{"id":{"repo_id":"maryland","oai_identifier":"oai:drum.lib.umd.edu:1903/19482"},"canonical_url":"https://search.dev.ndltd.org/etd/maryland/oai:drum.lib.umd.edu:1903/19482","repository":{"repo_id":"maryland","name":"University of Maryland","base_url":"https://api.drum.lib.umd.edu/server/oai/request"},"display":{"title":"INTRAMOLECULAR CARBON-NITROGEN COUPLING FROM ISOLATED MONOHYDROCARBYL PALLADIUM(IV) COMPLEXES PREPARED USING H2O2 AS TERMINAL OXIDANT","abstract":"Carbon-nitrogen coupling is achieved traditionally by coupling of aryl halides and amines through a Pd(0)/Pd(II) catalytic cycle (Buchwald-Hartwig amination). A newer, more atom-economical approach to the synthesis of amines is based on oxidative C-H amination. Recent studies of C-H amination propose the involvement of Pd(II)/Pd(IV) catalytic cycle through a C-H activation step. This work seeks to develop new stoichiometric and catalytic ways of forming C-N bonds through a Pd(II)/Pd(IV) cycle using H2O2 as terminal oxidant. In this effort, di-2-pyridylketone(dpk) ligated palladacycles were synthesized, oxidized with H2O2, and the reductive elimination of the high oxidation state Pd(IV, d6) containing species monitored. N-R-2-aminobiphenyl – derived substrates with electron donating groups (R = H, Me, Et) readily form carbazoles at room temperature without formation of appreciable amounts of intermediates. The use of electron withdrawing group (R = COCH3, COCF3, SO2CH3, SO2CF3) slows down the reaction for intermediates to be observed and isolated. Mechanistic studies of the first ever C(sp2)-N reductive elimination from an isolated Pd(IV, d6) intermediate was observed to be accelerated in the presence of acids. Reductive elimination is proposed to occur from a 6-coordinate Pd(IV, d6) center. The dpk ligated Pd(IV, d6) palladacycles derived from 4-X-substituted N-SO2CF3-2-tert-butylaniline (X = H, Br, I), reductively eliminate the corresponding C(sp3)-N coupled products, 5-X-substituted indolines in high yield only in the presence of halohalic acids (HCl, HBr and HI). This confirms the importance of a proton source and a nucleophilic anion for this process to take place. Reductive elimination is proposed to occur through several competing pathways based on the fractional order of reaction with respect to [Br-] in solution. Catalytic heterocyclization reaction was achieved using H2O2 with N-acetyl-2-aminobiphenyl to form N-acetylcarbazole with yields dependent on temperature and rate of addition of H2O2.","abstract_html":"Carbon-nitrogen coupling is achieved traditionally by coupling of aryl halides and amines through a Pd(0)/Pd(II) catalytic cycle (Buchwald-Hartwig amination). A newer, more atom-economical approach to the synthesis of amines is based on oxidative C-H amination. Recent studies of C-H amination propose the involvement of Pd(II)/Pd(IV) catalytic cycle through a C-H activation step. This work seeks to develop new stoichiometric and catalytic ways of forming C-N bonds through a Pd(II)/Pd(IV) cycle using H2O2 as terminal oxidant. In this effort, di-2-pyridylketone(dpk) ligated palladacycles were synthesized, oxidized with H2O2, and the reductive elimination of the high oxidation state Pd(IV, d6) containing species monitored. N-R-2-aminobiphenyl – derived substrates with electron donating groups (R = H, Me, Et) readily form carbazoles at room temperature without formation of appreciable amounts of intermediates. The use of electron withdrawing group (R = COCH3, COCF3, SO2CH3, SO2CF3) slows down the reaction for intermediates to be observed and isolated. Mechanistic studies of the first ever C(sp2)-N reductive elimination from an isolated Pd(IV, d6) intermediate was observed to be accelerated in the presence of acids. Reductive elimination is proposed to occur from a 6-coordinate Pd(IV, d6) center. The dpk ligated Pd(IV, d6) palladacycles derived from 4-X-substituted N-SO2CF3-2-tert-butylaniline (X = H, Br, I), reductively eliminate the corresponding C(sp3)-N coupled products, 5-X-substituted indolines in high yield only in the presence of halohalic acids (HCl, HBr and HI). This confirms the importance of a proton source and a nucleophilic anion for this process to take place. Reductive elimination is proposed to occur through several competing pathways based on the fractional order of reaction with respect to [Br-] in solution. Catalytic heterocyclization reaction was achieved using H2O2 with N-acetyl-2-aminobiphenyl to form N-acetylcarbazole with yields dependent on temperature and rate of addition of H2O2.","abstract_has_math":false,"creators":["Abada, Elikplim"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Chemistry","school":null,"contributors":[],"advisors":["Vedernikov, Andrei N"],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017","date_published":"2017","updated_at":"2026-07-24T03:02:12Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.13016/M2827G"],"render_values":[{"text":"https://doi.org/10.13016/M2827G","href":"https://doi.org/10.13016/M2827G","code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/1903/19482","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Vedernikov, Andrei N"]},{"key":"dc:contributor.department","label":"Department","values":["Chemistry"]},{"key":"dc:creator","label":"Author","values":["Abada, Elikplim"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2017-06-22T06:23:21Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2017-06-22T06:23:21Z"]},{"key":"dc:date.issued","label":"Date","values":["2017"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.13016/M2827G"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1903/19482"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Carbon-nitrogen coupling is achieved traditionally by coupling of aryl halides and amines through a Pd(0)/Pd(II) catalytic cycle (Buchwald-Hartwig amination). A newer, more atom-economical approach to the synthesis of amines is based on oxidative C-H amination. Recent studies of C-H amination propose the involvement of Pd(II)/Pd(IV) catalytic cycle through a C-H activation step. This work seeks to develop new stoichiometric and catalytic ways of forming C-N bonds through a Pd(II)/Pd(IV) cycle using H2O2 as terminal oxidant. In this effort, di-2-pyridylketone(dpk) ligated palladacycles were synthesized, oxidized with H2O2, and the reductive elimination of the high oxidation state Pd(IV, d6) containing species monitored. N-R-2-aminobiphenyl – derived substrates with electron donating groups (R = H, Me, Et) readily form carbazoles at room temperature without formation of appreciable amounts of intermediates. The use of electron withdrawing group (R = COCH3, COCF3, SO2CH3, SO2CF3) slows down the reaction for intermediates to be observed and isolated. Mechanistic studies of the first ever C(sp2)-N reductive elimination from an isolated Pd(IV, d6) intermediate was observed to be accelerated in the presence of acids. Reductive elimination is proposed to occur from a 6-coordinate Pd(IV, d6) center. The dpk ligated Pd(IV, d6) palladacycles derived from 4-X-substituted N-SO2CF3-2-tert-butylaniline (X = H, Br, I), reductively eliminate the corresponding C(sp3)-N coupled products, 5-X-substituted indolines in high yield only in the presence of halohalic acids (HCl, HBr and HI). This confirms the importance of a proton source and a nucleophilic anion for this process to take place. Reductive elimination is proposed to occur through several competing pathways based on the fractional order of reaction with respect to [Br-] in solution. Catalytic heterocyclization reaction was achieved using H2O2 with N-acetyl-2-aminobiphenyl to form N-acetylcarbazole with yields dependent on temperature and rate of addition of H2O2."]},{"key":"dc:title","label":"Title","values":["INTRAMOLECULAR CARBON-NITROGEN COUPLING FROM ISOLATED MONOHYDROCARBYL PALLADIUM(IV) COMPLEXES PREPARED USING H2O2 AS TERMINAL OXIDANT"]}]}],"canonical_facts":{"dc:contributor.advisor":["Vedernikov, Andrei N"],"dc:contributor.department":["Chemistry"],"dc:creator":["Abada, Elikplim"],"dc:date.accessioned":["2017-06-22T06:23:21Z"],"dc:date.available":["2017-06-22T06:23:21Z"],"dc:date.issued":["2017"],"dc:description.abstract":["Carbon-nitrogen coupling is achieved traditionally by coupling of aryl halides and amines through a Pd(0)/Pd(II) catalytic cycle (Buchwald-Hartwig amination). A newer, more atom-economical approach to the synthesis of amines is based on oxidative C-H amination. Recent studies of C-H amination propose the involvement of Pd(II)/Pd(IV) catalytic cycle through a C-H activation step. This work seeks to develop new stoichiometric and catalytic ways of forming C-N bonds through a Pd(II)/Pd(IV) cycle using H2O2 as terminal oxidant. In this effort, di-2-pyridylketone(dpk) ligated palladacycles were synthesized, oxidized with H2O2, and the reductive elimination of the high oxidation state Pd(IV, d6) containing species monitored. N-R-2-aminobiphenyl – derived substrates with electron donating groups (R = H, Me, Et) readily form carbazoles at room temperature without formation of appreciable amounts of intermediates. The use of electron withdrawing group (R = COCH3, COCF3, SO2CH3, SO2CF3) slows down the reaction for intermediates to be observed and isolated. Mechanistic studies of the first ever C(sp2)-N reductive elimination from an isolated Pd(IV, d6) intermediate was observed to be accelerated in the presence of acids. Reductive elimination is proposed to occur from a 6-coordinate Pd(IV, d6) center. The dpk ligated Pd(IV, d6) palladacycles derived from 4-X-substituted N-SO2CF3-2-tert-butylaniline (X = H, Br, I), reductively eliminate the corresponding C(sp3)-N coupled products, 5-X-substituted indolines in high yield only in the presence of halohalic acids (HCl, HBr and HI). This confirms the importance of a proton source and a nucleophilic anion for this process to take place. Reductive elimination is proposed to occur through several competing pathways based on the fractional order of reaction with respect to [Br-] in solution. Catalytic heterocyclization reaction was achieved using H2O2 with N-acetyl-2-aminobiphenyl to form N-acetylcarbazole with yields dependent on temperature and rate of addition of H2O2."],"dc:identifier":["https://doi.org/10.13016/M2827G"],"dc:identifier.uri":["http://hdl.handle.net/1903/19482"],"dc:language.iso":["en"],"dc:title":["INTRAMOLECULAR CARBON-NITROGEN COUPLING FROM ISOLATED MONOHYDROCARBYL PALLADIUM(IV) COMPLEXES PREPARED USING H2O2 AS TERMINAL OXIDANT"],"dc:type":["Dissertation"]},"updated_at":"2026-07-24T03:02:12Z"}