Proton-Transfer Polymerization by N-Heterocyclic Carbenes: Monomer and Catalyst Scopes and Mechanism for Converting Dimethacrylates into Unsaturated Polyesters

Handle URI:
http://hdl.handle.net/10754/594735
Title:
Proton-Transfer Polymerization by N-Heterocyclic Carbenes: Monomer and Catalyst Scopes and Mechanism for Converting Dimethacrylates into Unsaturated Polyesters
Authors:
Hong, Miao; Tang, Xiaoyan; Falivene, Laura ( 0000-0003-1509-6191 ) ; Caporaso, Lucia; Cavallo, Luigi ( 0000-0002-1398-338X ) ; Chen, Eugene Y.-X.
Abstract:
This contribution presents a full account of experimental and theoretical/computational investigations into the N-heterocyclic carbene (NHC)-catalyzed proton-transfer polymerization (HTP) that converts common dimethacrylates (DMAs) containing no protic groups into unsaturated polyesters. This new HTP proceeds through the step-growth propagation cycles via enamine intermediates, consisting of the proposed conjugate addition–proton transfer–NHC release fundamental steps. This study examines the monomer and catalyst scopes as well as the fundamental steps involved in the overall HTP mechanism. DMAs having six different types of linkages connecting the two methacrylates have been polymerized into the corresponding unsaturated polyesters. The most intriguing unsaturated polyester of the series is that based on the biomass-derived furfuryl dimethacrylate, which showed a unique self-curing ability Four MeO– and Cl–substituted TPT (1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene) derivatives as methanol insertion products, RxTPT(MeO/H) (R = MeO, Cl; x = 2, 3), and two free carbenes (catalysts), OMe2TPT and OMe3TPT, have been synthesized, while OMe2TPT(MeO/H) and OMe2TPT have also been structurally characterized. The structure/reactivity relationship study revealed that OMe2TPT, being both a strong nucleophile and a good leaving group, exhibits the highest HTP activity and also produced the polyester with the highest Mn, while the Cl–substituted TPT derivatives are least active and efficient. Computational studies have provided mechanistic insights into the tail-to-tail dimerization coupling step as a suitable model for the propagation cycle of the HTP. The extensive energy profile was mapped out and the experimentally observed unicity of the TPT-based catalysts was satisfactorily explained with the thermodynamic formation of key spirocyclic species.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; KAUST Catalysis Center (KCC)
Citation:
Proton-Transfer Polymerization by N-Heterocyclic Carbenes: Monomer and Catalyst Scopes and Mechanism for Converting Dimethacrylates into Unsaturated Polyesters 2016 Journal of the American Chemical Society
Publisher:
American Chemical Society (ACS)
Journal:
Journal of the American Chemical Society
Issue Date:
18-Jan-2016
DOI:
10.1021/jacs.5b13019
Type:
Article
ISSN:
0002-7863; 1520-5126
Is Supplemented By:
Hong, M., Tang, X., Falivene, L., Caporaso, L., Cavallo, L., & Chen, E. Y.-X. (2016). CCDC 1441030: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc1kchv8; DOI:10.5517/cc1kchv8; HANDLE:http://hdl.handle.net/10754/624488; Hong, M., Tang, X., Falivene, L., Caporaso, L., Cavallo, L., & Chen, E. Y.-X. (2016). CCDC 1441032: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc1kchxb; DOI:10.5517/cc1kchxb; HANDLE:http://hdl.handle.net/10754/624489
Additional Links:
http://pubs.acs.org/doi/10.1021/jacs.5b13019
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorHong, Miaoen
dc.contributor.authorTang, Xiaoyanen
dc.contributor.authorFalivene, Lauraen
dc.contributor.authorCaporaso, Luciaen
dc.contributor.authorCavallo, Luigien
dc.contributor.authorChen, Eugene Y.-X.en
dc.date.accessioned2016-01-24T10:26:13Zen
dc.date.available2016-01-24T10:26:13Zen
dc.date.issued2016-01-18en
dc.identifier.citationProton-Transfer Polymerization by N-Heterocyclic Carbenes: Monomer and Catalyst Scopes and Mechanism for Converting Dimethacrylates into Unsaturated Polyesters 2016 Journal of the American Chemical Societyen
dc.identifier.issn0002-7863en
dc.identifier.issn1520-5126en
dc.identifier.doi10.1021/jacs.5b13019en
dc.identifier.urihttp://hdl.handle.net/10754/594735en
dc.description.abstractThis contribution presents a full account of experimental and theoretical/computational investigations into the N-heterocyclic carbene (NHC)-catalyzed proton-transfer polymerization (HTP) that converts common dimethacrylates (DMAs) containing no protic groups into unsaturated polyesters. This new HTP proceeds through the step-growth propagation cycles via enamine intermediates, consisting of the proposed conjugate addition–proton transfer–NHC release fundamental steps. This study examines the monomer and catalyst scopes as well as the fundamental steps involved in the overall HTP mechanism. DMAs having six different types of linkages connecting the two methacrylates have been polymerized into the corresponding unsaturated polyesters. The most intriguing unsaturated polyester of the series is that based on the biomass-derived furfuryl dimethacrylate, which showed a unique self-curing ability Four MeO– and Cl–substituted TPT (1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene) derivatives as methanol insertion products, RxTPT(MeO/H) (R = MeO, Cl; x = 2, 3), and two free carbenes (catalysts), OMe2TPT and OMe3TPT, have been synthesized, while OMe2TPT(MeO/H) and OMe2TPT have also been structurally characterized. The structure/reactivity relationship study revealed that OMe2TPT, being both a strong nucleophile and a good leaving group, exhibits the highest HTP activity and also produced the polyester with the highest Mn, while the Cl–substituted TPT derivatives are least active and efficient. Computational studies have provided mechanistic insights into the tail-to-tail dimerization coupling step as a suitable model for the propagation cycle of the HTP. The extensive energy profile was mapped out and the experimentally observed unicity of the TPT-based catalysts was satisfactorily explained with the thermodynamic formation of key spirocyclic species.en
dc.language.isoenen
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/10.1021/jacs.5b13019en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/10.1021/jacs.5b13019.en
dc.titleProton-Transfer Polymerization by N-Heterocyclic Carbenes: Monomer and Catalyst Scopes and Mechanism for Converting Dimethacrylates into Unsaturated Polyestersen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.identifier.journalJournal of the American Chemical Societyen
dc.eprint.versionPost-printen
dc.contributor.institutionDepartment of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USAen
dc.contributor.institutionDipartimento di Chimica e Biologia, Università di Salerno, Via Papa Paolo Giovanni II, I-84084, Fisciano, Italyen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorFalivene, Lauraen
kaust.authorCavallo, Luigien
dc.relation.isSupplementedByHong, M., Tang, X., Falivene, L., Caporaso, L., Cavallo, L., & Chen, E. Y.-X. (2016). CCDC 1441030: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc1kchv8en
dc.relation.isSupplementedByDOI:10.5517/cc1kchv8en
dc.relation.isSupplementedByHANDLE:http://hdl.handle.net/10754/624488en
dc.relation.isSupplementedByHong, M., Tang, X., Falivene, L., Caporaso, L., Cavallo, L., & Chen, E. Y.-X. (2016). CCDC 1441032: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc1kchxben
dc.relation.isSupplementedByDOI:10.5517/cc1kchxben
dc.relation.isSupplementedByHANDLE:http://hdl.handle.net/10754/624489en
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