124576-73-4Relevant academic research and scientific papers
Charge-density and ring-size dependent dimerization of 1-arylcycloalkene cation radicals
Kojima, Masanobu,Ishida, Akito,Kuriyama, Yasunao,Oishi, Shigero
, p. 1557 - 1565 (2007/10/03)
The γ-radiolysis of 1-arylcyclopentenes [Ar = Ph (1a); 4-ClC6 H4 (1b); 4-MeC6H4 (1c); 4-MeOC6H4 (1d)] at 77 K initially gave transient absorption bands attributable to their monomer cation radicals (1a(·)+ - 1d(·)+), with λ(max) around 400 and 650 - 730 nm. In the case of 1a, 1b, and 1c, simultaneous formation of new absorption bands with λ(max) around 480 - 500 nm, attributable to the dimer cation radicals, was clearly observed upon warming along with a decrease in the monomer cation radical absorption bands. Using 355-nm laser photolysis at room temperature and an N- methylquinolinium salt as an electron acceptor, the rate constants for the formation of the dimer cation radicals (k(dimer)) and the reaction-rate constants for 1(·)+ with methanol (k(MeOH)) were determined. The reactivities of 1(·)+ with 1 and with methanol are discussed on the basis of the results obtained by a semiempirical molecular orbital calculation using the PM3 method. The results indicate that the reactivities of 1(·)+ depend not on its structure but on the charge density of the ethylene bond. In addition, dimerization of the cycloalkene cation radicals with larger ring size than 1, such as 1-phenylcyclohexene, 1-phenylcycloheptene, and 1- phenylcyclooctene cation radicals, was found to be remarkably dependent on the ring size.
1,n-Radical ions. Photosensitized (electron transfer) carbon-carbon bond cleavage. Formation of 1,6-radical cations
Arnold, Donald R.,Lamont, Laurie J.,Perrott, Allyson L.
, p. 225 - 233 (2007/10/02)
The reactivity of the radical cations of methyl 2,2-diphenylcyclohexyl ether (7), 6,6-diphenyl-1,4-dioxaspirodecane (8), methyl cis- and trans-2-phenylcyclohexyl ether (9cis and trans), and 6-phenyl-1,4-dioxaspirodecane (10), generated by photos
Photosensitized (electron transfer) carbon-carbon bond cleavage of radical cations: the 2-phenylethyl ether and acetal systems
Arnold, Donald R.,Lamont, Laurie J.
, p. 2119 - 2127 (2007/10/02)
The scope of the photosensitized (electron transfer) carbon-carbon bond cleavage involving radical cations has been defined for 2-phenylethyl ethers and acetals.The thresholds for reactivity of the monophenylethyl and gem-diphenylethyl derivatives are compared.While the radical cation of methyl 2,2-diphenylethyl ether (7) cleaves to give ultimately diphenylmethane (2) and dimethoxymethane (8), the radical cation of methyl 2-phenylethyl ether (9) was stable under these conditions.In contrast to the lack of reactivity of the radical cation of 9, the radical cations of methyl 2-phenyl-2-propyl ether (11), methyl 2-phenylcyclopentyl ether (13), and 2-phenylmethyl-1,3-dioxolane (16) cleave.Cleavage in the monophenylethyl series is limited to formation of a carbocation at least as stable as the secondary α-oxyalkyl or di-α-oxyalkyl.The basis for predicting this type of reactivity of radical cations is defined.The rate of carbon-carbon bond cleavage is increased the oxidation potential of the molecule, by decreasing the carbon-carbon bond strength, and (or) by decreasing the oxidation potential of that fragment that will become the carbocation.The results obtained from the reactions of 2-diphenylmethyl-1,3-dioxolane (14) and 2-phenylmethyl-1,3-dioxolane (16) cast doubt on the published oxidation potential for the 1,3-dioxolan-2-yl radical.Key words: photochemistry, radical cation, electron transfer, bond cleavage, radical.
