|
Reduction and Oxidation of Hydroxyquinolines in Acetonitrile and Dimethylsulfoxide
Sokolová, Romana ; Ramešová, Šárka ; Fiedler, Jan ; Kolivoška, Viliam ; Degano, I. ; Gál, M. ; Szala, M. ; Nycz, J. E.
This study is focused on investigation of oxidation and reduction pathways of selected hydroxyquinoline compounds in nonaqueous solutions. The experimentally obtained reduction potentials are reported to well correlate with calculated values of LUMO energies as well as the obtained oxidation potentials are in a good agreement with theoretical HOMO energies. The cyclic voltammetry, in situ UV/Vis spectroelectrochemistry and in situ IR spectroelectrochemistry confirmed that the oxidation mechanism is complicated. Oxidation unexpectedly proceeds together with protonation of the starting compound. This behaviour was found for all studied compounds, hydroxyquinoline carboxylic acids and also for compounds, where a methyl group is present instead of carboxylic group.
|
|
Electrochemical Study of Rhamnazin
Ramešová, Šárka ; Sokolová, Romana ; Degano, I.
The natural flavonoid compound rhamanzin (3,5,4’-trihydroxy-7,3’-dimethoxyflavone) is important bioactive compound with antioxidative, anti-allergic, and anti-inflammatory properties. The cyclic voltammetry is used for the electrochemistry behavior of rhamnazin. The determination of oxidation pathways is supported by the identification of degradation products using separation technique.
|
|
The Electrochemistry of Natural Pigments
Sokolová, Romana ; Degano, I. ; Hromadová, Magdaléna ; Pospíšil, Lubomír
The electrochemical properties of flavonoid compounds (hemotoxylin, quercetin) were studied in buffered aqueous and non-aqueous solutions. The role of the preceding protonation/deprotonation on the electron transfer was estimated. The absorption spectra of these compounds, which contain a chromophore, were recorded during their oxidation. The electrochemical techniques were combined with GC-MS analysis in order to identify the degradation products. The mechanism of the formation of degradation products will be discussed.
|
| |