Publication Type Journal Article
Title Bidentate Urea Derivatives of p-tert-Butyldihomooxacalix[4]arene: Neutral Receptors for Anion Complexation
Authors Paula M. Marcos Filipa A. Teixeira Manuel A. P. Segurado José do Rosário Ascenso Raul J. Bernardino Sylvia Michel Veronique Hubscher-Bruder
Groups BioMol
Journal JOURNAL OF ORGANIC CHEMISTRY
Year 2014
Month January
Volume 79
Number 2
Pages 742-751
Abstract Three new bidentate ureidodihomooxacalix[4]arene derivatives (phenyl 5a, n-propyl 5b, and tert-butyl 5c) were synthesized in four steps from the parent compound p-tert-butyldihomooxacalix[4]arene and obtained in the cone conformation, as shown by NMR studies. The binding ability of these neutral receptors toward spherical, linear, trigonal planar, and tetrahedrical anions was assessed by H-1 NMR and UV-vis titrations. The structures and complexation energies of some complexes were also studied by DFT methods. The data showed that the association constants are strongly dependent on the nature of the substituent (aryl/alkyl) at the urea moiety. In general, for all the receptors, the association constants decrease with decrease of anion basicity. Ph-urea 5a is the best anion receptor, showing the strongest complexation for F- (log K-assoc = 3.10 in CDCl3) and also high binding affinity for the carboxylates AcO- and BzO(-). Similar results were obtained by UV-vis studies and were also corroborated by DFT calculations.
DOI http://dx.doi.org/10.1021/jo4026012
ISBN
Publisher AMER CHEMICAL SOC
Book Title
ISSN 0022-3263
EISSN
Conference Name
Bibtex ID ISI:000330099000027
Observations
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