{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/89732"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/89732","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Rapid Synthesis, Characterization, and Catalytic Function of Rhodium(III) and Iridium(III) Chloro-bridged Dimers","abstract":"Rh(III) and Ir(III) dimeric complexes with tunable cyclopentadienyl (Cp) rings have proven versatile for both catalysis and as synthetic precursors. An efficient microwave method to synthesize Rh(III) and Ir(III) dimeric complexes [(η5-ring)MCl]2(μ2-Cl)2, (where (η5-ring)MCl = (η5-Me4C5R)Rh(III)Cl or (η5-Me4C5R)Ir(III)Cl) was developed. A modular design for the substituted cyclopentadienes HC5Me4R was based on Grignard reactions of 2,3,4,5-tetramethylcyclopent-2-en-1-one (R = alkyl, 12 examples; R = aryl, 3 examples) or by SNAr reactions of potassium tetramethylcyclopentadienide with perfluoroarenes (R = perfluoroaryl, 3 examples). Reaction of the Me4CpHR ligands with [M(COD)](μ2-Cl)2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) produced the dimeric complexes [Cp*RMCl]2(μ2-Cl)2 in moderate to excellent yield. The resulting dimers were characterized by nuclear magnetic resonance (NMR) spectroscopy, single-crystal X-ray diffraction (XRD), high-resolution mass spectrometry (HRMS), elemental analysis, and examined as catalysts for oxidative lactonization of 1,4- and 1,5-diols. Oxidative lactonization of 1,4-butanediol to afford γ-butyrolactone proceeded selectively and efficiently using [(η5-Me4C5R)IrCl]2(μ2-Cl)2 as the catalyst. Several R substituents were tested to assess electronic substituent effects. The most active complex contained an electron donating group, R = CHMe2 and successfully catalyzed the formation of diols to lactones across a range of 1,4- and 1,5-diols, generally in high yield. Computational analysis of the rate-determining b-hydrogen elimination reactions provided an atomistic account of observed trends in reaction yield and selectivity as a function of substrate structure, while accounting neatly for the observed selective formation of lactones (vs. succinaldehyde) in the transfer dehydrogenation of 1,4-butyrolactone.","abstract_html":"Rh(III) and Ir(III) dimeric complexes with tunable cyclopentadienyl (Cp) rings have proven versatile for both catalysis and as synthetic precursors. An efficient microwave method to synthesize Rh(III) and Ir(III) dimeric complexes [(η5-ring)MCl]2(μ2-Cl)2, (where (η5-ring)MCl = (η5-Me4C5R)Rh(III)Cl or (η5-Me4C5R)Ir(III)Cl) was developed. A modular design for the substituted cyclopentadienes HC5Me4R was based on Grignard reactions of 2,3,4,5-tetramethylcyclopent-2-en-1-one (R = alkyl, 12 examples; R = aryl, 3 examples) or by SNAr reactions of potassium tetramethylcyclopentadienide with perfluoroarenes (R = perfluoroaryl, 3 examples). Reaction of the Me4CpHR ligands with [M(COD)](μ2-Cl)2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) produced the dimeric complexes [Cp*RMCl]2(μ2-Cl)2 in moderate to excellent yield. The resulting dimers were characterized by nuclear magnetic resonance (NMR) spectroscopy, single-crystal X-ray diffraction (XRD), high-resolution mass spectrometry (HRMS), elemental analysis, and examined as catalysts for oxidative lactonization of 1,4- and 1,5-diols. Oxidative lactonization of 1,4-butanediol to afford γ-butyrolactone proceeded selectively and efficiently using [(η5-Me4C5R)IrCl]2(μ2-Cl)2 as the catalyst. Several R substituents were tested to assess electronic substituent effects. The most active complex contained an electron donating group, R = CHMe2 and successfully catalyzed the formation of diols to lactones across a range of 1,4- and 1,5-diols, generally in high yield. Computational analysis of the rate-determining b-hydrogen elimination reactions provided an atomistic account of observed trends in reaction yield and selectivity as a function of substrate structure, while accounting neatly for the observed selective formation of lactones (vs. succinaldehyde) in the transfer dehydrogenation of 1,4-butyrolactone.","abstract_has_math":false,"creators":["Brown, Loren"],"institution":"Virginia Tech","degree_name":"Doctor of Philosophy","degree_level":"doctoral","degree_discipline":"Chemistry","degree_department":"Chemistry","school":null,"contributors":[],"advisors":[],"committee_chairs":["Merola, Joseph S.","Deck, Paul A."],"committee_members":["Lin, Feng","Yee, Gordon T."],"year":2019,"date_issued":"2019-06-03","date_published":"2019-06-03","updated_at":"2026-07-22T22:18:52Z","subjects":["iridium","rhodium","lactone","oxidative lactonization","transfer dehydrogenation","microwave synthesis","ligand effects"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:21089"],"render_values":[{"text":"vt_gsexam:21089","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/89732","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Merola, Joseph S.","Deck, Paul A."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Lin, Feng","Yee, Gordon T."]},{"key":"dc:contributor.department","label":"Department","values":["Chemistry"]},{"key":"dc:creator","label":"Author","values":["Brown, Loren"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2019-06-04T08:00:16Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2019-06-04T08:00:16Z"]},{"key":"dc:date.issued","label":"Date","values":["2019-06-03"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["iridium","rhodium","lactone","oxidative lactonization","transfer dehydrogenation","microwave synthesis","ligand effects"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:21089"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/89732"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Rh(III) and Ir(III) dimeric complexes with tunable cyclopentadienyl (Cp) rings have proven versatile for both catalysis and as synthetic precursors. An efficient microwave method to synthesize Rh(III) and Ir(III) dimeric complexes [(η5-ring)MCl]2(μ2-Cl)2, (where (η5-ring)MCl = (η5-Me4C5R)Rh(III)Cl or (η5-Me4C5R)Ir(III)Cl) was developed. A modular design for the substituted cyclopentadienes HC5Me4R was based on Grignard reactions of 2,3,4,5-tetramethylcyclopent-2-en-1-one (R = alkyl, 12 examples; R = aryl, 3 examples) or by SNAr reactions of potassium tetramethylcyclopentadienide with perfluoroarenes (R = perfluoroaryl, 3 examples). Reaction of the Me4CpHR ligands with [M(COD)](μ2-Cl)2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) produced the dimeric complexes [Cp*RMCl]2(μ2-Cl)2 in moderate to excellent yield. The resulting dimers were characterized by nuclear magnetic resonance (NMR) spectroscopy, single-crystal X-ray diffraction (XRD), high-resolution mass spectrometry (HRMS), elemental analysis, and examined as catalysts for oxidative lactonization of 1,4- and 1,5-diols. Oxidative lactonization of 1,4-butanediol to afford γ-butyrolactone proceeded selectively and efficiently using [(η5-Me4C5R)IrCl]2(μ2-Cl)2 as the catalyst. Several R substituents were tested to assess electronic substituent effects. The most active complex contained an electron donating group, R = CHMe2 and successfully catalyzed the formation of diols to lactones across a range of 1,4- and 1,5-diols, generally in high yield. Computational analysis of the rate-determining b-hydrogen elimination reactions provided an atomistic account of observed trends in reaction yield and selectivity as a function of substrate structure, while accounting neatly for the observed selective formation of lactones (vs. succinaldehyde) in the transfer dehydrogenation of 1,4-butyrolactone."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["Rhodium(III) and iridium(III) complexes are useful synthetic precursors, catalysts, and biologically active compounds. This dissertation explores a rapid synthesis of these metal complexes and their subsequent catalytic applications with 1,4- and 1,5-diols. The oxidative lactonization of diols with rhodium and iridium complexes is an attractive one-pot synthesis, opening a variety of lactones to be produced. Structural studies involving novel fluorinated rhodium and iridium chloro-bridged dimers are discussed in detail."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Doctor of Philosophy"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Rapid Synthesis, Characterization, and Catalytic Function of Rhodium(III) and Iridium(III) Chloro-bridged Dimers"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Merola, Joseph S.","Deck, Paul A."],"dc:contributor.committeemember":["Lin, Feng","Yee, Gordon T."],"dc:contributor.department":["Chemistry"],"dc:creator":["Brown, Loren"],"dc:date.accessioned":["2019-06-04T08:00:16Z"],"dc:date.available":["2019-06-04T08:00:16Z"],"dc:date.issued":["2019-06-03"],"dc:description.abstract":["Rh(III) and Ir(III) dimeric complexes with tunable cyclopentadienyl (Cp) rings have proven versatile for both catalysis and as synthetic precursors. An efficient microwave method to synthesize Rh(III) and Ir(III) dimeric complexes [(η5-ring)MCl]2(μ2-Cl)2, (where (η5-ring)MCl = (η5-Me4C5R)Rh(III)Cl or (η5-Me4C5R)Ir(III)Cl) was developed. A modular design for the substituted cyclopentadienes HC5Me4R was based on Grignard reactions of 2,3,4,5-tetramethylcyclopent-2-en-1-one (R = alkyl, 12 examples; R = aryl, 3 examples) or by SNAr reactions of potassium tetramethylcyclopentadienide with perfluoroarenes (R = perfluoroaryl, 3 examples). Reaction of the Me4CpHR ligands with [M(COD)](μ2-Cl)2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) produced the dimeric complexes [Cp*RMCl]2(μ2-Cl)2 in moderate to excellent yield. The resulting dimers were characterized by nuclear magnetic resonance (NMR) spectroscopy, single-crystal X-ray diffraction (XRD), high-resolution mass spectrometry (HRMS), elemental analysis, and examined as catalysts for oxidative lactonization of 1,4- and 1,5-diols. Oxidative lactonization of 1,4-butanediol to afford γ-butyrolactone proceeded selectively and efficiently using [(η5-Me4C5R)IrCl]2(μ2-Cl)2 as the catalyst. Several R substituents were tested to assess electronic substituent effects. The most active complex contained an electron donating group, R = CHMe2 and successfully catalyzed the formation of diols to lactones across a range of 1,4- and 1,5-diols, generally in high yield. Computational analysis of the rate-determining b-hydrogen elimination reactions provided an atomistic account of observed trends in reaction yield and selectivity as a function of substrate structure, while accounting neatly for the observed selective formation of lactones (vs. succinaldehyde) in the transfer dehydrogenation of 1,4-butyrolactone."],"dc:description.abstractgeneral":["Rhodium(III) and iridium(III) complexes are useful synthetic precursors, catalysts, and biologically active compounds. This dissertation explores a rapid synthesis of these metal complexes and their subsequent catalytic applications with 1,4- and 1,5-diols. The oxidative lactonization of diols with rhodium and iridium complexes is an attractive one-pot synthesis, opening a variety of lactones to be produced. Structural studies involving novel fluorinated rhodium and iridium chloro-bridged dimers are discussed in detail."],"dc:description.degree":["Doctor of Philosophy"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:21089"],"dc:identifier.uri":["http://hdl.handle.net/10919/89732"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["iridium","rhodium","lactone","oxidative lactonization","transfer dehydrogenation","microwave synthesis","ligand effects"],"dc:title":["Rapid Synthesis, Characterization, and Catalytic Function of Rhodium(III) and Iridium(III) Chloro-bridged Dimers"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:52Z"}