title: 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.
abstract: 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.
authors.affiliation: Department of Biophysics, University of Life Sciences in Lublin, 20-950, Lublin, Poland. arekmatwijczuk@gmail.com.|Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland. arekmatwijczuk@gmail.com.
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Matwijczuk
authors.affiliation: Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Górecki
authors.affiliation: Department of Chemistry, University of Life Sciences in Lublin, 20-950, Lublin, Poland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kamiński
authors.affiliation: Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Myśliwa-Kurdziel
authors.affiliation: Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
authors.forename: Leszek
authors.initials: L
authors.lastname: Fiedor
authors.affiliation: Department of Chemistry, University of Life Sciences in Lublin, 20-950, Lublin, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Niewiadomy
authors.affiliation: Aleksander Jabłoński Institute of Physics, Nicolaus Copernicus University, 87-100, Toruń, Poland.
authors.forename: Grzegorz P
authors.initials: GP
authors.lastname: Karwasz
authors.affiliation: Department of Cell Biology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, 20-033, Lublin, Poland. mariusz.gagos@poczta.umcs.lublin.pl.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Gagoś
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D007536:Isomerism; D012118:Resorcinols / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013830:Thiadiazoles / Q000737:chemistry*
chemical_list: C000610107:4-(5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl)benzene-1,3-diol; D000475:Alkenes; D012118:Resorcinols; D012997:Solvents; D013830:Thiadiazoles
keywords: 1,3,4-thiadiazoles; Intramolecular proton transfer; Keto-enol tautomery; Molecular spectroscopy