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dc.contributor.authorChantler, Thomas*
dc.contributor.authorPerrin, Victoria L.*
dc.contributor.authorDonkor, Rachel E.*
dc.contributor.authorCawthorne, Richard S.*
dc.contributor.authorBowen, Richard D.*
dc.date.accessioned2009-02-09T10:06:58Z
dc.date.available2009-02-09T10:06:58Z
dc.date.issued2004en
dc.identifier.citationChantler T, Perrin VL, Donkor RE, Cawthorne RS and Bowen RD (2004) Proximity Effects in the Electron Impact Mass Spectra of 2-Substituted Benzazoles. International Journal of Mass Spectrometry. 236 (1-3): 65-80. Special issue: In honour of Dudley H. Williams.en
dc.identifier.urihttp://hdl.handle.net/10454/2351
dc.descriptionNoen
dc.description.abstractThe 70 eV electron impact mass spectra of a wide range of 2-substituted benzazoles are reported and discussed. Particular attention is paid to the mechanistic significance and analytical utility of [M–H]+ and [M–X]+ signals in the spectra of benzazoles in which the 2-substituent contains a terminal aryl group with one or more substituents, X. Loss of H or X occurs preferentially from an ortho-position from ionized 2-benzylbenzimidazoles, 2-phenethylbenzimidazoles, 2-styrylbenzimidazoles, 2-styrylbenzoxazoles and 2-styrylbenzothiazoles. In the three styrylbenzazole series, the [M–H]+ and/or [M–X]+ signals dominate the spectra. This unusually facile loss of H or X may be attributed to a proximity effect, in which cyclization of the ionized molecule is followed by elimination of an ortho-substituent to give an exceptionally stable polycyclic ion. Formation of a new five- or six-membered ring by the proximity effect occurs rapidly; cyclization to a seven-membered ring takes place rather less readily; but formation of a ring with only four atoms or more than seven atoms is not observed to a significant extent. The proximity effect competes effectively with loss of a methyl radical by simple cleavage of an ethyl, isopropyl and even a t-butyl group in the pendant aromatic ring of ionized 2-(4-alkylstyryl) benzazoles.en
dc.language.isoenen
dc.relation.isreferencedbyhttps://doi.org/10.1016/j.ijms.2004.05.012en
dc.subjectBenzimidazolesen
dc.subjectBenzoxazolesen
dc.subjectBenzothiazolesen
dc.subjectProximity effecten
dc.subjectRearrangementen
dc.subjectHydrogen atom eliminationen
dc.subjectDoubly-chargeden
dc.titleProximity Effects in the Electron Impact Mass Spectra of 2-Substituted Benzazolesen
dc.status.refereedYesen
dc.typeArticleen


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