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Tashiro K, Akiyama M, Kashiwagi K, Okazoe T. The Fluorocarbene Exploit: Enforcing Alternation in Ring-Opening Metathesis Polymerization. J Am Chem Soc 2023; 145:2941-2950. [PMID: 36701256 DOI: 10.1021/jacs.2c11373] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fluoroalkenes are known to be notoriously reluctant substrates for olefin metathesis due to the generation of thermodynamically stable Fischer-type fluorocarbene intermediates, which invariably fail to undergo further reaction. In the present disclosure, we find that fluorine substitution on the sp2 carbon also strictly suppresses homopolymerization of norbornene derivatives (NBEs), and this can be harnessed to achieve alternating ring-opening metathesis polymerization (ROMP) with an appropriately electron-rich comonomer. Dihydrofuran (DHF) is thereby shown to undergo alternating ROMP with fluorinated norbornenes, the perfectly alternating structure of the resulting copolymer having been unambiguously elucidated by 1H, 19F, and 13C NMR analyses. Furthermore, we find that the degradability of the resultant copolymers in acidic media via hydrolysis of enol ether moieties in the backbone can be predictably modulated by the number of fluorine atoms present in the NBE comonomer, affording an opportunity to engage with the desirable physical properties of fluorinated polymers while limiting their attendant environmental degradability issues.
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Affiliation(s)
- Kaoru Tashiro
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Midori Akiyama
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kimiaki Kashiwagi
- AGC Inc., Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Takashi Okazoe
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.,AGC Inc., Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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2
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Mechanical reinforcement of isoprene rubbers via metal-coordinated crosslink of carboxyl-terminated telechelic polymers. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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3
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Pal S, Mandal I, Kilbinger AFM. Controlled Alternating Metathesis Copolymerization of Terminal Alkynes. ACS Macro Lett 2022; 11:847-853. [PMID: 35736023 DOI: 10.1021/acsmacrolett.2c00258] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Terminal alkynes display high reactivity toward Ru-carbene metathesis catalysts. However, the formation of a less reactive bulky carbene hinders their homopolymerization. Simultaneously, the higher reactivity of alkynes does not allow efficient cross propagation with sterically less-hindered cycloalkene monomers, resulting in inefficient copolymerization. Nonetheless, terminal alkynes undergo rapid cross-metathesis with vinyl ethers. Therefore, an efficient cross propagation can be achieved with terminal alkynes and cyclic enol ether monomers. Here, we show that terminal alkyne derivatives can be copolymerized in an alternating fashion with 2,3-dihydrofuran using Grubbs' third generation catalyst (G3). A linear relationship of the number-average molecular weight versus monomer to initiator ratio and block copolymer synthesis confirmed a controlled copolymerization. The SEC and NMR analyses of the synthesized copolymers confirmed the excellent control over molecular weight and exclusive alternating nature of the copolymer. The regioselective chain transfer of G3 to vinyl ether and the high reactivity of the Fischer-type Ru carbene toward terminal alkynes was also exploited for polymer conjugation. Finally, the presence of an acid labile backbone functionality in the synthesized alternating copolymers allowed complete degradation of the copolymer within a short time interval which was confirmed by SEC analyses.
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Affiliation(s)
- Subhajit Pal
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
| | - Indradip Mandal
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
| | - Andreas F M Kilbinger
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
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4
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Sui X, Gutekunst WR. Cascade Alternating Metathesis Cyclopolymerization of Diynes and Dihydrofuran. ACS Macro Lett 2022; 11:630-635. [PMID: 35570817 DOI: 10.1021/acsmacrolett.2c00140] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ruthenium alkoxymethylidene complexes have recently come into view as competent species for metathesis copolymerization reactions when coupled with appropriate comonomer targets. Here, we explore the ability of Fischer-type carbenes to participate in cascade alternating metathesis cyclopolymerization (CAMC) through facile terminal alkyne addition. The combination of diyne monomers and an equal feed ratio of low-strain dihydrofuran leads to a controlled chain-growth copolymerization with high degrees of alternation (>97% alternating diads) and produces degradable polymer materials with low dispersities and targetable molecular weights. When combined with enyne monomers, this method is amenable to the synthesis of alternating diblock copolymers that can be fully degraded to short oligomer fragments under aqueous acidic conditions. This work furthers the potential for the generation of functional metathesis materials via Fischer-type ruthenium alkylidenes.
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Affiliation(s)
- Xuelin Sui
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Will R. Gutekunst
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
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5
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Dong Z, Liu P, Crochet A, Kilbinger AFM. Fast Ring-Opening Metathesis Polymerization of Tricyclic Oxanorbornene Derivatives. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhenghao Dong
- Department of Chemistry, University of Fribourg, Chemin du Museé 9, CH-1700 Fribourg, Switzerland
| | - Peng Liu
- Department of Chemistry, University of Fribourg, Chemin du Museé 9, CH-1700 Fribourg, Switzerland
| | - Aurelien Crochet
- Department of Chemistry, University of Fribourg, Chemin du Museé 9, CH-1700 Fribourg, Switzerland
| | - Andreas F. M. Kilbinger
- Department of Chemistry, University of Fribourg, Chemin du Museé 9, CH-1700 Fribourg, Switzerland
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6
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Ji M, Zheng S, Zou C, Chen M. Ruthenium-Catalyzed Diazoacetates/Cyclooctene Metathesis Copolymerization. Polym Chem 2022. [DOI: 10.1039/d2py00886f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As a powerful synthetic tool, ruthenium-catalyzed ring-opening metathesis polymerization (ROMP) has been widely utilized to prepare diverse polymers. In this contribution, we demonstrated the polymerization of cyclooctene in the presence...
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7
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Youn G, Sampson NS. Substituent Effects Provide Access to Tetrasubstituted Ring-Opening Olefin Metathesis of Bicyclo[4.2.0]oct-6-enes. ACS ORGANIC & INORGANIC AU 2021; 1:29-36. [PMID: 34693402 PMCID: PMC8529632 DOI: 10.1021/acsorginorgau.1c00016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 01/20/2023]
Abstract
Herein, we report the origin of unexpected reactivity of bicyclo[4.2.0]oct-6-ene substrates containing an α,β-unsaturated amide moiety in ruthenium-catalyzed alternating ring-opening metathesis polymerization reactions. Specifically, compared with control substrates bearing an ester, alkyl ketone, nitrile, or tertiary amide substituent, α,β-unsaturated substrates with a weakly acidic proton showed increased rates of ring-opening metathesis mediated by Grubbs-type ruthenium catalysts. 1H NMR and IR spectral analyses indicated that deprotonation of the α,β-unsaturated amide substrates resulted in stronger coordination of the carbonyl group to the ruthenium metal center. Principal component analysis identified ring strain and the electron density on the carbonyl oxygen (based on structures optimized by means of ωB97X-D/6311+G(2df,2p) calculations) as the two key contributors to fast ring-opening metathesis of the bicyclo[4.2.0]oct-6-enes; whereas the dipole moment, conjugation, and energy of the highest occupied molecular orbital had little to no effect on the reaction rate. We conclude that alternating ring-opening metathesis polymerization reactions of bicyclo[4.2.0]oct-6-enes with unstrained cycloalkenes require an ionizable proton for efficient generation of alternating polymers.
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Pal S, Alizadeh M, Kong P, Kilbinger AFM. Oxanorbornenes: promising new single addition monomers for the metathesis polymerization. Chem Sci 2021; 12:6705-6711. [PMID: 34040745 PMCID: PMC8133030 DOI: 10.1039/d1sc00036e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/31/2021] [Indexed: 12/22/2022] Open
Abstract
Higher ring-opening metathesis propagation rates of exo-norbornene derivatives over endo derivatives are well established in the literature. Here, we report for the first time that endo-isomers of oxanorbornene derivatives show higher reactivity towards ring-opening metathesis with Grubbs' 3rd generation catalyst (G3) than the corresponding exo-isomers. A very high selectivity for the reaction of G3 with endo over the exo-isomers could be shown. Furthermore, single molecular addition of the endo-isomers with G3 was observed. On the other hand, pure exo-monomers could successfully be homopolymerized. Mixtures of exo- and endo- monomers, however, prevented the homopolymerization of the exo-monomer. Such mixtures could successfully be copolymerized with cycloalkenes, resulting in alternating copolymers. An oxanorbornadiene derivative could be shown to undergo single addition reactions, exploited in the preparation of mono-end functional ROMP polymers. These could be selectively derivatized via endgroup selective thiol-ene click reactions. A thiol and alcohol end functional ROMP polymer was synthesized, and the efficient end functionalization was confirmed by 1H NMR spectroscopy and MALDI-ToF spectrometry.
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Affiliation(s)
- Subhajit Pal
- Department of Chemistry, University of Fribourg Chemin du Musée 9 1700 Fribourg Switzerland
| | - Mahshid Alizadeh
- Department of Chemistry, University of Fribourg Chemin du Musée 9 1700 Fribourg Switzerland
| | - Phally Kong
- Department of Chemistry, University of Fribourg Chemin du Musée 9 1700 Fribourg Switzerland
| | - Andreas F M Kilbinger
- Department of Chemistry, University of Fribourg Chemin du Musée 9 1700 Fribourg Switzerland
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Wang X, Dai L, Jie S, Bu Z, Li B. Telechelic Carboxyl‐Terminated Polynorbornenes and Copolym‐ers via Chain‐Transfer Ring‐Opening Metathesis Polymerization. ChemistrySelect 2020. [DOI: 10.1002/slct.202002441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xixi Wang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 China
| | - Lu Dai
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 China
| | - Suyun Jie
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 China
| | - Zhiyang Bu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 China
| | - Bo‐Geng Li
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 China
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10
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Sui X, Zhang T, Pabarue AB, Fu L, Gutekunst WR. Alternating Cascade Metathesis Polymerization of Enynes and Cyclic Enol Ethers with Active Ruthenium Fischer Carbenes. J Am Chem Soc 2020; 142:12942-12947. [PMID: 32662989 PMCID: PMC7466819 DOI: 10.1021/jacs.0c06045] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Ruthenium alkoxymethylidene complexes have rarely been demonstrated as active species in metathesis reactions and are frequently regarded as inert. Herein, we highlight the ability of these Fischer-type carbenes to participate in cascade alternating ring-opening metathesis polymerization through their efficient alkyne addition reactions. When enyne monomers are combined with low-strain cyclic vinyl ethers, a controlled chain-growth copolymerization occurs that exhibits high degrees of alternation (>90% alternating diads) and produces degradable poly(vinyl ether) materials with low dispersities and targetable molecular weights. This new method is amenable to the synthesis of alternating diblock polymers that can be degraded to small-molecule fragments under aqueous acidic conditions. This work furthers the potential of Fischer-type ruthenium alkylidenes in polymerization strategies and presents new avenues for the generation of functional metathesis materials.
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Affiliation(s)
- Xuelin Sui
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Tianqi Zhang
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Alec B Pabarue
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Liangbing Fu
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Will R Gutekunst
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
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