86013-00-5Relevant articles and documents
Reversible Tautomerization of Radical Cations. Photoionization of 2-Methoxyethanol and 3-Methoxy-1-propanol
Biermann, H. W.,Morton, Thomas Hellman
, p. 5025 - 5030 (1983)
Evidence for intramolecular hydrogen exchange between OH and OCH3 groups is observed in PIMS studies of deuterated analogues of title compounds.Isopotic labeling demonstrates the unimolecular tautomerization of the molecular ion a, CH3OCH2(CH2)mCH2OH+., to structure b, .CH2OCH2(CH2)mCH2OH2+.In the case m = 0, Lyman α photons (122 nm) from a hydrogen resonance lamp have an energy that corresponds to the first vertical IP.Irradiation of DOCH2CH2OCH3 at this wavelength yields CH3OCH2+ and CH2DOCH2+ in a 2:1 ratio.Each of these compounds also yields both +. and +..The d3 analogue also yields +.., which must result from reversible a b interconversion.The d4 analogue DOCH2CH2OCD3 yields CD3OCH2+, +., and +., but neglectible quantities of CD2OHCH2+ or +..Isotopic scrambling must therefore be limited to the interchange of methoxy and hydroxy hydrogens.Examination of HOCD2CH2OCH3 provides confirmation, since no scrambling is observed.The a b interconversion is faster than bond cleavages, but the relative rate of cleavage increases with photon energy.Through-space inreraction is discounted as a major effect on reactivity, because the tautomerization also occurs for HOCH2CH2CH2OCD3.A stepwize mechanism, a .OCH2(CH2)mCH2O(CH39H+ HOCH2(CH2)mCH2O(CH2.)H+ b, is put forth to unify observed decomposition pathways.
Searching for the Ionized Alkene/Alkanol Complexes +./HOCH3> and +./HOCH2CH3>
Cao, J. R.,George, M.,Holmes, John L.
, p. 481 - 485 (2007/10/02)
Experiments on a variety of isomeric +. and +. ions have failed to produce direct evidence for the involvement of the complex ions +./HOCH3> and +./HOC2H5>.For the isomers studied, the rearrangements prior to their dissociation of lowest energy requirement (loss of H2O and C2H5., respectively) are proposed to involve distonic and ylid ions.
