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
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.
