2154-62-3Relevant articles and documents
Hydroxymethylcyclopropane on oxygen-covered Mo(110): A radical clock on a surface
Kretzschmar,Levinson,Friend
, p. 12395 - 12396 (2000)
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Krusic et al.
, p. 250 (1977)
Ibuki et al.
, p. 8,9, 11 (1976)
Alkanethioimidoyl Radicals: Evaluation of β-Scission Rates and of Cyclization onto S-Alkenyl Substituents
Minozzi, Matteo,Nanni, Daniele,Walton, John C.
, p. 2056 - 2069 (2007/10/03)
Thioimidoyl radicals were generated by addition of alkylsulfanyl radicals to alkyl isonitriles and were characterized by electron paramagnetic resonance (EPR) spectroscopy. The β-scissions of their C·S-C bonds were studied by variable-temperature EPR spectroscopy and the fragmentation rate constants and activation energies were calculated. The scission rates depend on the stability of the released alkyl radicals but in any case, at room temperature, the processes were fast. Data collected on similar oxyimidoyls showed that their fragmentations are slightly slower compared to those of analogous thioimidoyls. The scission rates of selenoimidoyls could not be studied by EPR and were evaluated by theoretical calculations. EPR experiments also enabled both β-scission and 5-exo ring closure rate constants of two S-but-3-enyl-substituted imidoyl radicals to be determined, showing that cyclization prevails only at low temperatures. Density functional theory (DFT) theoretical calculations predicted that the fragmentation process preferentially occurs from the s-cis rotamers (X-C bond) of the imidoyl radicals. Thio- and seleno-imidoyls (but not oxyimidoyls) prefer s-trans conformations so that their fragmentations involve prior rotation about the X-C bond.
Small rings, 91: Fragmentation of cyclobutane in a bromine-doped and undoped xenon matrix
Maier, Guenther,Senger, Stefan
, p. 45 - 47 (2007/10/03)
Irradiation (λ = 254 nm) of cyclobutane in a bromine-doped xenon matrix leads to ring opening in spite of the fact that cyclobutane does not absorb in this region. The main products are ethene and 1-butene. The same reaction, but less effectively, occurs upon irradiation with a laser (KrF laser, λ = 248 nm) in the absence of the halogen. The difference in the mechanisms of the two fragmentations is discussed. VCH Verlagsgesellschaft mbH, 1996.