1,983 research outputs found
Unidirectional triple and double hydrogen rearrangement reactions in the radical cations of gamma-arylalkanols
No full textKuck D, Filges U. Unidirectional triple and double hydrogen rearrangement reactions in the radical cations of gamma-arylalkanols. Organic Mass Spectrometry. 1988;23(9):643-653.A novel fragmentation reaction accompanied by the unidirectional migration of three hydrogen atoms has been found in the radical cations of -arylpropanols with electron-donating substituents in the para position. This triple hydrogen (3H) rearrangement reaction is the dominant fragmentation channel of the long-lived molecular ions of trans-2-(4-dimethylaminobenzyl)-l-indanol, 2, but it occurs also in simpler -arylpropanol ions. Deuterium labelling of 2 reveals that the three hydrogen atoms originate with extraordinarily high specificity from the C(l), C(2) and O positions of the alcohol moiety. Cis- and 3-substituted isomers do not undergo this reaction. Along with the 3H rearrangement reaction a unidirectional double hydrogen (2H) rearrangement reaction takes place independently and with less specificity in the trans-2-(4-X-benzyl)-l-indanol ions 1+· and 2+·. No hydrogen exchange occurs during the 3H and 2H rearrangement reactions. Mechanistic alternatives of these unusual fragmentation reactions are discussed; the experimental evidence strongly favours pathways via several intermediate ion-neutral complexes
Internal reactions of ion/molecule complexes from isomeric protonated formyl-and acetyl-naphthalenes
No full textFilges U, Grützmacher H-F. Internal reactions of ion/molecule complexes from isomeric protonated formyl-and acetyl-naphthalenes. International Journal of Mass Spectrometry and Ion Processes. 1988;83(1-2):111-133
Fragmentations of protonated acetophenones via intermediate ion-molecule complexes
No full textFilges U, Grützmacher H-F. Fragmentations of protonated acetophenones via intermediate ion-molecule complexes. Organic Mass Spectrometry. 1987;22(7):444-450
Remote fragmentations of protonated aromatic carbonyl compounds via internal reactions in intermediary ion-neutral complexes
No full textThielking G, Filges U, Grützmacher H-F. Remote fragmentations of protonated aromatic carbonyl compounds via internal reactions in intermediary ion-neutral complexes. Journal of the American Society for Mass Spectrometry. 1992;3(4):417-426.Protonated aromatic aldehydes and methyl ketones 1a-10a, carrying initially the proton at the carbonyl group, are prepared by electron impact-induced loss of a methyl radical from 1-arylethanols and 2-aryl-2-propanols, respectively. The aryl moiety of the ions corresponds to a benzene group, a naphthalene group, a phenanthrene group, a biphenyl group, and a terphenyl group, respectively, each substituted by a CH3OCH2 side-chain as remote from the acyl substituent as possible. The characteristic reactions of the metastable ions, studied by mass-analyzed ion kinetic energy spectrometry, are the elimination of methanol, the formation of CH3OCH2+ ions, and the elimination of an ester RCOOCH3 (R = H and CH3). The mechanisms of these fragmentations were studied by using D-labeled derivatives. Confirming earlier results, it is shown that the ester elimination, at least from the protonated aryl methyl ketones, has to proceed by an intermediate [acyl cation/arylmethyl methyl ether]-complex. The relative abundances of the elimination of methanol and of the ester decrease and increase, respectively, with the size of the aromatic system. Clearly, the fragmentation via intermediate ion-neutral complexes is favored for the larger ions. Furthermore, the acyl cation of these complexes can move unrestricted over quite large molecular distances to react with the remote CH3OCH2-side-chain, contrasting the restricted migration of a proton by 1,2-shifts ("ring walk") in these systems
Ion-Molekül-Komplexe: reaktive Zwischenstufen bei massenspektrometrischen Fragmentierungen von substituierten 1-Arylalkanolen
No full textFilges U. Ion-Molekül-Komplexe: reaktive Zwischenstufen bei massenspektrometrischen Fragmentierungen von substituierten 1-Arylalkanolen. Bielefeld; 1986
Proton migration in naphthalenium ions via [sigma] and [pi] complexes
No full textFilges U, Grützmacher H-F. Proton migration in naphthalenium ions via [sigma] and [pi] complexes. International Journal of Mass Spectrometry and Ion Processes. 1988;83(1-2):93-109
Fragmentations of protonated benzaldehydes via intermediate ion/molecule complexes
No full textFilges U, Grützmacher H-F. Fragmentations of protonated benzaldehydes via intermediate ion/molecule complexes. Organic Mass Spectrometry. 1986;21(10):673-680
Tractatio Iuris Publici De Serenissimis Potentissimisque Ducibus Brunsvicensibus Et Luneburgensibus / D.O.M.A. Praeside ... Dn. Joh. Ulrico Pregizero ... In Illustri Collegio Ad Diem 10. Decembr. Placido Eruditorum Examini sistit Author Christian Ulrich Blum
No full textTRACTATIO IURIS PUBLICI DE SERENISSIMIS POTENTISSIMISQUE DUCIBUS BRUNSVICENSIBUS ET LUNEBURGENSIBUS / D.O.M.A. PRAESIDE ... DN. JOH. ULRICO PREGIZERO ... IN ILLUSTRI COLLEGIO AD DIEM 10. DECEMBR. PLACIDO ERUDITORUM EXAMINI SISTIT AUTHOR CHRISTIAN ULRICH BLUM
Tractatio Iuris Publici De Serenissimis Potentissimisque Ducibus Brunsvicensibus Et Luneburgensibus / D.O.M.A. Praeside ... Dn. Joh. Ulrico Pregizero ... In Illustri Collegio Ad Diem 10. Decembr. Placido Eruditorum Examini sistit Author Christian Ulrich Blum (1)
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Supplementary movies of the dynamic rupture and tsunami models published in Ulrich et al. (2019)
No full text<p>Supplementary movies of the dynamic rupture and tsunami models published in Ulrich et al. (2019)</p>
<p>movie_Sulawesi_SR-cp.mov: Absolute slip rate (m/s) across the fault network during the earthquake. Author: Thomas Ulrich</p>
<p>movie_Sulawesi_wavefield-cp.mov: Absolute slip rate (m/s) and wavefield (absolute particle velocity in m/s) across the fault network during the earthquake. Author: Thomas Ulrich</p>
<p>SulawesiTanioka.mp4: Sea surface height (m) predicted by the tsunami scenario. Author: Stefan Vater</p>
<p>reference: Ulrich, T., Vater, S., Madden, E. H., Behrens, J., van Dinther, Y., van Zelst, I., Fielding, E. J., Liang, C. & Gabriel, A. A. (2019). Coupled, Physics-based Modeling Reveals Earthquake Displacements are Critical to the 2018 Palu, Sulawesi Tsunami. doi: 10.31223/osf.io/3bwqa.</p>
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