{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/84187"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/84187","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Folding-Promoted Reactivity and Tunable Structure of Pyridine-Containing M-Phenylene Ethynylene Helical Cavitands","abstract":"In one study, a hydrogen bonding interaction between adjacent monomer units is shown to stabilize the folded conformation of a PE oligomer. Subsequent studies focus on the incorporation of pyridine rings into the chain sequence. The pKa value of the pyridine nitrogen can be modulated either by changing the substituents on the pyridine ring, or in some cases, through noncovalent interactions in the folded helical structure. When the pyridine ring bears a N,N-dimethylamino substituent, the folded structure of the oligomer is shown to promote methylation of the pyridine nitrogen. The lowered energy barrier for this reaction results from binding of the methylating agent in the helical cavity of the oligomer, where it is constrained in close proximity to the pyridine nucleophile. Also, methylation of the pyridine ring is shown to stabilize the folded conformation of the oligomers through pyridinium-pi interactions. Together, these studies represent progress toward the design of functionalized PE oligomers for use as supramolecular catalysts.","abstract_html":"In one study, a hydrogen bonding interaction between adjacent monomer units is shown to stabilize the folded conformation of a PE oligomer. Subsequent studies focus on the incorporation of pyridine rings into the chain sequence. The pKa value of the pyridine nitrogen can be modulated either by changing the substituents on the pyridine ring, or in some cases, through noncovalent interactions in the folded helical structure. When the pyridine ring bears a N,N-dimethylamino substituent, the folded structure of the oligomer is shown to promote methylation of the pyridine nitrogen. The lowered energy barrier for this reaction results from binding of the methylating agent in the helical cavity of the oligomer, where it is constrained in close proximity to the pyridine nucleophile. Also, methylation of the pyridine ring is shown to stabilize the folded conformation of the oligomers through pyridinium-pi interactions. Together, these studies represent progress toward the design of functionalized PE oligomers for use as supramolecular catalysts.","abstract_has_math":false,"creators":["Heemstra, Jennifer Margaret"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemistry","degree_department":null,"school":null,"contributors":["Moore, Jeffrey S."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T22:13:23Z","date_published":"2015-09-25T22:13:23Z","updated_at":"2026-07-22T22:26:22Z","subjects":["Chemistry, Organic"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3199018"],"render_values":[{"text":"(MiAaPQ)AAI3199018","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/84187","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Moore, Jeffrey S."]},{"key":"dc:creator","label":"Author","values":["Heemstra, Jennifer Margaret"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T22:13:23Z","10000-01-01","2005"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Organic"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/84187","(MiAaPQ)AAI3199018"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In one study, a hydrogen bonding interaction between adjacent monomer units is shown to stabilize the folded conformation of a PE oligomer. Subsequent studies focus on the incorporation of pyridine rings into the chain sequence. The pKa value of the pyridine nitrogen can be modulated either by changing the substituents on the pyridine ring, or in some cases, through noncovalent interactions in the folded helical structure. When the pyridine ring bears a N,N-dimethylamino substituent, the folded structure of the oligomer is shown to promote methylation of the pyridine nitrogen. The lowered energy barrier for this reaction results from binding of the methylating agent in the helical cavity of the oligomer, where it is constrained in close proximity to the pyridine nucleophile. Also, methylation of the pyridine ring is shown to stabilize the folded conformation of the oligomers through pyridinium-pi interactions. Together, these studies represent progress toward the design of functionalized PE oligomers for use as supramolecular catalysts.","Made available in DSpace on 2015-09-25T22:13:23Z (GMT). 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Subsequent studies focus on the incorporation of pyridine rings into the chain sequence. The pKa value of the pyridine nitrogen can be modulated either by changing the substituents on the pyridine ring, or in some cases, through noncovalent interactions in the folded helical structure. When the pyridine ring bears a N,N-dimethylamino substituent, the folded structure of the oligomer is shown to promote methylation of the pyridine nitrogen. The lowered energy barrier for this reaction results from binding of the methylating agent in the helical cavity of the oligomer, where it is constrained in close proximity to the pyridine nucleophile. Also, methylation of the pyridine ring is shown to stabilize the folded conformation of the oligomers through pyridinium-pi interactions. Together, these studies represent progress toward the design of functionalized PE oligomers for use as supramolecular catalysts.","Made available in DSpace on 2015-09-25T22:13:23Z (GMT). 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