{"id":{"repo_id":"alabama","oai_identifier":"oai:ir.ua.edu:123456789/7650"},"canonical_url":"https://search.dev.ndltd.org/etd/alabama/oai:ir.ua.edu:123456789/7650","repository":{"repo_id":"alabama","name":"University of Alabama","base_url":"https://ir-api.ua.edu/oai/request"},"display":{"title":"Enhancing thermal isomerization rates of redox auxiliary-appended azobenzenes via redox auxiliary catalysis","abstract":"Azobenzene exists in E or Z isomeric forms having different three-dimensional structures, chemical properties, optical properties and electronic properties. Azobenzene can switch between E and Z conformations using light and has been incorporated in chemical systems to impart photoswitchable characteristics. Thermal conversion from the Z to E often occurs slowly and is unideal when fast dynamics is desired. ZE photoswitching is typically incomplete, leaving a significant percentage of molecules in the Z conformation. The Blackstock group has covalently attached an easily oxidized aryl amine “redox auxiliary” (RA) to the azobenzene scaffold to facilitate rapid and complete ZE conversion by adding a catalytic amount of oxidant. We hypothesize that the oxidized Z isomer of a RA-appended azobenzene (RA-azo) will rapidly isomerize to the E conformation because oxidizing the RA greatly reduces the energetic barrier to ZE isomerization. The newly formed (E) RA•+ azo molecule will oxidize a neutral (Z) RA azo, generating a (Z) RA•+ azo radical cation. This (Z) RA•+ azo will undergo rapid ZE isomerization to yield another (E) RA•+ azo molecule, which will oxidize another neutral (Z) RA azo. To increase the electron catalysis turnover number, we incorporated a new RA. This new RA-azo underwent complete and rapid ZE switching using a lower electrocatalytic loading than other RA-azos previously studied. Rapid ZE conversion was also achieved in a photo-electrical cell device (PED), and several EZE switching cycles were achieved using light and voltage in tandem. Attaching two azobenzene moieties to the new RA allowed for electrocatalytic ZE switching of both moieties. The azobenzene ZE thermal isomerization half-life is ~2 days, but adding the RA (or most other substituents) reduces this half-life to hours or minutes. By developing an RA-azo with ortho fluorines, we produced an RA-azo exhbiting an exceptionally long half-life (t1/2 = 40 days) and the capability to undergo rapid and complete ZE switching upon addition of 0.11 mol% oxidant. This results in a 6,900,000 fold ZE rate acceleration. Extrapolating to the case of 100 mol% oxidant gives a 6,300,000,000 fold ZE rate acceleration, which is by far the greatest RA-facilitated ZE rate acceleration observed for any RA-azo studied by the Blackstock group to date.","abstract_html":"Azobenzene exists in E or Z isomeric forms having different three-dimensional structures, chemical properties, optical properties and electronic properties. Azobenzene can switch between E and Z conformations using light and has been incorporated in chemical systems to impart photoswitchable characteristics. Thermal conversion from the Z to E often occurs slowly and is unideal when fast dynamics is desired. ZE photoswitching is typically incomplete, leaving a significant percentage of molecules in the Z conformation. The Blackstock group has covalently attached an easily oxidized aryl amine “redox auxiliary” (RA) to the azobenzene scaffold to facilitate rapid and complete ZE conversion by adding a catalytic amount of oxidant. We hypothesize that the oxidized Z isomer of a RA-appended azobenzene (RA-azo) will rapidly isomerize to the E conformation because oxidizing the RA greatly reduces the energetic barrier to ZE isomerization. The newly formed (E) RA•+ azo molecule will oxidize a neutral (Z) RA azo, generating a (Z) RA•+ azo radical cation. This (Z) RA•+ azo will undergo rapid ZE isomerization to yield another (E) RA•+ azo molecule, which will oxidize another neutral (Z) RA azo. To increase the electron catalysis turnover number, we incorporated a new RA. This new RA-azo underwent complete and rapid ZE switching using a lower electrocatalytic loading than other RA-azos previously studied. Rapid ZE conversion was also achieved in a photo-electrical cell device (PED), and several EZE switching cycles were achieved using light and voltage in tandem. Attaching two azobenzene moieties to the new RA allowed for electrocatalytic ZE switching of both moieties. The azobenzene ZE thermal isomerization half-life is ~2 days, but adding the RA (or most other substituents) reduces this half-life to hours or minutes. By developing an RA-azo with ortho fluorines, we produced an RA-azo exhbiting an exceptionally long half-life (t1/2 = 40 days) and the capability to undergo rapid and complete ZE switching upon addition of 0.11 mol% oxidant. This results in a 6,900,000 fold ZE rate acceleration. Extrapolating to the case of 100 mol% oxidant gives a 6,300,000,000 fold ZE rate acceleration, which is by far the greatest RA-facilitated ZE rate acceleration observed for any RA-azo studied by the Blackstock group to date.","abstract_has_math":false,"creators":["Warner, David James"],"institution":"University of Alabama Libraries","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Jennings, Michael P.","LeClair, Patrick R.","Pan, Shanlin","Shaughnessy, Kevin H."],"advisors":["Blackstock, Silas C."],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-08","date_published":"2020-08","updated_at":"2026-07-27T18:44:27Z","subjects":["Organic chemistry"],"languages":["en_US","English"],"rights":["All rights reserved by the author unless otherwise indicated."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["u0015_0000001_0003707","Warner_alatus_0004D_14077"],"render_values":[{"text":"u0015_0000001_0003707","href":null,"code":true},{"text":"Warner_alatus_0004D_14077","href":null,"code":true}]}]},"links":{"outbound_url":"http://ir.ua.edu/handle/123456789/7650","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Jennings, Michael P.","LeClair, Patrick R.","Pan, Shanlin","Shaughnessy, Kevin H."]},{"key":"dc:contributor.advisor","label":"Advisor","values":["Blackstock, Silas C."]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["University of Alabama Tuscaloosa"]},{"key":"dc:creator","label":"Author","values":["Warner, David James"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2021-05-12T16:28:15Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2021-05-12T16:28:15Z"]},{"key":"dc:date.issued","label":"Date","values":["2020-08"]},{"key":"dc:publisher","label":"Institution","values":["University of Alabama Libraries"]},{"key":"dc:type","label":"Dc Type","values":["thesis","text"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Organic chemistry"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]},{"key":"dc:rights","label":"Dc Rights","values":["All rights reserved by the author unless otherwise indicated."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["u0015_0000001_0003707","Warner_alatus_0004D_14077"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://ir.ua.edu/handle/123456789/7650"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Electronic Thesis or Dissertation"]},{"key":"dc:description.abstract","label":"Abstract","values":["Azobenzene exists in E or Z isomeric forms having different three-dimensional structures, chemical properties, optical properties and electronic properties. Azobenzene can switch between E and Z conformations using light and has been incorporated in chemical systems to impart photoswitchable characteristics. Thermal conversion from the Z to E often occurs slowly and is unideal when fast dynamics is desired. ZE photoswitching is typically incomplete, leaving a significant percentage of molecules in the Z conformation. The Blackstock group has covalently attached an easily oxidized aryl amine “redox auxiliary” (RA) to the azobenzene scaffold to facilitate rapid and complete ZE conversion by adding a catalytic amount of oxidant. We hypothesize that the oxidized Z isomer of a RA-appended azobenzene (RA-azo) will rapidly isomerize to the E conformation because oxidizing the RA greatly reduces the energetic barrier to ZE isomerization. The newly formed (E) RA•+ azo molecule will oxidize a neutral (Z) RA azo, generating a (Z) RA•+ azo radical cation. This (Z) RA•+ azo will undergo rapid ZE isomerization to yield another (E) RA•+ azo molecule, which will oxidize another neutral (Z) RA azo. To increase the electron catalysis turnover number, we incorporated a new RA. This new RA-azo underwent complete and rapid ZE switching using a lower electrocatalytic loading than other RA-azos previously studied. Rapid ZE conversion was also achieved in a photo-electrical cell device (PED), and several EZE switching cycles were achieved using light and voltage in tandem. Attaching two azobenzene moieties to the new RA allowed for electrocatalytic ZE switching of both moieties. The azobenzene ZE thermal isomerization half-life is ~2 days, but adding the RA (or most other substituents) reduces this half-life to hours or minutes. By developing an RA-azo with ortho fluorines, we produced an RA-azo exhbiting an exceptionally long half-life (t1/2 = 40 days) and the capability to undergo rapid and complete ZE switching upon addition of 0.11 mol% oxidant. This results in a 6,900,000 fold ZE rate acceleration. Extrapolating to the case of 100 mol% oxidant gives a 6,300,000,000 fold ZE rate acceleration, which is by far the greatest RA-facilitated ZE rate acceleration observed for any RA-azo studied by the Blackstock group to date."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["electronic"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Enhancing thermal isomerization rates of redox auxiliary-appended azobenzenes via redox auxiliary catalysis"]}]}],"canonical_facts":{"dc:contributor":["Jennings, Michael P.","LeClair, Patrick R.","Pan, Shanlin","Shaughnessy, Kevin H."],"dc:contributor.advisor":["Blackstock, Silas C."],"dc:contributor.other":["University of Alabama Tuscaloosa"],"dc:creator":["Warner, David James"],"dc:date.accessioned":["2021-05-12T16:28:15Z"],"dc:date.available":["2021-05-12T16:28:15Z"],"dc:date.issued":["2020-08"],"dc:description":["Electronic Thesis or Dissertation"],"dc:description.abstract":["Azobenzene exists in E or Z isomeric forms having different three-dimensional structures, chemical properties, optical properties and electronic properties. Azobenzene can switch between E and Z conformations using light and has been incorporated in chemical systems to impart photoswitchable characteristics. Thermal conversion from the Z to E often occurs slowly and is unideal when fast dynamics is desired. ZE photoswitching is typically incomplete, leaving a significant percentage of molecules in the Z conformation. The Blackstock group has covalently attached an easily oxidized aryl amine “redox auxiliary” (RA) to the azobenzene scaffold to facilitate rapid and complete ZE conversion by adding a catalytic amount of oxidant. We hypothesize that the oxidized Z isomer of a RA-appended azobenzene (RA-azo) will rapidly isomerize to the E conformation because oxidizing the RA greatly reduces the energetic barrier to ZE isomerization. The newly formed (E) RA•+ azo molecule will oxidize a neutral (Z) RA azo, generating a (Z) RA•+ azo radical cation. This (Z) RA•+ azo will undergo rapid ZE isomerization to yield another (E) RA•+ azo molecule, which will oxidize another neutral (Z) RA azo. To increase the electron catalysis turnover number, we incorporated a new RA. This new RA-azo underwent complete and rapid ZE switching using a lower electrocatalytic loading than other RA-azos previously studied. Rapid ZE conversion was also achieved in a photo-electrical cell device (PED), and several EZE switching cycles were achieved using light and voltage in tandem. Attaching two azobenzene moieties to the new RA allowed for electrocatalytic ZE switching of both moieties. The azobenzene ZE thermal isomerization half-life is ~2 days, but adding the RA (or most other substituents) reduces this half-life to hours or minutes. By developing an RA-azo with ortho fluorines, we produced an RA-azo exhbiting an exceptionally long half-life (t1/2 = 40 days) and the capability to undergo rapid and complete ZE switching upon addition of 0.11 mol% oxidant. This results in a 6,900,000 fold ZE rate acceleration. Extrapolating to the case of 100 mol% oxidant gives a 6,300,000,000 fold ZE rate acceleration, which is by far the greatest RA-facilitated ZE rate acceleration observed for any RA-azo studied by the Blackstock group to date."],"dc:format.medium":["electronic"],"dc:format.mimetype":["application/pdf"],"dc:identifier.other":["u0015_0000001_0003707","Warner_alatus_0004D_14077"],"dc:identifier.uri":["http://ir.ua.edu/handle/123456789/7650"],"dc:language":["English"],"dc:language.iso":["en_US"],"dc:publisher":["University of Alabama Libraries"],"dc:rights":["All rights reserved by the author unless otherwise indicated."],"dc:subject":["Organic chemistry"],"dc:title":["Enhancing thermal isomerization rates of redox auxiliary-appended azobenzenes via redox auxiliary catalysis"],"dc:type":["thesis","text"]},"updated_at":"2026-07-27T18:44:27Z"}