Application of electron spin resonance spectroscopy to studies of valence isomerization. III. Aliphatic semidiones. XXVII. Radical anions derived from bicyclo[4.n.0]alk-3-ene-2,5-diones

“…EPR analysis of a 0.018 M solution of R -camphorquinone reduced with sodium tert- butoxide in S , S -(+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane ( SS -DDB) yields the well-resolved EPR spectrum previously observed in dimethyl sulfoxide . The addition of the NaI to the anion radical solution results in broadening of the hyperfine components owing to the rapid formation and dissociation of ion-associated semidiones, reaction 1.…”

Section: Resultsmentioning

confidence: 99%

EPR Chiral Discrimination ofR- andS-Anion Radicals

1998

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Electron paramagnetic resonance spectroscopy has been used to discriminate between the R- and S-forms of the anion radical of camphorquinone. In a chiral solvent [SS- or RR-2,3-dimethoxy-1,4-bis(dimethylamino)butane saturated with sodium iodide], ion association between the semidione and Na+ takes place. PM3 calculations suggest that the complex relationship between the solvent, anion, and cation varies sufficiently with changes in the chiral nature of the solvent or anion radical to alter the appearance of the EPR signal allowing EPR chiral discrimination.

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“…[32] Accordingly, the detection of DMSO · and its decay has not been addressed in previous studies. [29][30][31][32] The reaction mechanism for electron transfer from DMF -to unsaturated compounds is probably not less ambiguous. [20] Whatever reservations can be forwarded on the electron-transfer mechanism from DMSO -and DMF -, Car (1) undeniably takes up electrons and is reduced to give the blue dianion Car 2-(3) (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

“…The presented method of generating dienolate anions by electron transfer to α,ω-polyene aldeydes refers to related prior research on generating anion radicals by single electron transfer to (un)-saturated mono or vicinal diketones. [29][30][31][32] Several oxocarotenoids have been exploratorily tested in alkaline DMSO and DMF. In this paper we concentrate to exemplify the reaction with 1 (Scheme 1).…”

Section: ·-mentioning

confidence: 99%