6000-10-8Relevant articles and documents
cis-trans Isomerization of 1,2-Bis(4-metoxyphenyl)cyclopropanes via a Cationic Chain Mechanism
Toki, Susumu,Komitsu, Shintaro,Tojo, Sachiko,Takamuku, Setsuo,Ichinose, Nobuyuki,et al.
, p. 433 - 436 (1988)
Radiation-induced cis-trans isomerization of 1,2-bis(4-metoxyphenyl)cyclopropanes(CP) has been investigated in benzonitrile solution.The isomerization from cis-CP to trans-CP proceeded efficiently ( G = 80 ) via a cationic chain mechanism.Three types of t
Cyclopropanation with gold(I) carbenes by retro-Buchner reaction from cycloheptatrienes
Solorio-Alvarado, César R.,Wang, Yahui,Echavarren, Antonio M.
, p. 11952 - 11955 (2011/10/04)
Cationic gold(I) promotes the retro-Buchner reaction of 7-substituted 1,3,5-cycloheptatrienes, leading to gold(I) carbenes that cyclopropanate alkenes.
Generation of Polyphenylene Radical Cations and Their Cosensitization Ability in the 9,10-Dicyanoanthracene-Sensitized Photochemical Chain Reactions of 1,2-Bis(4-methoxyphenyl)cyclopropane
Tamai, Toshiyuki,Ichinose, Nobuyuki,Tanaka, Tomoko,Sasuga, Tsuneo,Hashida, Isao,Mizuno, Kazuhiko
, p. 3204 - 3212 (2007/10/03)
Cosensitization effects of polyphenylene compounds (PP) such as biphenyl (BP), terphenyls (o-, m-, p-TP), and phenanthrene (Phen) in photoinduced electron-transfer reactions were examined. The 9,10-dicyanoanthracene (DCA)-sensitized cis-trans photoisomerization of 1,2-bis(4-methoxyphenyl)-cyclopropane (CP), which proceeds in a chain reaction via free radical cation of CP (CP.+) as a chain carrier, was accelerated by adding PP, particularly by TP. A similar accelerating effect was observed in the DCA-sensitized photooxygenation of CP as another example. BP and TP were more stable under the oxygenation condition than phenanthrene and naphthalene, which also accelerate the photooxygenation CP. CP.+ is generated by the direct electron transfer from CP to the excited singlet state of DCA (1DCA*) and also by the secondary electron transfer from CP to PP.+, which is generated by the primary electron transfer from PP to 1DCA*. The laser flash photolysis study revealed that the quantum yield for the formation of free CP.+ in the direct electron transfer from CP to 1DCA* (ΦCP.+ ≈ 0.1) was smaller than that in the presence of PP. This is due to the high yield of free PP.+ generation by the primary electron transfer and the efficient secondary electron transfer from CP to PP.+. The secondary electron transfers were found to take place in nearly diffusion-controlled rates (0.9-1.5 × 1010 M-1 s-1). The high yield of PP.+ as free radical ions does not seem to be the sole factor of the cosensitization of PP for the DCA-sensitized photoreactions of CP. The ratio of the quantum yields of the photoreactions to that of the initial CP.+ formation (turnover) also increased by the addition of PP from 3 (isomerization) and 15 (oxygenation) to 32-90 for both reactions. The second-order rate constant for the decay of CP.+ in aerated acetonitrile was decreased by a factor of 0.5-0.8 by the addition of PP. We concluded that the cosensitization effect in the photoreaction involves a π-complex formation between CP.+ and PP assisting the chain reaction as well as initial CP.+ formation.