Spectroscopic studies of inclusion complexation between ortho derivatives of p-methylaminobenzoate and α- and γ-cyclodextrins

Karolina Baranowska , Marek Józefowicz

Abstract

Using the steady-state and time-resolved spectroscopic techniques and quantum-chemical calculations, photophysical and photochemical properties of the two ortho derivatives of p-methylaminobenzoate (methyl o-methoxy p-methylaminobenzoate (I) and methyl o-hydroxy p-methylaminobenzoate (II)) have been studied in binary mixture THF-H2O and aqueous solutions containing different concentrations of α- and γ-CD. Nonlinear solvatochromic shifts of the absorption and fluorescence bands were observed for both fluorophores in a mixture of polar aprotic (THF) and polar protic (H2O) solvents. This nonlinearity has been explained in terms of the non-specific (dielectric enrichment of the solvent around the polar solute) and specific (hydrogen bond) solute-solvent interactions. Spectroscopic measurements were used to investigate the role of H-bonding solute-solvent interactions, and the excited-state intramolecular proton transfer process in the formation of inclusion complexes between fluorophore and cyclodextrins. The obtained results were used to calculate, according to Benesi–Hildebrand's plot and nonlinear least-squares regression analysis, equilibrium constants of the fluorophore-cyclodextrin inclusion complexes. Performed analysis indicates also that both 1:1 and 1:2 inclusion complexes were formed between studied compounds and α- and γ-cyclodextrins.
Author Karolina Baranowska (FMPI / IEP)
Karolina Baranowska,,
- Institute of Experimental Physics
, Marek Józefowicz (FMPI / IEP)
Marek Józefowicz,,
- Institute of Experimental Physics
Journal seriesJournal of Molecular Liquids, ISSN 0167-7322, (A 30 pkt)
Issue year2018
Vol265
Pages140-150
Publication size in sheets0.5
Keywords in Englishcyclodextrins, hydrogen bonding, excited-state intra molecular proton transfer, solute-solvent interactions
DOIDOI:10.1016/j.molliq.2018.05.120
URL https://doi.org/10.1016/j.molliq.2018.05.120
Languageen angielski
Score (nominal)30
ScoreMinisterial score = 30.0, 08-10-2018, ArticleFromJournal
Ministerial score (2013-2016) = 30.0, 08-10-2018, ArticleFromJournal
Publication indicators WoS Impact Factor: 2016 = 3.648 (2) - 2016=3.187 (5)
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