Anodic oxidation of selenadiazoloquinolones in alkaline media.
Newly synthesized derivatives of 6-oxo-6,9-dihydro[1,2,5]selenadiazolo[3,4-h]quinoline variously substituted at position 7 (R = H, COOH, COCH(3), CN, COOC(2)H(5) and COOCH(3)) are established in strongly alkaline aqueous solutions (0.1 M NaOH; pH ∼ 13) as N(9)-deprotonated structures, but in less alkaline solutions (0.001 M NaOH; pH ∼ 11) the N(9)-protonated oxo tautomeric forms dominate. Upon their anodic oxidation in alkaline solutions, the selenadiazole ring is replaced, forming instead the paramagnetic species analogous to the ortho semiquinone radical anions as monitored by in situ EPR spectroscopy. The quantum chemical calculations for two representative selenadiazoloquinolones (R = H and COOH) and their anodic oxidation products presented are in agreement with experiments.
Faculty of Chemical and Food Technology, Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic.
Andrej
A
Staško
Michal
M
Zalibera
Zuzana
Z
Barbieriková
Ján
J
Rimarčík
Vladimír
V
Lukeš
Maroš
M
Bella
Viktor
V
Milata
Vlasta
V
Brezová
D004566:Electrodes; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D011789:Quantum Theory; D011804:Quinolines / Q000737:chemistry*; D012643:Selenium / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry*; D012996:Solutions
D009942:Organometallic Compounds; D011804:Quinolines; D012996:Solutions; D012972:Sodium Hydroxide; D012643:Selenium