title: Inclusion of Ethyl Acetoacetate Bearing 7-Hydroxycoumarin Dye by β-Cyclodextrin and its Cooperative Assembly with Mercury(II) Ions: Spectroscopic and Molecular Modeling Studies.
abstract: The inclusion of the fluorescent organic dye, ethyl 3-(7-hydroxy-2-oxo-2H-chromen-3-yl)-3-oxopropanoate (1) by the host β-cyclodextrin (β-CD), and its response toward mercuric ions (Hg2+), was studied by UV/Vis, fluorescence, and1H NMR spectroscopic analyses, mass spectrometry and molecular modeling studies.1H NMR measurements together with molecular modeling studies for dye 1 demonstrate that it exhibits two tautomeric forms (keto and enol); however, when the dye is included into the β-CD cavity, the enol form predominates. Moreover, by using spectroscopic and spectrometry techniques, a 1:1 stoichiometry was determined for the complexes formed between dye 1 (enol form) and β-CD, with a binding constant (Kb1=1.8×104m-1) and for the dye 1 (keto form)-Hg2+(Kb2=2.3×103m-1). Interestingly, in the presence of 1-β-CD complex and mercuric ions, a ternary supramolecular system (Hg-1-β-CD complex) was established, with a 1:1:1 stoichiometry and a Kb3value of 4.3×103m-1, with the keto form of the dye being the only one present in this assembly. The three-component system provides a starting point for the development of novel and directed supramolecular assemblies.
authors.affiliation: Facultad de Química, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, 6094411, Chile. mealiaga@uc.cl.
authors.forename: Margarita E
authors.initials: ME
authors.lastname: Aliaga
authors.affiliation: Facultad de Química, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, 6094411, Chile.
authors.forename: Angélica
authors.initials: A
authors.lastname: Fierro
authors.affiliation: Facultad de Química, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, 6094411, Chile.
authors.forename: Iván
authors.initials: I
authors.lastname: Uribe
authors.affiliation: Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago, C/ Jenaro de la Fuente s/n, Campus Vida, 15782, Santiago, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: García-Río
authors.affiliation: Facultad de Química, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago, 6094411, Chile. acanetem@uc.cl.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Cañete
mesh_terms: D000090:Acetoacetates / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D013058:Mass Spectrometry; D008628:Mercury / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D066244:Proton Magnetic Resonance Spectroscopy; D013056:Spectrophotometry, Ultraviolet; D014468:Umbelliferones / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D000090:Acetoacetates; D005456:Fluorescent Dyes; D007477:Ions; D014468:Umbelliferones; D047392:beta-Cyclodextrins; C031477:7-hydroxycoumarin; D008628:Mercury; C024840:ethyl acetoacetate; C031215:betadex
keywords: host-guest systems; mercury; molecular modeling; sensors; supramolecular chemistry