Electron-transfer rates through zinc porphyrin multilayers films on gold electrodes
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Authors
Robinson, Naomi R.
Issue Date
2020-05
Type
Electronic thesis
Thesis
Thesis
Language
ENG
Keywords
Chemistry
Alternative Title
Abstract
Zn(II) 5,10,15,20-tetra(4-ethynylphenyl)porphyrin (ZnTPEP) was used to fabricate multilayered films, using either 1,3,5-tris(azidomethyl)benzene (N3-Mes) and 1,4 bis(azidomethyl)benzene (N3-Xyl) as linkers, by through a layer-by-layer (LbL) assembly technique utilizing copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions. Bilayer growth was tracked using UV-Visible specular reflectance, and electrochemistry was performed on these films to determine through-film electron-transfer rates. The chronoamperometric data was analyzed using the Butler-Volmer (B-V) formalism to determine the overall electron-transfer rates (kET), the standard electron-transfer rates (ko), and the self-exchange electron-transfer rates (kse) for varying bilayers of ZnTPEP with the two linkers. ZnTPEP with N3-Mes was found to have better bilayer growth and lower rate constants as compared to ZnTPEP with N3-Xyl. The self-exchange rate constant was shown to have a greater contribution to the overall electron-transfer rate than the standard rate constant. Spectroelectrochemistry (SEC) of the multilayer structures confirmed electrochemical reversibility of the ZnTPEP oxidation. Electrochemical rectification studies using ethynylferrocene provided evidence of uniform multilayer structures.
Description
May 2020
School of Science
School of Science
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY