On the Role of the Singlet-Oxygen Dimol Chemiluminescence in Dioxirane Reactions

Singlet-Oxygen Chemiluminescence in Peroxide Reactions

“…Rather high yields of 1 O 2 (Table ) have been recorded for the reaction of dioxiranes with nucleopilic anions (e.g., ca. 100% for the chloride ion). , The solvent influence on the Vis−CL emission provided additional support for the involvement of the 1 O 2 dimol species. , Thus, the CL intensity at λ > 600 nm for the reactions of DMD with the chloride ion in a water−acetone mixture is significantly lower than in halogenated solvents, , which is caused by the reduced singlet-oxygen lifetime in aqueous acetone . Likewise, the more than 2-fold decrease in the Vis−CL intensity a 700 nm (interference filter) found 99,133 for the reaction of the dioxirane with both the bromide and the chloride ions in a CCl 4 −acetone (1:1) or a CCl 4 −CH 2 Cl 2 (1:1) mixture, compared to pure carbon tetrachloride, is a consequence of the lower 1 O 2 lifetime in acetone and methylene chloride versus carbon tetrachloride.…”

“…The CL-enhancement effect by DABCO is, however, not general, since it was recently shown that DABCO efficiently quenches the CL of the dimol species, generated in the decomposition of 1,4-dimethylnaphthalene endoperoxide, in the ketone-catalyzed breakdown of KHSO 5 , as well as in the reaction of dioxiranes with tertiary amines and nucleophilic anions. These results 99 should caution us not to regard DABCO as a reliable probe for the detection of ( 1 O 2 ) 2 in peroxide-type chemiluminescent systems.…”

“…Moreover, no DMD decomposition and, consequently, no IR−CL of 1 O 2 is obtained for the nonnucleophilic pyridine and pyridine-type heteroarenes, whereas these amines still promote the decomposition of TFD with release of 1 O 2 (up to 5% yield). For the 4-dimethylaminopyridin- N -oxide, besides the IR emission at 1270 nm, visible CL of the singlet-oxygen dimol at 630 and 703 nm was recorded. , …”

“…In addition, the emission at 700 nm was recorded by means of interference filters. It was suggested, ,, however, that the emission at λ > 560 nm, as well as that at 700 nm, belongs to the singlet-oxygen dimol species.…”

“…Ketones such as acetone, butanone, and cyclohexanone catalyze efficiently the decomposition of the Caro acid and, consequently, enhance substantially the IR−CL intensity. , The acetone-catalyzed decomposition of Caro acid is also accompanied by the emission in the visible spectral region, with λ max at 633 and 703 nm due to the formation of the singlet-oxygen dimol (Scheme , path b).…”