Hendy, Gillian M. and Breslin, Carmel B.
(2012)
An electrochemical study in aqueous solutions on the binding of dopamine to a sulfonated cyclodextrin host.
Electrochimica Acta, 59 (1).
pp. 290-2953.
ISSN 0013-4686
Abstract
Clear evidence for the formation of a weak inclusion complex between dopamine (DA) and a sulfonated β-CD host in aqueous solution was obtained using a combination of electrochemical approaches. Using cyclic voltammetry, a distinct increase in the oxidation potential of DA and a reduction in the peak oxidation current were observed on adding an excess concentration of the sulfonated β-CD to the electrolyte solution. Equally, a clear increase in the half-wave oxidation potential of DA was observed in the presence of the sulfonated β-CD using rotating disc voltammetry. The association constant, K, was computed as 331.3 ± 5.8, indicating the formation of a weak inclusion complex, while a 1:1 stoichiometry for the inclusion complex was deduced from a Job's plot analysis. The rate constant for the oxidation of DA was found to decrease on formation of the inclusion complex. This was attributed to higher reorganization energy for the oxidation of the included DA. These changes in the electrochemistry of DA were not observed when an excess of the smaller sulfonated α-CD was added to the electrolyte, indicating that these variations are not connected with simple electrostatic interactions between the protonated DA and the anionic sulfonated groups. It is proposed that the aromatic ring of the DA molecule includes within the cyclodextrin cavity, while the protonated amine group remains outside the cavity, bound electrostatically with the anionic sulfonated groups.
| Item Type: |
Article
|
| Keywords: |
Inclusion complex; β-Cyclodextrin; Dopamine; Association constant; |
| Academic Unit: |
Faculty of Science and Engineering > Chemistry |
| Item ID: |
7900 |
| Identification Number: |
https://doi.org/10.1016/j.electacta.2011.10.059 |
| Depositing User: |
Dr. Carmel Breslin
|
| Date Deposited: |
10 Feb 2017 17:13 |
| Journal or Publication Title: |
Electrochimica Acta |
| Publisher: |
Elsevier B.V. |
| Refereed: |
Yes |
| Funders: |
Irish Research Council for Science Engineering and Technology (IRCSET), John and Pat Hume Scholarship |
| URI: |
|
| 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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