{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/84387"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/84387","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Solvophobically-Driven Folding of Non-Biological Oligomers and the Solid Phase Synthesis of Phenylacetylene Oligomers","abstract":"The ordered sequence of monomers in phenylacetylene oligomers can serve as a repeating motif to produce helical structures in solution which posses a tubular cavity. Calculations with modest size oligomers show stable helical conformations with as few as 8 monomer units. Oligomers with triglyme monomethyl ether benzoate functionalized monomers (R = -COO(CH$\\rm\\sb2CH\\sb2O)\\sb3CH\\sb3)$ reveal dramatic chain-length-dependent aromatic chemical shifting in CD$\\sb3$CN, indicative of aromatic stacking and helical structure. In addition. when chain length reaches 12 monomer units, oligomers begin to strongly aggregate which may be a result of helical oligomers associating like their corresponding macrocycles in a face-to-face parallel fashion. Chain length dependence of UV/Vis and $\\sp1$H NMR spectra provide strong evidence of the ordering of monomers and intramolecular aromatic stacking which is consistent with the formation of helical structures. Using UV/Vis absorption at 303 nm as an indication of helical structure, reversible thermal helix-coil transitions were measured in 4/6, $\\rm CH\\sb3CN/CHCl\\sb3.$ In agreement with the calculations, the octadecamer possesses the largest shift in $\\rm\\delta\\sb{A},$ the best resolved $\\sp1$H NMR spectra of the oligomers longer than 12 monomers, and the largest hypochromic shift at 303 nm which is attributed to intramolecular aromatic stacking.","abstract_html":"The ordered sequence of monomers in phenylacetylene oligomers can serve as a repeating motif to produce helical structures in solution which posses a tubular cavity. Calculations with modest size oligomers show stable helical conformations with as few as 8 monomer units. Oligomers with triglyme monomethyl ether benzoate functionalized monomers (R = -COO(CH$\\rm\\sb2CH\\sb2O)\\sb3CH\\sb3)$ reveal dramatic chain-length-dependent aromatic chemical shifting in CD$\\sb3$CN, indicative of aromatic stacking and helical structure. In addition. when chain length reaches 12 monomer units, oligomers begin to strongly aggregate which may be a result of helical oligomers associating like their corresponding macrocycles in a face-to-face parallel fashion. Chain length dependence of UV/Vis and $\\sp1$H NMR spectra provide strong evidence of the ordering of monomers and intramolecular aromatic stacking which is consistent with the formation of helical structures. Using UV/Vis absorption at 303 nm as an indication of helical structure, reversible thermal helix-coil transitions were measured in 4/6, $\\rm CH\\sb3CN/CHCl\\sb3.$ In agreement with the calculations, the octadecamer possesses the largest shift in <span class=\"etd-inline-math\">\\rm&delta;\\sb{A},</span> the best resolved $\\sp1$H NMR spectra of the oligomers longer than 12 monomers, and the largest hypochromic shift at 303 nm which is attributed to intramolecular aromatic stacking.","abstract_has_math":true,"creators":["Nelson, James Curtis"],"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":"2015-09-25T22:14:15Z","date_published":"2015-09-25T22:14:15Z","updated_at":"2026-07-22T22:26:23Z","subjects":["Chemistry, Polymer"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9812719"],"render_values":[{"text":"(MiAaPQ)AAI9812719","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/84387","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":["Nelson, James Curtis"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T22:14:15Z","10000-01-01","1997"]},{"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, Polymer"]}]},{"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/2142/84387","(MiAaPQ)AAI9812719"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The ordered sequence of monomers in phenylacetylene oligomers can serve as a repeating motif to produce helical structures in solution which posses a tubular cavity. Calculations with modest size oligomers show stable helical conformations with as few as 8 monomer units. Oligomers with triglyme monomethyl ether benzoate functionalized monomers (R = -COO(CH$\\rm\\sb2CH\\sb2O)\\sb3CH\\sb3)$ reveal dramatic chain-length-dependent aromatic chemical shifting in CD$\\sb3$CN, indicative of aromatic stacking and helical structure. In addition. when chain length reaches 12 monomer units, oligomers begin to strongly aggregate which may be a result of helical oligomers associating like their corresponding macrocycles in a face-to-face parallel fashion. Chain length dependence of UV/Vis and $\\sp1$H NMR spectra provide strong evidence of the ordering of monomers and intramolecular aromatic stacking which is consistent with the formation of helical structures. Using UV/Vis absorption at 303 nm as an indication of helical structure, reversible thermal helix-coil transitions were measured in 4/6, $\\rm CH\\sb3CN/CHCl\\sb3.$ In agreement with the calculations, the octadecamer possesses the largest shift in $\\rm\\delta\\sb{A},$ the best resolved $\\sp1$H NMR spectra of the oligomers longer than 12 monomers, and the largest hypochromic shift at 303 nm which is attributed to intramolecular aromatic stacking.","Made available in DSpace on 2015-09-25T22:14:15Z (GMT). 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Calculations with modest size oligomers show stable helical conformations with as few as 8 monomer units. Oligomers with triglyme monomethyl ether benzoate functionalized monomers (R = -COO(CH$\\rm\\sb2CH\\sb2O)\\sb3CH\\sb3)$ reveal dramatic chain-length-dependent aromatic chemical shifting in CD$\\sb3$CN, indicative of aromatic stacking and helical structure. In addition. when chain length reaches 12 monomer units, oligomers begin to strongly aggregate which may be a result of helical oligomers associating like their corresponding macrocycles in a face-to-face parallel fashion. Chain length dependence of UV/Vis and $\\sp1$H NMR spectra provide strong evidence of the ordering of monomers and intramolecular aromatic stacking which is consistent with the formation of helical structures. Using UV/Vis absorption at 303 nm as an indication of helical structure, reversible thermal helix-coil transitions were measured in 4/6, $\\rm CH\\sb3CN/CHCl\\sb3.$ In agreement with the calculations, the octadecamer possesses the largest shift in $\\rm\\delta\\sb{A},$ the best resolved $\\sp1$H NMR spectra of the oligomers longer than 12 monomers, and the largest hypochromic shift at 303 nm which is attributed to intramolecular aromatic stacking.","Made available in DSpace on 2015-09-25T22:14:15Z (GMT). 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