Colorimetric recognition of anions using preorganized tetra-amidourea derived calix[4]arene sensors

Quinlan, E., Matthews, S. E. and Gunnlaugsson, T. (2007) Colorimetric recognition of anions using preorganized tetra-amidourea derived calix[4]arene sensors. The Journal of Organic Chemistry, 72 (20). pp. 7497-7503. ISSN 0022-3263

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Abstract

[GRAPHICS] The synthesis and the spectroscopic studies of the amidourea based calix[4]arene sensors I and 2 are described. The 4-nitrophenyl based sensor I was synthesized in two steps from the corresponding calix [4]arene tetraethyl ester and shown to give rise to color changes in the UV-vis spectra in DMSO upon recognition of pyrophosphate and fluoride. Fitting the changes in the absorption spectra using nonlinear regression analysis indicated strong binding of several anions by I such as acetate and hydrogen phosphate in 1: 1 (Host:Guest) stoichiometry, and at higher concentration in 1:2 stoichiometry. The preorganized calix-cavity was, however, not found to host chlorine while binding of bromide was determined. At high concentrations of these anions, significant colorimetric changes were also observed that were clearly visible to the naked eye for both pyrophosphate and fluoride. The phenyl analogue 2 was made to enable analysis of the anion recognition using H-1 NMR titrations and showed that ions such as phosphate were bound in 1:1 stoichiometry, whereas the "urea" protons were shown to be significantly affected upon coordination to the anion.

Item Type: Article
Uncontrolled Keywords: binding-sites,ternary complexes,aqueous-solution,photoinduced electron-transfer,chemosensors,pet sensors,bis-carboxylates,selective,charge neutral thiourea,molecular receptors,fluorescent
Faculty \ School: Faculty of Science > School of Pharmacy
Depositing User: Rachel Smith
Date Deposited: 26 May 2011 10:41
Last Modified: 31 Oct 2019 13:51
URI: https://ueaeprints.uea.ac.uk/id/eprint/31454
DOI: 10.1021/jo07O439a

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