Praseodymium(III) NMR shift reagent, which is an upfield shift reagent, is focused on for assessment of enantiomeric excess and resolution of methyl sulfonium ions. A series of alkylmethylphenylsulfonium ions were analyzed, where alkyl is ethyl (I), butyl(H), octyl (III), and benzyl(IY). The praseodymium agent gives base-lined resolution of the ortho hydrogens resonance for I and IH. All spectra are strongly temperature-dependent. I is shifted more than ED, consistent with a steric effect. Assignments for I were made by gradually increasing the concentration of the shift reagent and by analyzing R-enriched I. Racemization of R-enriched isomer of I by pyramidal inversion was observed at 50 °C.
","abstract_html":"<p>Praseodymium(III) NMR shift reagent, which is an upfield shift reagent, is focused on for assessment of enantiomeric excess and resolution of methyl sulfonium ions. A series of alkylmethylphenylsulfonium ions were analyzed, where alkyl is ethyl (I), butyl(H), octyl (III), and benzyl(IY). The praseodymium agent gives base-lined resolution of the ortho hydrogens resonance for I and IH. All spectra are strongly temperature-dependent. I is shifted more than ED, consistent with a steric effect. Assignments for I were made by gradually increasing the concentration of the shift reagent and by analyzing R-enriched I. Racemization of R-enriched isomer of I by pyramidal inversion was observed at 50 °C.</p>","abstract_has_math":false,"creators":["Son, Ea-Ji-Ru"],"institution":null,"degree_name":"Master of Science","degree_level":null,"degree_discipline":"Department of Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1997,"date_issued":"1997-12-01T08:00:00Z","date_published":"1997-12-01T08:00:00Z","updated_at":"2026-07-24T06:07:22Z","subjects":["Chemistry"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.wku.edu/theses/358","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Son, Ea-Ji-Ru"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Department of Chemistry"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.wku.edu/theses/358"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Praseodymium(III) NMR shift reagent, which is an upfield shift reagent, is focused on for assessment of enantiomeric excess and resolution of methyl sulfonium ions. A series of alkylmethylphenylsulfonium ions were analyzed, where alkyl is ethyl (I), butyl(H), octyl (III), and benzyl(IY). The praseodymium agent gives base-lined resolution of the ortho hydrogens resonance for I and IH. All spectra are strongly temperature-dependent. I is shifted more than ED, consistent with a steric effect. Assignments for I were made by gradually increasing the concentration of the shift reagent and by analyzing R-enriched I. Racemization of R-enriched isomer of I by pyramidal inversion was observed at 50 °C.
"]},{"key":"dc:title","label":"Title","values":["Studies on Resolution of Enantiomeric Dialkylaryl Sulfonium Ions with NMR Shift Reagents"]}]}],"canonical_facts":{"dc:creator":["Son, Ea-Ji-Ru"],"dc:description.abstract":["Praseodymium(III) NMR shift reagent, which is an upfield shift reagent, is focused on for assessment of enantiomeric excess and resolution of methyl sulfonium ions. A series of alkylmethylphenylsulfonium ions were analyzed, where alkyl is ethyl (I), butyl(H), octyl (III), and benzyl(IY). The praseodymium agent gives base-lined resolution of the ortho hydrogens resonance for I and IH. All spectra are strongly temperature-dependent. I is shifted more than ED, consistent with a steric effect. Assignments for I were made by gradually increasing the concentration of the shift reagent and by analyzing R-enriched I. Racemization of R-enriched isomer of I by pyramidal inversion was observed at 50 °C.
"],"dc:identifier":["https://digitalcommons.wku.edu/theses/358"],"dc:subject":["Chemistry"],"dc:title":["Studies on Resolution of Enantiomeric Dialkylaryl Sulfonium Ions with NMR Shift Reagents"],"dc:type":["Thesis"],"thesis:degree_discipline":["Department of Chemistry"],"thesis:degree_name":["Master of Science"]},"updated_at":"2026-07-24T06:07:22Z"}