{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/113162"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/113162","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Highly efficient macrocycle and cage formation via hindered urea chemistry","abstract":"U of I Only","abstract_html":"U of I Only","abstract_has_math":false,"creators":["Yang, Yingfeng"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Cheng, Jianjun","Zimmerman, Steven C.","Chen, Qian","Evans, Christopher"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-01-12T22:35:07Z","date_published":"2022-01-12T22:35:07Z","updated_at":"2026-07-22T22:24:53Z","subjects":["Dynamic covalent chemistry","hindered urea bond","de-tert-butytlation","hindered urea macrocycles","cis-urea preference","quantitative synthesis","cyclic peptides","urea cages","adsorptive separation"],"languages":["en"],"rights":["Copyright 2021 Yingfeng Yang"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/113162","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Cheng, Jianjun","Zimmerman, Steven C.","Chen, Qian","Evans, Christopher"]},{"key":"dc:creator","label":"Author","values":["Yang, Yingfeng"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-01-12T22:35:07Z","2024-01-12T22:35:30Z","2021-07-14","2021-08"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science & Engr"]},{"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":["Dynamic covalent chemistry","hindered urea bond","de-tert-butytlation","hindered urea macrocycles","cis-urea preference","quantitative synthesis","cyclic peptides","urea cages","adsorptive separation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2021 Yingfeng Yang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/113162"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["U of I Only","Dynamic covalent chemistry (DCC) is a powerful tool that enables the synthesis of novel macrocycles, molecular cages, knots and frameworks, as well as the development of dynamic polymeric materials with unique properties. Hindered urea bond (HUB), a newly developed DCC, has found applications in dynamic materials designs such as self-healing, malleable, shape-memory or environmentally-adaptive materials. However, despite of the intensive research, study of this new, facile dynamic chemistry is still in its infancy. The potential of HUB in the formation of discrete structures in small molecular level is largely overlooked and not demonstrated. What’s more, a turning-off mechanism for HUB was not found which can severally limit the applications of HUB-based materials. Here we report the discovery of acid-assisted de-tert-butylation reaction that can instantly “turn off” the dynamicity of HUB, leading to improved chemical stabilities and mechanical properties of HUB-containing materials. We also demonstrated the use of dynamic HUB for the construction of urea macrocycles with very high efficiency. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C=O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. Building upon the macrocyclization mechanism, we demonstrated that HUB can function as efficient cyclization enabling motif for cyclic peptides. Beyond macrocycles, HUB was also utilized to efficiently construct a series of structures with different topologies as well as urea cages, which were demonstrated to be able to separate important petrochemicals such as pyridine/toluene and benzene/cyclohexane.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-08-01","The student, Yingfeng Yang, accepted the attached license on 2021-07-09 at 04:30.","The student, Yingfeng Yang, submitted this Dissertation for approval on 2021-07-09 at 05:03.","This Dissertation was approved for publication on 2021-07-14 at 15:30.","DSpace SAF Submission Ingestion Package generated from Vireo submission #16816 on 2022-01-12 at 12:54:04","Made available in DSpace on 2022-01-12T22:35:07Z (GMT). No. of bitstreams: 2 YANG-DISSERTATION-2021.pdf: 13062445 bytes, checksum: 802675cec9adbb471f8524d5c5833390 (MD5) LICENSE.txt: 4210 bytes, checksum: f2b954cd3363d1b02e07591b4d3d83c5 (MD5) Previous issue date: 2021-07-14","Embargo set by: Seth Robbins for item 121088 Lift date: 2024-01-12T22:35:30Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Highly efficient macrocycle and cage formation via hindered urea chemistry"]}]}],"canonical_facts":{"dc:contributor":["Cheng, Jianjun","Zimmerman, Steven C.","Chen, Qian","Evans, Christopher"],"dc:creator":["Yang, Yingfeng"],"dc:date":["2022-01-12T22:35:07Z","2024-01-12T22:35:30Z","2021-07-14","2021-08"],"dc:description":["U of I Only","Dynamic covalent chemistry (DCC) is a powerful tool that enables the synthesis of novel macrocycles, molecular cages, knots and frameworks, as well as the development of dynamic polymeric materials with unique properties. Hindered urea bond (HUB), a newly developed DCC, has found applications in dynamic materials designs such as self-healing, malleable, shape-memory or environmentally-adaptive materials. However, despite of the intensive research, study of this new, facile dynamic chemistry is still in its infancy. The potential of HUB in the formation of discrete structures in small molecular level is largely overlooked and not demonstrated. What’s more, a turning-off mechanism for HUB was not found which can severally limit the applications of HUB-based materials. Here we report the discovery of acid-assisted de-tert-butylation reaction that can instantly “turn off” the dynamicity of HUB, leading to improved chemical stabilities and mechanical properties of HUB-containing materials. We also demonstrated the use of dynamic HUB for the construction of urea macrocycles with very high efficiency. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C=O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. Building upon the macrocyclization mechanism, we demonstrated that HUB can function as efficient cyclization enabling motif for cyclic peptides. Beyond macrocycles, HUB was also utilized to efficiently construct a series of structures with different topologies as well as urea cages, which were demonstrated to be able to separate important petrochemicals such as pyridine/toluene and benzene/cyclohexane.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-08-01","The student, Yingfeng Yang, accepted the attached license on 2021-07-09 at 04:30.","The student, Yingfeng Yang, submitted this Dissertation for approval on 2021-07-09 at 05:03.","This Dissertation was approved for publication on 2021-07-14 at 15:30.","DSpace SAF Submission Ingestion Package generated from Vireo submission #16816 on 2022-01-12 at 12:54:04","Made available in DSpace on 2022-01-12T22:35:07Z (GMT). No. of bitstreams: 2 YANG-DISSERTATION-2021.pdf: 13062445 bytes, checksum: 802675cec9adbb471f8524d5c5833390 (MD5) LICENSE.txt: 4210 bytes, checksum: f2b954cd3363d1b02e07591b4d3d83c5 (MD5) Previous issue date: 2021-07-14","Embargo set by: Seth Robbins for item 121088 Lift date: 2024-01-12T22:35:30Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/113162"],"dc:language":["en"],"dc:rights":["Copyright 2021 Yingfeng Yang"],"dc:subject":["Dynamic covalent chemistry","hindered urea bond","de-tert-butytlation","hindered urea macrocycles","cis-urea preference","quantitative synthesis","cyclic peptides","urea cages","adsorptive separation"],"dc:title":["Highly efficient macrocycle and cage formation via hindered urea chemistry"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Materials Science & Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:53Z"}