39493-21-5Relevant articles and documents
A combined neutralization-reionization mass spectrometric and theoretical study of oxyallyl and other elusive [C3,H4,O] neutrals
Schalley, Christoph A.,Blanksby, Stephen,Harvey, Jeremy N.,Schroeder, Detlef,Zummack, Waltraud,Bowie, John H.,Schwarz, Helmut
, p. 987 - 1009 (1998)
Five different anionic [C3′H4′O]?- isomers, i.e. the radical anions of acrolein, acetyl carbene, formyl methyl carbene, methoxy vinylidene, and oxyallyl are generated in an ion beam mass spectrometer and subjected to neutralization-reionization (NR) mass spectrometric experiments including neutral and ion decomposition difference (NIDD) mass spectrometry; the latter allows for the examination of the neutrals' unimolecular reactivity. Further, the anionic, the singlet and triplet neutral, and the cationic [C3′H4′O] ?-/0/?+ potentialenergy surfaces are calculated at the B3LYP/6-311++G(d,p) level of theory. For some species, notably the singlet state of oxyallyl, the theoretical treatment is complemented by G2, CASSCF, and MR-CI calculations. Theory and experiment are in good agreement in that at the neutral stage (i) acrolein does not react within the μsec timescale, (ii) acetyl and formyl methyl carbenes isomerize to methyl ketene, (iii) methoxy vinylidene rearranges to methoxy acetylene, (iv) singlet 1A1 oxyallyl undergoes ring closure to cyclopropanone, and (v) triplet 3B2 oxyallyl may have a lifetime sufficient to survive a NR experiment.
Chemical Ionization Mass Spectra of Selected C3H6O Compounds
Bowen, Richard D.,Harrison, Alex G.
, p. 159 - 166 (1981)
The chemical ionization mass spectra of five isomers of C3H6O (acetone, propionaldehyde, oxetane, propylene oxide and allyl alcohol) have been determined using a variety of reagent gases (H2, D2, N2/H2, CO2/H2 and CO/H2).The + ions produced by protonation of these isomers undergo very similar reactions to those reported for analogous + metastable ions; however, decomposing ions generated by chemical ionization appear to have somewhat higher internal energies.The results of 2H labelling studies (D2 reagent gas or labelled analogues of C3H6O) indicate that protonation occurs mainly on oxygen and are consistent with previous investigations of metastable oxonium ions.The protonated acetone ion is particularly stable, in agreement with the higher activation energies for fragmentation of this isomer than for other + structures.As the calculated heat of protonation of C3H6O is reduced by changing the reagent gas, so the extent to which fragmentation occurs decreases.This is discussed in the context of competition between fragmentation and collisional stabilization of the excited +* ion.It is concluded that on average a large fraction (approching 1) of the exothermicity of the protonation reaction resides in the +* ions produced initially.
The influence of H/D kinetic isotope effect on radiation-induced transformations of hydroxyl-containing compounds in aqueous solutions
Bekish, Andrei V.,Nepachalovich, Palina S.,Shadyro, Oleg I.,Shmanai, Vadim V.
, p. 732 - 744 (2020/12/28)
Vicinal diols and its derivatives can be exploited as model compounds for the investigation of radiation-induced free-radical transformations of hydroxyl-containing biomolecules such as carbohydrates, phospholipids, ribonucleotides, amino acids, and peptides. In this paper, for the first time, the prospects of isotope reinforcement approach in inhibiting free-radical transformations of hydroxyl-containing compounds in aqueous solutions are investigated on the example of radiolysis of 1,2-propanediol and 1,2-propanediol-2-d1 aqueous solutions. At an absorbed dose rate of 0.110 ± 0.003 Gy·s?1 a profound kinetic isotope effect (KIE) is observed for the non-branched chain formation of acetone, which is a final dehydration product of predominant carbon-centred radicals CH3·C(OH)CH2OH. In 0.1 and 1 M deaerated solutions at pH 7.00 ± 0.01, the values of KIE are 8.9 ± 1.7 and 15.3 ± 3.1, respectively. A rationale for the fact that a strong KIE takes place only in the case of chain processes, which may occur during free-radical transformations of vicinal diols, is also provided herein based on the results of 2-propanol and 2-propanol-2-d1 indirect radiolysis. Lastly, the lack of KIE is shown in the case of 2-butanone formation from 2,3-butanediol or 2,3-butanediol-2,3-d2. This indicates that the type (primary, secondary) of the β-carbonyl radicals formed as a result of CH3·C(OH)CH(OH)R (R = H, CH3) dehydration determines the manifestation of the effect.
