1
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O'Neill RT, Boulatov R. Mechanochemical Approaches to Fundamental Studies in Soft-Matter Physics. Angew Chem Int Ed Engl 2024; 63:e202402442. [PMID: 38404161 DOI: 10.1002/anie.202402442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/24/2024] [Accepted: 02/25/2024] [Indexed: 02/27/2024]
Abstract
Stretching a segment of a polymer beyond its contour length makes its (primarily backbone) bonds more dissociatively labile, which enables polymer mechanochemistry. Integrating some backbone bonds into suitably designed molecular moieties yields mechanistically and kinetically diverse chemistry, which is becoming increasingly exploitable. Examples include, most prominently, attempts to improve mechanical properties of bulk polymers, as well as prospective applications in drug delivery and synthesis. This review aims to highlight an emerging effort to apply the concepts and experimental tools of mechanochemistry to fundamental physical questions in soft matter. A succinct summary of the state-of-the-knowledge of the field, with emphasis on foundational concepts and generalizable observations, is followed by analysis of 3 recent examples of mechanochemistry yielding molecular-level details of elastomer failure, macromolecular chain dynamics in elongational flows and kinetic allostery. We conclude with reasons to assume that the highlighted approaches are generalizable to a broader range of physical problems than considered to date.
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Affiliation(s)
- Robert T O'Neill
- Department of Chemistry, University of Liverpool, University of Liverpool, Department of Chemistry, Grove Street, Liverpool, L69 7ZD
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, University of Liverpool, Department of Chemistry, Grove Street, Liverpool, L69 7ZD
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2
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Shao BR, Ren BH, Jiang WF, Shi L. Synthesis of Helical-Shaped Axially Chiral Bisoxime Ethers via Chiral Phosphoric-Acid-Catalyzed Sequential Enantioselective Condensations. Org Lett 2024; 26:2646-2650. [PMID: 38530907 DOI: 10.1021/acs.orglett.4c00722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
A successful synthesis of helical-shaped axially chiral bisoxime ethers is reported. This approach utilized symmetric L-shaped diketone scaffolds as carbonyl components for the enantioselective condensation with hydroxylamines, delivering dual axially chiral oxime ethers with up to 99% ee. Additionally, the axially chiral mono-oxime ethers of azabicyclic ketones with high ee's were also successfully produced. Various chiral bicyclic lactams can be readily synthesized via Beckmann rearrangement, demonstrating a potential application in organic synthetic chemistry.
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Affiliation(s)
- Bing-Ru Shao
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Bai-Hao Ren
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Wen-Feng Jiang
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
| | - Lei Shi
- School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
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3
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Zhang H, Zoubi AZ, Silberstein MN, Diesendruck CE. Mechanochemistry in Block Copolymers: New Scission Site due to Dynamic Phase Separation. Angew Chem Int Ed Engl 2023; 62:e202314781. [PMID: 37962518 DOI: 10.1002/anie.202314781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/15/2023]
Abstract
Mechanochemistry can lead to the degradation of the properties of covalent macromolecules. In recent years, numerous functional materials have been developed based on block copolymers (BCPs), however, like homopolymers, their chains could undergo mechanochemical damage during processing, which could have crucial impact on their performance. To investigate the mechanochemical response of BCPs, multiple polymers comprising different ratios of butyl acrylate and methyl methacrylate were prepared with similar degree of polymerization and stressed in solution via ultrasonication. Interestingly, all BCPs, regardless of the amount of the methacrylate monomer, presented a mechanochemistry rate constant similar to that of the methacrylate homopolymer, while a random copolymer reacted like the acrylate homopolymer. Size-exclusion chromatography showed that, in addition to the typical main peak shift towards higher retention times, a different daughter fragment was produced indicating a secondary selective scission site, situated around the covalent connection between the two blocks. Molecular dynamics modeling using acrylate and methacrylate oligomers were carried out and indicated that dynamic phase separation occurs even in a good solvent. Such non-random conformations can explain the faster polymer mechanochemistry. Moreover, the dynamic model for end-to-end chain overstretching supports bond scission which is not necessarily chain-centered.
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Affiliation(s)
- Hang Zhang
- Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Haifa, 3200008, Israel
| | - Alan Z Zoubi
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Meredith N Silberstein
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Charles E Diesendruck
- Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Haifa, 3200008, Israel
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4
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Imato K, Ishii A, Kaneda N, Hidaka T, Sasaki A, Imae I, Ooyama Y. Thermally Stable Photomechanical Molecular Hinge: Sterically Hindered Stiff-Stilbene Photoswitch Mechanically Isomerizes. JACS AU 2023; 3:2458-2466. [PMID: 37772185 PMCID: PMC10523368 DOI: 10.1021/jacsau.3c00213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 09/30/2023]
Abstract
Molecular photoswitches are extensively used as molecular machines because of the small structures, simple motions, and advantages of light including high spatiotemporal resolution. Applications of photoswitches depend on the mechanical responses, in other words, whether they can generate motions against mechanical forces as actuators or can be activated and controlled by mechanical forces as mechanophores. Sterically hindered stiff stilbene (HSS) is a promising photoswitch offering large hinge-like motions in the E/Z isomerization, high thermal stability of the Z isomer, which is relatively unstable compared to the E isomer, with a half-life of ca. 1000 years at room temperature, and near-quantitative two-way photoisomerization. However, its mechanical response is entirely unexplored. Here, we elucidate the mechanochemical reactivity of HSS by incorporating one Z or E isomer into the center of polymer chains, ultrasonicating the polymer solutions, and stretching the polymer films to apply elongational forces to the embedded HSS. The present study demonstrated that HSS mechanically isomerizes only in the Z to E direction and reversibly isomerizes in combination with UV light, i.e., works as a photomechanical hinge. The photomechanically inducible but thermally irreversible hinge-like motions render HSS unique and promise unconventional applications differently from existing photoswitches, mechanophores, and hinges.
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Affiliation(s)
- Keiichi Imato
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Akira Ishii
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Naoki Kaneda
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Taichi Hidaka
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Ayane Sasaki
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Ichiro Imae
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Yousuke Ooyama
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
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5
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Noh J, Koo MB, Jung J, Peterson GI, Kim KT, Choi TL. Monodisperse Cyclic Polymer Mechanochemistry: Scission Kinetics and the Dynamic Memory Effect with Ultrasonication and Ball-Mill Grinding. J Am Chem Soc 2023; 145:18432-18438. [PMID: 37486970 DOI: 10.1021/jacs.3c04733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
A series of monodisperse cyclic and linear poly(d,l-lactide)s (c-PLA and l-PLA, respectively) were prepared with various degrees of polymerization (DP) using an iterative convergent synthesis approach. The absence of a molecular weight distribution provided us a chance to study their mechanochemical reactivity without obstructions arising from the size distribution. Additionally, we prepared l- and c-PLAs with identical DPs, which enabled us to attribute differences in scission rates to the cyclic polymer architecture alone. The polymers were subjected to ultrasonication (US) and ball-mill grinding (BMG), and their degradation kinetics were explored. Up to 9.0 times larger scission rates were observed for l-PLA (compared to c-PLA) with US, but the difference was less than 1.9 times with BMG. Fragmentation requires two backbone scission events for c-PLA, and we were able to observe linear intermediates (formed after a single scission) for the first time. We also developed a new method of studying the dynamic memory effect in US by characterizing and comparing the daughter fragment molecular weight distributions of l- and c-PLAs. These results provide new insights into the influence of the cyclic polymer architecture on mechanochemical reactions as well as differences in reactivity observed with US and BMG.
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Affiliation(s)
- Jinkyung Noh
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Mo Beom Koo
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Jisoo Jung
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Gregory I Peterson
- Department of Chemistry and Research Institute of Basic Science, Incheon National University, Incheon 22012, Republic of Korea
| | - Kyoung Taek Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Tae-Lim Choi
- Department of Materials, ETH Zürich, Zürich 8093, Switzerland
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Zhang H, Diesendruck CE. Off-center Mechanophore Activation in Block Copolymers. Angew Chem Int Ed Engl 2023; 62:e202213980. [PMID: 36394518 PMCID: PMC10108114 DOI: 10.1002/anie.202213980] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Indexed: 11/18/2022]
Abstract
Block copolymers (BCPs) are used in numerous applications in modern materials science. Yet, like homopolymers, BCPs can undergo covalent bond scission when mechanically stressed (mechanochemistry), which could lead to unexpected consequences in such applications. BCPs' heterogeneity may affect force transduction, perhaps changing force distribution and localization. To verify this, a gem-dichlorocyclopropane (gDCC) embedded linear chain is prepared and extended with a poly(methyl methacrylate) block. When stressed in solution, the mechanochemical ring-opening of gDCC is accelerated compared to homopolymers, even though the mechanophores are at the chain ends. Moreover, a higher mechanophore activation selectivity is obtained. These results indicate that mechanochemical response outside, and even far from the chain center is quite prominent in BCPs, and that forces along the polymer chain can efficiently activate multi-mechanophores regions, even when far from the polymer midchain.
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Affiliation(s)
- Hang Zhang
- Schulich Faculty of Chemistry, Technion-, Israel Institute of Technology, Haifa, 3200008, Israel
| | - Charles E Diesendruck
- Schulich Faculty of Chemistry, Technion-, Israel Institute of Technology, Haifa, 3200008, Israel
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7
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Zhou J, Sathe D, Ciccotelli A, Wang J. Synthesis and mechanochemical inertness of a Zn (
II
) bidipyrrin double helix. JOURNAL OF POLYMER SCIENCE 2022. [DOI: 10.1002/pol.20220579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Junfeng Zhou
- School of Polymer Science and Polymer Engineering The University of Akron Akron Ohio USA
| | - Devavrat Sathe
- School of Polymer Science and Polymer Engineering The University of Akron Akron Ohio USA
| | - Andrew Ciccotelli
- School of Polymer Science and Polymer Engineering The University of Akron Akron Ohio USA
| | - Junpeng Wang
- School of Polymer Science and Polymer Engineering The University of Akron Akron Ohio USA
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