Please use this identifier to cite or link to this item: https://olympias.lib.uoi.gr/jspui/handle/123456789/7927
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dc.contributor.authorGerothanassis, I. P.en
dc.contributor.authorVakka, C.en
dc.contributor.authorTroganis, A.en
dc.date.accessioned2015-11-24T16:35:18Z-
dc.date.available2015-11-24T16:35:18Z-
dc.identifier.issn1064-1866-
dc.identifier.urihttps://olympias.lib.uoi.gr/jspui/handle/123456789/7927-
dc.rightsDefault Licence-
dc.subjectnuclear magnetic-resonanceen
dc.subjectacetyl-l-prolineen
dc.subjectchemical-shiftsen
dc.subjectaqueous-solutionen
dc.subjectspectroscopyen
dc.subjectwateren
dc.subjectturnsen
dc.subjectbonden
dc.subjectcisen
dc.subjectconformationen
dc.titleO-17 NMR studies of the solvation state of cis/trans isomers of amides and model protected peptidesen
heal.typejournalArticle-
heal.type.enJournal articleen
heal.type.elΆρθρο Περιοδικούel
heal.identifier.secondary<Go to ISI>://A1996UQ67800002-
heal.languageen-
heal.accesscampus-
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιώνel
heal.publicationDate1996-
heal.abstractO-17 shielding constants have been utilized to investigate solvation differences of the cis/trans isomers of N-methylformamide (NMF), N-ethylformamide (NEF), and tert-butylformamide (TBF) in a variety of solvents with particular emphasis on aqueous solution. Comparisons are also made with protected peptides of the formulas CH3CO-YOH, CH3CO-Y-NHR (Y = Pro, Sar), and CH3CO-Y-Z-NHR (Y = Pro; Z = D-Ala) selectively enriched in O-17 at the acetyl oxygen atom. Hydration at the amide oxygen induces large and specific modifications of the O-17 shielding constants, which are practically the same for the cis and trans isomers of NMF, NEF, and the protected peptides. For tert-butylformamide, the strong deshielding of the trans isomer compared to that of the cis isomer may be attributed to an out-of-plane (torsion-angle) deformation of the amide bond and/or a significant reduction of solvation of the trans isomer due to steric inhibition of the bulky tert-butyl group. Good linear correlation between delta(O-17) of amides and delta(O-17) of acetone was found for different solvents which have varying dielectric constants and solvation abilities. Sum-over-states calculations, within the solvaton model, underestimate effects of the dielectric constant of the medium on O-17 shielding, while finite-perturbation-theory calculations give good agreement with the experiment. (C) 1996 Academic Press, Inc.en
heal.journalNameJournal of Magnetic Resonance Series Ben
heal.journalTypepeer reviewed-
heal.fullTextAvailabilityTRUE-
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