Photoinduzierte Elektronenübertragungsreaktionen zwischen aromatischen Diazoniumkationen und Anionen

Photoinduced Electron Transfer between Arenediazonium Cations and Anions Anions X^⊖ can act as donors in electron transfer reactions to photoexcited arenediazonium ions. The yield of the arene formed in this reaction increases with decreasing electrochemical oxidation potential E of X^⊖ (X^⊖ = BPh₄^⊖, Br^⊖, HOOC COO^⊖, Cl^⊖, BF₄^⊖). The oxidized donor X· (Cl·, ·COO^⊖) and aryl radicals Ar· benig intermediates of the reductive dediazoniation of ArN₂^⊖ can be detected by spin trapping with nitrosodurene (ND) and phenyl-tert-butylnitrone (PBN). A solvent effect in the electron transfer reaction is interpreted in terms of ion pairing, where the electron transfer is favored by preorientation and a short distance between the electron donor and the acceptor previous to excitation of ArN₂^⊖ by light.