10-hydroxybenzo[h]quinoline: Switching between single and double-well proton transfer through structural modifications

S Hristova, G Dobrikov, F. S. Kamounah, S Kawauchi, Poul Erik Hansen, V Deneva, D Nedelcheva, L Antonov

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Proton transfer in 10-hydroxybenzo[h]quinoline (HBQ) and structurally modified compounds was investigated experimentally (steady state UV-Vis absorption and emission spectroscopy, NMR and advanced chemometric techniques) and theoretically (DFT and TD-DFT M06-2X/TZVP calculations) in the ground and excited singlet state. We observed that the incorporation of electron acceptor substituents on position 7 of the HBQ backbone led to appearance of a keto tautomer in ground state and changes in the excited state potential energy surface. Both processes were strongly solvent dependent. In the ground state the equilibrium could be driven from the enol to the keto form by change of solvent. The theoretical calculations explain the substitution-determined transition from a single- to a double-well proton transfer mechanism
Original languageEnglish
JournalRSC Advances
ISSN2046-2069
DOIs
Publication statusPublished - 2015

Keywords

  • tautomerism
  • ESIPT
  • DFT
  • TD-DFT callculations
  • NMR
  • UV-VIS

Cite this