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Mizerska U, Rubinsztajn S, Chojnowski J, Cypryk M, Uznanski P, Walkiewicz-Pietrzykowska A, Fortuniak W. Self-Restructuring of Polyhydromethylsiloxanes by the Hydride Transfer Process: A New Approach to the Cross-Linking of Polysiloxanes and to the Fabrication of Thin Polysiloxane Coatings. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6981. [PMID: 36234320 PMCID: PMC9570814 DOI: 10.3390/ma15196981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
The branching and cross-linking of siloxane polymers are important processes in silicone technology. A new type of such a process has been developed, which is a self-restructuring of linear polyhydromethylsiloxane (PHMS). This process involves the reorganization of the PHMS to form a highly branched siloxane polymer or finally a cross-linked siloxane network. It occurs through the transfer of a hydride ion between silicon atoms catalyzed by tris(pentafluoromethyl)borane. Its advantage over existing branching and cross-linking reactions is that it runs at room temperature without a low-molecular-weight cross-linker in the absence of water, silanol groups, or other protic compounds and it does not use metal catalysts. The study of this process was carried out in toluene solution. Its course was followed by 1H NMR, 29Si NMR and FTIR, SEC, and gas chromatography. A general mechanism of this new self-restructuring process supported by quantum calculations is proposed. It has been shown that a linear PHMS self-restructured to a highly branched polymer can serve as a pure methylsiloxane film precursor.
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Balzade Z, Sharif F, Ghaffarian Anbaran SR. Tailor-Made Functional Polyolefins of Complex Architectures: Recent Advances, Applications, and Prospects. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zahra Balzade
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran 158754413, Iran
| | - Farhad Sharif
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran 158754413, Iran
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Teator AJ, Varner TP, Knutson PC, Sorensen CC, Leibfarth FA. 100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization. ACS Macro Lett 2020; 9:1638-1654. [PMID: 35617075 DOI: 10.1021/acsmacrolett.0c00664] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The thermomechanical properties exhibited by synthetic macromolecules can be directly linked to their tacticity, or the relative stereochemistry of repeat units. The development of stereoselective coordination-insertion polymerization, for example, led to the discovery of isotactic polypropylene, now one of the most widely produced commodity plastics in the world. Widespread interest in controlling polymer tacticity has led to a variety of stereoselective polymerization methodologies; however, this area of polymer science has lagged behind when compared to the ability to control molecular weight, dispersity, and composition. Despite decades of advancements, many stereoregular vinyl polymers remain unknown, particularly those comprised of polar functionality or derived from renewable resources. This Viewpoint provides an overview of recent developments in stereocontrolled polymerization, with an emphasis on propagation mechanism, and highlights successes, limitations, and future challenges for continued innovation.
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Affiliation(s)
- Aaron J. Teator
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Travis P. Varner
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Phil C. Knutson
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Cole C. Sorensen
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Frank A. Leibfarth
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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Keyes A, Basbug Alhan HE, Ordonez E, Ha U, Beezer DB, Dau H, Liu Y, Tsogtgerel E, Jones GR, Harth E. Olefins and Vinyl Polar Monomers: Bridging the Gap for Next Generation Materials. Angew Chem Int Ed Engl 2019; 58:12370-12391. [DOI: 10.1002/anie.201900650] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Anthony Keyes
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Hatice E. Basbug Alhan
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Estela Ordonez
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Uyen Ha
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Dain B. Beezer
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Huong Dau
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Yu‐Sheng Liu
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Enkhjargal Tsogtgerel
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Glen R. Jones
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Eva Harth
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
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Keyes A, Basbug Alhan HE, Ordonez E, Ha U, Beezer DB, Dau H, Liu Y, Tsogtgerel E, Jones GR, Harth E. Olefine und polare Vinylmonomere: Überbrückung der Lücke für Materialien der nächsten Generation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201900650] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Anthony Keyes
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Hatice E. Basbug Alhan
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Estela Ordonez
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Uyen Ha
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Dain B. Beezer
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Huong Dau
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Yu‐Sheng Liu
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Enkhjargal Tsogtgerel
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Glen R. Jones
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
| | - Eva Harth
- Department of ChemistryCenter of Excellence in Polymer ChemistryUniversity of Houston 3585 Cullen Boulevard Houston Texas 77030 USA
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Vidal F, Chen EYX. Reactivity of Bridged and Nonbridged Zirconocenes toward Biorenewable Itaconic Esters and Anhydride. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fernando Vidal
- Department of Chemistry, Colorado State University, Fort
Collins, Colorado 80523-1872, United States
| | - Eugene Y.-X. Chen
- Department of Chemistry, Colorado State University, Fort
Collins, Colorado 80523-1872, United States
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Han Y, Zhang S, He J, Zhang Y. B(C6F5)3-Catalyzed (Convergent) Disproportionation Reaction of Indoles. J Am Chem Soc 2017; 139:7399-7407. [DOI: 10.1021/jacs.7b03534] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuxi Han
- State Key Laboratory of Supramolecular
Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012, China
| | - Sutao Zhang
- State Key Laboratory of Supramolecular
Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012, China
| | - Jianghua He
- State Key Laboratory of Supramolecular
Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012, China
| | - Yuetao Zhang
- State Key Laboratory of Supramolecular
Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012, China
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Vidal F, Falivene L, Caporaso L, Cavallo L, Chen EYX. Robust Cross-Linked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization. J Am Chem Soc 2016; 138:9533-47. [PMID: 27388024 DOI: 10.1021/jacs.6b04064] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust cross-linked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site-controlled propagation mechanism. Postfunctionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible cross-linked thin-film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Cross-linking of such complexes affords robust cross-linked stereocomplexes that are solvent-resistant and also exhibit considerably enhanced thermal and mechanical properties compared with the un-cross-linked stereocomplexes.
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Affiliation(s)
- Fernando Vidal
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States
| | - Laura Falivene
- Physical Sciences and Engineering Division, Kaust Catalysis Center, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Lucia Caporaso
- Dipartimento di Chimica e Biologia, Università di Salerno , Via Papa Paolo Giovanni II, I-84084 Fisciano, Italy
| | - Luigi Cavallo
- Physical Sciences and Engineering Division, Kaust Catalysis Center, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Eugene Y-X Chen
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States
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Vidal F, Gowda RR, Chen EYX. Chemoselective, Stereospecific, and Living Polymerization of Polar Divinyl Monomers by Chiral Zirconocenium Catalysts. J Am Chem Soc 2015; 137:9469-80. [PMID: 26153299 DOI: 10.1021/jacs.5b05811] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This contribution reports the first chemoselective, stereospecific, and living polymerization of polar divinyl monomers, enabled by chiral ansa-zirconocenium catalysts through an enantiomorphic-site controlled coordination-addition polymerization mechanism. Silyl-bridged-ansa-zirconocenium ester enolate 2 has been synthesized and structurally characterized, but it exhibits low to negligible activity and stereospecificity in the polymerization of polar divinyl monomers including vinyl methacrylate (VMA), allyl methacrylate (AMA), 4-vinylbenzyl methacrylate (VBMA), and N,N-diallyl acrylamide (DAA). In contrast, ethylene-bridged-ansa-zirconocenium ester enolate 1 is highly active and stereospecific in the polymerization of such monomers including AMA, VBMA, and DAA. The polymerization by 1 is perfectly chemoselective for all four polar divinyl monomers, proceeding exclusively through conjugate addition across the methacrylic C═C bond, while leaving the pendant C═C bonds intact. The polymerization of DAA is most stereospecific and controlled, producing essentially stereoperfect isotactic PDAA with [mmmm] > 99%, M(n) matching the theoretical value (thus a quantitative initiation efficiency), and a narrow molecular weight distribution (Đ = 1.06-1.16). The stereospecificity is slightly lower for the AMA polymerization but still leading to highly isotactic poly(allyl methacrylate) (PAMA) with 95-97% [mm]. The polymerization of VBMA is further less stereospecific, affording PVBMA with 90-94% [mm], while the polymerization VMA is least stereospecific. Several lines of evidence from both homo- and block copolymerization results have demonstrated living characteristics of the AMA polymerization by 1. Mechanistic studies of this polymerization have yielded a monometallic coordination-addition polymerization mechanism involving the eight-membered chelating intermediate. Post-functionalization of isotactic polymers bearing the pendant vinyl group on every repeating unit via the thiol-ene "click" reaction achieves a full conversion of all the pendant double bonds to the corresponding thioether bonds. Photocuring of such isotactic polymers is also successful, producing an elastic material readily characterizable by dynamic mechanical analysis.
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Affiliation(s)
- Fernando Vidal
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Ravikumar R Gowda
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Eugene Y-X Chen
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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Buchowicz W, Conder J, Hryciuk D, Zachara J. Nickel-mediated polymerization of methyl methacrylate. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.molcata.2013.09.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sakata K, Fujimoto H. Quantum Chemical Study of B(C6F5)3-Catalyzed Hydrosilylation of Carbonyl Group. J Org Chem 2013; 78:12505-12. [DOI: 10.1021/jo402195x] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Ken Sakata
- Faculty
of Pharmaceutical Sciences, Hoshi University, Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - Hiroshi Fujimoto
- Department
of Molecular Engineering, Graduate School
of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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Cabeza JA, Damonte M, García-Álvarez P, Pérez-Carreño E. Easy abstraction of a hydride anion from an alkyl C–H bond of a coordinated bis(N-heterocyclic carbene). Chem Commun (Camb) 2013; 49:2813-5. [DOI: 10.1039/c3cc40619a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Main-group classical and frustrated Lewis pairs (CLPs and FLPs) comprising strong Lewis acids (LAs) and strong Lewis bases (LBs) are highly active for polymerization of conjugated polar alkenes, affording typically high molecular weight polymers with relatively narrow molecular weight distributions. Especially effective systems are the Lewis pairs (LPs) consisting of the strong LA Al(C6F5)3 and strong LBs, such as achiral phosphines and chiral chelating diphosphines, N-heterocyclic carbenes, and phosphazene superbases, for polymerization of methacrylates and acrylamides as well as renewable α-methylene-γ-butyrolactones. Chain initiation involves cooperative addition of LPs to the monomer to generate zwitterionic active species, and chain propagation proceeds via a bimetallic, activated-monomer addition mechanism. Transition metal nucleophile/electrophile pairs comprising neutral metallocene bis(ester enolate)s and strong LAs E(C6F5)3 (E = Al, B) generate two drastically different polymerization systems, depending on the LA. With E = Al, catalyst activation and chain initiating events lead to dually active ion-pairs, thereby effecting ion-pairing polymerization that affords polymers with unique stereo-multiblock microstructures. With E = B, on the other hand, the FLP-induced catalyst activation generates metallacyclic cations paired with the hydridoborate anion [HB(C6F5)3](-); uniquely, such ion-pairs effect catalytic polymerization of conjugated polar alkenes by an H-shuttling mechanism, with the cation catalyzing chain growth and the anion promoting chain transfer by shuttling the hydride between the cation and anion centers through the neutral borane.
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Affiliation(s)
- Eugene Y-X Chen
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523-1872, USA,
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Miyake GM, Chen EYX. Synthesis of highly syndiotactic polymers by discrete catalysts or initiators. Polym Chem 2011. [DOI: 10.1039/c1py00245g] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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