ELECTRON-TRANSFER PHOTOOXYGENATION OF TETRAPHENYLALLENE FORMATION OF 1,3-DIHYDROPEROXY-1,1,3,3-TETRAPHENYL-2-PROPANONE AND ITS DECOMPOSITION UNDER CHEMILUMINESCENCE

Article abstract of DOI:10.1016/S0040-4039(00)61872-5

DCA-sensitized electron-transfer photooxygenation of tetraphenylallene (1) in acetonitrile yields benzophenone (3) and polymeric material.In acetone, the yield of 3 is better than twice the amount obtained in acetonitrile and very little of polymeric material is observed.If the acetone solution is worked up immediately after the oxygen consumption ceased, 1,3-dihydroperoxy-1,1,3,3-tetraphenyl-2-propanone (8) is isolated.Its formation is proposed to occur via the peroxyallyl zwitterion 4 and the tetraphenylcyclopropanone (7) (Scheme 1). 8 decomposes slowly into 3, and CO+CO2 (3:1) in neutral solution; in the presence of a base, decomposition is fast, resulting in the formation of two molecules of 3, one molecule of water, and one molecule of CO2.Decomposition of 8 in the presence of various fluorescers and a base yields a bright fluorescence of the additives.