western Switzerland, Pérolles 80, CH-1705 Fribourg, Switzerland
Katharina M. Fromm: Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland
Liudmil Antonov: Bulgarian Academy of Sciences, Institute of Organic Chemistry with Centre of Phytochemistry, Acad. G. Bonchev street, bl. 9, 1113 Sofia, Bulgaria
Christophe Allemann: Haute Ecole d’Ingénierie et d’Architecture Fribourg, HES-SO University of Applied Sciences of Western Switzerland, Pérolles 80, CH-1705 Fribourg, Switzerland
Olimpia Mamula: Haute Ecole d’Ingénierie et d’Architecture Fribourg, HES-SO University of Applied Sciences of Western Switzerland, Pérolles 80, CH-1705 Fribourg, Switzerland

DOI: https://doi.org/10.3390/molecules25020298
Journal volume & issue: Vol. 25, no. 2
p. 298

Abstract

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Two novel pinene-type ligands have been synthesized and their tautomeric and self-associating behavior studied in solution and in the solid state. The first ligand, an acetylated derivative of 5,6-pinene-bipyridine, displays keto-enol tautomerism in solution. This tautomeric equilibrium was studied by NMR and UV-Vis spectroscopy in various solvents, and the results were compared with the ones obtained through DFT calculations. The second ligand was obtained by an unusual oxidation of the phenanthroline unit of a pinene-phenanthroline derivative. This compound exists as a single tautomer in solution and aggregates both in solution (as observed by NMR) and in the solid state through H-bonding as observed by X-ray structure determination and confirmed by DFT studies.

Published in Molecules

ISSN: 1420-3049 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Chemistry: Organic chemistry
Website: http://www.mdpi.com/journal/molecules

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