123726-17-0Relevant articles and documents
Comparison of the Photochemistry of Diarylchloronium, Diarylbromonium, and Diaryliodonium Salts
Dektar, John L.,Hacker, Nigel P.
, p. 1838 - 1844 (2007/10/02)
The direct and triplet-sensitized photochemistry of diphenylchloronium, diphenylbromonium, bis(4-methylphenyl)chloronium, and bis(4-methylphenyl)bromonium salts was studied.Direct photolysis of the diarylhalonium salts gave haloarene, 2-, 3-, and 4-halobiaryls, and acetanilide, predominantly from a heterolytic cleavage mechanism via the aryl cation-haloarene pair, via in-cage recombination and cage-escape reactions.However, triplet-sensitized photolysis gave haloarene, 2-, 3-, and 4-halobiaryl, and reduced arene mainly from homolytic cleavage to the arene radical-haloarene radical cation pair, which also gave in-cage recombination and cage-escape products.There is evidence for singlet-triplet interconversion of the excited states by spin-orbit coupling and interconversion of the singlet-triplet radical pairs by spin-spin coupling.In addition, electron transfer between the singlet arene cation-haloarene and arene radical-haloarene radical cation pairs is also possible.The effect of halogen and arene substituent on these interconversions is discussed.
Photochemistry of Diaryliodonium Salts
Dektar, John L.,Hacker, Nigel P.
, p. 639 - 647 (2007/10/02)
The photochemistry of diphenyl- and bis(4-methylphenyl)iodonium salts was investigated by product analysis, measurement of acid, and determination of the consumption of the iodonium salts.The primary products formed upon direct and triplet-sensitized irradiation of diphenyliodonium salts are iodobenzene, 2-, 3-, and 4-iodobiphenyl, acetanilide, benzene, and acid.Similarly, iodotoluene, iodobitolyls, 4-methylacetanilide, toluene, and acid are formed from photolysis of bis(4-methylphenyl)iodonium salts.The photolysis products are formed by heterolysis of the diaryliodonium salt to phenyl cation and iodobenzene and also by homolysis to phenyl radical and iodobenzene radical cation.Direct photolysis favors product formation by the heterolytic cleavage pathway, whereas triplet sensitization gives more product from homolytic cleavage.Interconversion between phenyl cation pair and the phenyl radical pair can occur by an electron transfer.Sensitized photodecomposition of the iodoniumsalts by anthracene gives iodoarene and arylated anthracenes by an electron-transfer mechanism.Electron-transfer quenching and triplet quenching by the iodonium salt are competitive reactions for some sensitizers.The similarities and differences between diaryliodonium and triarylsulfonium photochemistry will be described.
