Journal of Fluorescence

, Volume 25, Issue 6, pp 1867–1874 | Cite as

Influence of Solvent Polarizability on the Keto-Enol Equilibrium in 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol

  • Arkadiusz Matwijczuk
  • Andrzej Górecki
  • Daniel Kamiński
  • Beata Myśliwa-Kurdziel
  • Leszek Fiedor
  • Andrzej Niewiadomy
  • Grzegorz P. Karwasz
  • Mariusz Gagoś


This work presents spectroscopic studies of the keto–enol equilibrium induced by solvent polarizability in 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol a strong antiproliferative and anticancer thiadiazol derivative. Electronic absorption, steady state and time resolved fluorescence, and infrared spectroscopies were applied to investigate the keto and enol forms of this compound in a series of polar and non-polar solvents. The enol form dominates in polar solvents while, surprisingly, the keto form dominates in non-polar solvents with high average electric dipole polarizability e.g. n-alkenes. The electronic absorption spectrum of this derivative is more dependent on spatially averaged electric dipole polarizability of the solvent than on Kirkwood’s correlation or on Lorenz-Lorenz electric polarizability. By analogy of n-alkanes to the alkyl parts of lipids, one can expect that the transformation of 1,3,4-thiadiazoles to the keto form may be facilitated in the hydrophobic core of the lipid membrane. Such a transition may be of great practical importance for the design of biologically active pharmaceutics, which are able to interact with the hydrophobic regions of cell membranes in a specific manner.


1,3,4-thiadiazoles Intramolecular proton transfer Keto-enol tautomery Molecular spectroscopy 



This research was partly financed by the National Science Centre of Poland on the basis of decision no. DEC-2012/05/B/NZ1/00037 to MG, a grant from the University of Life Science in Lublin (TKF/MN/5 to AM), and a grant from the Foundation for Polish Science (TEAM/2010-5/3 to LF).


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Arkadiusz Matwijczuk
    • 1
    • 4
  • Andrzej Górecki
    • 3
  • Daniel Kamiński
    • 2
  • Beata Myśliwa-Kurdziel
    • 4
  • Leszek Fiedor
    • 4
  • Andrzej Niewiadomy
    • 2
  • Grzegorz P. Karwasz
    • 5
  • Mariusz Gagoś
    • 6
  1. 1.Department of BiophysicsUniversity of Life Sciences in LublinLublinPoland
  2. 2.Department of ChemistryUniversity of Life Sciences in LublinLublinPoland
  3. 3.Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and BiotechnologyJagiellonian UniversityKrakówPoland
  4. 4.Faculty of Biochemistry, Biophysics and BiotechnologyJagiellonian UniversityKrakówPoland
  5. 5.Aleksander Jabłoński Institute of PhysicsNicolaus Copernicus UniversityToruńPoland
  6. 6.Department of Cell Biology, Institute of Biology and BiochemistryMaria Curie-Skłodowska UniversityLublinPoland

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