Chemistry of singlet oxygen with arylphosphines

Photoinduced oxidation of triphenylphosphine isolated in a low-temperature oxygen matrix

“…The three-membered ring peroxides with the form R 3 PO 2 , where the R group represents alkyl or aryl substituents, were reported to act as intermediates in reactions of singlet oxygen with organic phosphines in solutions and in the gaseous phase at room temperature and higher temperatures [1][2][3][4][30][31][32]. There has been much recent interest to such 'exotic peroxides' -to quote from the title of a recent review by Sawwan and Greer [33].…”

“…Recently, it has been reported that singlet molecular oxygen (generated photochemically with intermediacy of a photosensitizer) reacts with phosphines (1) in solutions at room temperature. In such reactions, the corresponding phosphine oxides (2) are generated as dominating products, whereas phosphinates (3) are produced only in very small amounts [1][2][3][4].…”

Photochemistry of Tris(2,4‐dibromophenyl)amine and its Application to Co‐oxidation on Sulfides and Phosphines†

“…Therefore, the ΔG 0 value is − 0.33 V for the case of triphenylphosphine and − 0.30 V for tris(o-tolyl)phosphine. The On the other hand, oxidation of triarylphosphines with singlet oxygen has been excluded as a competitive reaction pathway (path (c), Scheme 7), because it was found that the reaction between Ar 3 P Á+ and molecular oxygen displays a bimolecular rate constant k of 1.6 × 10 10 M −1 s −1 (38), which is higher than the rate constant between Ar 3 P and singlet oxygen (1.6 × 10 7 M −1 s −1 ) (39). Superoxide ion was also excluded as a possible oxidizing agent of the Ar 3 P Á+ since is involved as an electron carrier in the reduction of Ar 3 PO Á+ to triarylphosphine oxide (path (e)) as well as in the reduction of radical cation 1 Á+ the amine 1 through a back-electron transfer process.…”

Experimental and DFT Computational Insight into Nitrosamine Photochemistry—Oxygen Matters

“…Further studies could include the synthesis of 15 N-labeled nitrosamines so that structural elucidation of the peroxy intermediate by 15 N NMR spectroscopy is possible. Also, the creation of a “persistent” peroxy intermediate by stabilizing it kinetically with sterically hindered groups to shield the peroxide groups would be useful as has been done with dioxaphosphiranes − and carbonyl oxides that were otherwise difficult to characterize. Further studies could also focus on the peroxy intermediate and its implications in biological toxicity and environmental fate of nitrosamines.…”