ChemInform Abstract: PROTONATION KINETICS AND MECHANISM FOR 1,8‐DIHYDROXYANTHRAQUINONE AND ANTHRAQUINONE ANION RADICALS IN DIMETHYLFORMAMIDE SOLVENT

Wightman, R. Mark; Cockrell, John R.; Murray, Royce W.; Burnett, J. N.; Jones, Susan B.

doi:10.1002/chin.197628131

Cited by 1 publication

(2 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7. This is consistent with previously reported spectra of neutral AQ in DMF (31) and in an A1C13:BuPyC1 melt (1). Therefore, even in the presence of 6.5M HCI~, AQ is unprotonated.…”

Section: Cyclic Staircase Voltammetrysupporting

confidence: 93%

“…5A that the second wave is smaller than the first. Observation of the working electrode after removal from the melt following a long potential step to a value negative of the second reduction wave revealed that a red species was produced, indicative of the dianion, AQ 2- (31). The qualitative characteristics of the voltammetry in molten ImC1 are very similar to those observed by other workers in nonaqueous systems where no Lewis acid is available to react with the quinone anion radical and dianion (32,33).…”

Section: Cyclic Staircase Voltammetrysupporting

confidence: 78%

See 1 more Smart Citation

Interaction of 9, 10‐Anthraquinone with Tetrachloroaluminate and Proton in Basic Aluminum Chloride: 1‐ethyl‐3‐methylimidazolium Chloride Room‐Temperature Molten Salts

Carter

Osteryoung

1992

J. Electrochem. Soc.

View full text Add to dashboard Cite

The electrochemical behavior of 9, 10‐anthraquinone (AQ) in a basic room‐temperature molten salt composed of a mixture of AlCl3 and 1‐ethyl‐3‐methylimidazolium chloride false(normalImClfalse) is described. In the absence of a proton source, AQ is reduced via a quasireversible two‐electron transfer to AQfalse(AlCl3)2− . The homogeneous chemical steps coupled to the electron transfers are displacement of Cl− from AlCl4− to form AQfalse(AlCl3)22− . Addition of a proton source, imidazolium hydrogen dichloride false(ImHCl2false) , causes the coupled chemical reactions to shift from solvent leveling of reduced AQ by AlCl4− to more facile protonation steps. Visible spectroscopy of AQ in 0.8:1 melt and neat ImHCl2 show that AQ is present as the neutral, unprotonated quinone in its oxidized form. The two‐electron, two‐proton reduction product 9, 10‐dihydroxyanthracene false(AQH2false) is formed under these conditions but is unstable in the AlCl3:normalImCl melt. It is converted to AQfalse(AlCl3)22− , which is the reoxidizable form, regardless of whether protons are present in the melt. AQH2 is stable on the voltammetric time scale in neat ImHCl2 . Under these conditions, the hydroquinone is formed exclusively and the electrochemistry tends toward that of the classical 2 e−, 2 H+ case found in aqueous systems. Experiments in molten normalImCl , at 90°C, show that the quinone anion radical and dianion are stable only under conditions where no Lewis acid is available for adduct formation.

show abstract

“…7. This is consistent with previously reported spectra of neutral AQ in DMF (31) and in an A1C13:BuPyC1 melt (1). Therefore, even in the presence of 6.5M HCI~, AQ is unprotonated.…”

Section: Cyclic Staircase Voltammetrysupporting

confidence: 93%