McDermott, Sinead and Rooney, A. Denise and Breslin, Carmel B. (2012) Complexation study and spectrofluorometric determination of the binding constant for diquat and p-sulfonatocalix[4]arene. Tetrahedron, 60 (20). pp. 3815-3821. ISSN 0040-4020

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Abstract

The interactions between diquat (DQ) and p-sulfonatocalix[4]arene (C4S) were studied in an aqueous solution as a function of the ionic strength. Evidence for the formation of a complex between DQ and C4S was obtained using fluorescence measurements, while the stoichiometry of the complex was confirmed as 1:1 for DQ/C4S using UV–vis spectroscopy. The ionic strength had no influence on the stoichiometry of the complex, but exerted a significant influence on the complexation constant, Kc, decreasing with an increase in the ionic strength. The thermodynamic complexation constant, Kc′, was computed as 5.25±1.11×107 using the extended Debye–Hückel law. The rate constants for the heterogeneous electron transfer for the reduction of DQ at an electrode surface were evaluated as 0.150±0.010 cm s−1 in the absence of C4S and 0.065±0.010 cm s−1 when C4S was added to the solution in a 1:1 ratio.

Item Type:	Article
Keywords:	Diquat; p-Sulfonatocalix[4]arene; Ionic strength; Complexation constant;
Academic Unit:	Faculty of Science and Engineering > Chemistry
Item ID:	7812
Identification Number:	https://doi.org/10.1016/j.tet.2012.03.064
Depositing User:	Dr. Denise Rooney
Date Deposited:	25 Jan 2017 15:03
Journal or Publication Title:	Tetrahedron
Publisher:	Elsevier
Refereed:	Yes
Funders:	Science Foundation Ireland (SFI)
URI:	http://www.sciencedirect.com
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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