Stable radical cation from a diquaternary salt of 2,2′‐biquinoline

Dickeson, J. E.; Summers, L. A.

doi:10.1002/jhet.5570070226

Cited by 12 publications

(3 citation statements)

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“…At high pH 7a 2ϩ was unstable. 23 On addition of an excess amount of NaOD to a solution of 7a 2ϩ (MeSO 4 Ϫ ) 2 in D 2 O, the variation of the 1 H NMR spectrum showed that 7a 2ϩ was completely transformed to a new compound. Although the structure of this product was not determined, the 1 H and 13 C NMR spectra indicated inequivalence of the two quinoline groups, and it was likely to be an OH Ϫ adduct.…”

Section: Redox Behaviour Of Bq 2؉ Saltsmentioning

confidence: 99%

Chemiluminescence of 1,1′-biisoquinolinium and 2,2′-biquinolinium salts. Reactions of electron-rich olefins with molecular oxygen

Mori¹,

Isozaki²,

Maeda³

1997

J. Chem. Soc., Perkin Trans. 2

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2,2Ј-Dialkyl-1,1Ј-biisoquinolylidenes (BIQ), having been prepared by two-electron reduction of the corresponding diquaternary salts BIQ 2ϩ (X Ϫ ) 2 , react with triplet dioxygen to produce chemiluminescence (CL). In aprotic solvents, the kinetics of the reaction are first-order with respect to the concentrations of the substrate and of oxygen. The second-order rate constants at 25 ЊC increase in the order DMF < MeCN < DMSO, which correlate with the free energy change for an electron-transfer (ET) from BIQ to O 2 , although this process is endothermic in all three solvents. In non-polar solvents such as benzene, the reaction proceeds much more slowly. From these results, a reaction mechanism is proposed as follows. An ET or partial charge-transfer gives a radical ion pair {BIQ ϩ ؒ ؒ ؒ O 2 Ϫ } or a CT complex, in which intersystem crossing takes place from the triplet to the singlet state, and then radical coupling at the 1-position followed by cyclisation yields a 1,2-dioxetane, the postulated intermediate of the CL reaction. An electron-rich olefin having a closely related structure, 1,1Ј-dimethyl-2,2Ј-bisquinolylidene (BQ), shows a similar redox behaviour to that of BIQ. Reaction of BQ with O 2 produces CL, and the emitter has been identified as the singlet excited state of 1-methyl-2(1H)-quinolinone 8a. The effects of substituents in the quinoline ring on the autoxidation rate have been investigated in MeCN and DMSO. An olefin having the more negative oxidation potential shows the higher reactivity to O 2 , suggesting that the autoxidation of BQ should take place via a similar reaction pathway as that of BIQ.

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Section: Redox Behaviour Of Bq 2؉ Saltsmentioning

confidence: 99%

Chemiluminescence of 1,1′-biisoquinolinium and 2,2′-biquinolinium salts. Reactions of electron-rich olefins with molecular oxygen

Mori¹,

Isozaki²,

Maeda³

1997

J. Chem. Soc., Perkin Trans. 2

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“…A detailed study on the reduction of acetophenone including kinetics, adsorption, and the role of the solvent (777) and of the reduction and oxidation intermediates produced from acetophenone at a rotating disk electrode (482) was described. Acetophenone derivatives studied were -cyanoacetophenone as a function of pH and in the presence of proton donors (669), «-substituted acetophenones in DMF and acetonitrile (9), and aminoacetophenone derivatives as a function of pH (180).…”

Section: Aldehydesmentioning

confidence: 99%

“…Polarographic data were reported for 4-[fi-(pyridyl) vinyl ¡quinoline and its ethyl derivative as a function of pH (149), for 1,1'-dimethyl-2,2'-biquinolinium dimethsulfate (180), and for methiodides of quinoline, isoquinoline, 3,4-, 5,6-, 7,8-benzoquinoline, and 0-, m-, and p-phenanthroline derivatives (436)(437)(438). In the latter study, detailed electrochemical measurements were done and the data were correlated to Hueckel MO calculations.…”

Section: Nitrogen-containing Heterocyclic Compoundsmentioning

confidence: 99%