1
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Wang C, Sun CL, Boulatov R. Productive chemistry induced by mechanochemically generated macroradicals. Chem Commun (Camb) 2024. [PMID: 39171460 DOI: 10.1039/d4cc03206c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Large or repeated mechanical loads degrade polymeric materials by accelerating chain fragmentation. This mechanochemical backbone fracture usually occurs by homolysis of otherwise inert C-C, C-O and C-S bonds, generating highly reactive macroradicals. Because backbone fracture is detrimental on its own and the resulting macroradicals can initiate damaging reaction cascades, a major thrust in contemporary polymer mechanochemistry is to suppress it, usually by mechanochemical release of "hidden length" that dissipates local molecular strain. Here we summarize an emerging complementary strategy of channelling mechanochemically generated macroradicals in reaction cascades to form new load-bearing chemical bonds, which enables local self-healing or self-strengthening, and/or to generate mechanofluorescence, which could yield detailed quantitative molecular understanding of how material-failure-inducing macroscopic mechanical loads distribute across the network. We aim to identify generalizable lessons derivable from the reported implementations of this strategy and outline the key challenges in adapting it to diverse polymeric materials and loading scenarios.
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Affiliation(s)
- Chenxu Wang
- College of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, Xi'an 710054, China.
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
| | - Cai-Li Sun
- College of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, Xi'an 710054, China.
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
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2
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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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3
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Zheng J, Das B, Sugihara K. Dual Friction Force/Fluorescence Microscopy. Anal Chem 2024; 96:949-956. [PMID: 38180748 DOI: 10.1021/acs.analchem.3c04625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Friction force microscopy (FFM) is a mode of atomic force microscopy (AFM) that quantifies both normal and horizontal forces against substrates. Recent improvement in its accuracy at nanonewton ranges and the possibility of combining AFM with fluorescence microscopy enabled the simultaneous characterization by FFM and fluorescence microscopy. This Tutorial describes the operation principle of the dual friction force/fluorescence microscopy setup and highlights its emerging applications in mechanochromic materials.
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Affiliation(s)
- Jianlu Zheng
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-Ku, Tokyo 153-8505, Japan
| | - Bratati Das
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-Ku, Tokyo 153-8505, Japan
| | - Kaori Sugihara
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-Ku, Tokyo 153-8505, Japan
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4
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de Jong J, Siegler MA, Wezenberg SJ. A Photoswitchable Macrocycle Controls Anion-Templated Pseudorotaxane Formation and Axle Relocalization. Angew Chem Int Ed Engl 2024; 63:e202316628. [PMID: 38059917 DOI: 10.1002/anie.202316628] [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: 11/02/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 12/08/2023]
Abstract
Important biological processes, such as signaling and transport, are regulated by dynamic binding events. The development of artificial supramolecular systems in which binding between different components is controlled could help emulate such processes. Herein, we describe stiff-stilbene-containing macrocycles that can be switched between (Z)- and (E)-isomers by light, as demonstrated by UV/Vis and 1 H NMR spectroscopy. The (Z)-isomers can be effectively threaded by pyridinium halide axles to give pseudorotaxane complexes, as confirmed by 1 H NMR titration studies and single-crystal X-ray crystallography. The overall stability of these complexes can be tuned by varying the templating counteranion. However, upon light-induced isomerization to the (E)-isomer, the threading capability is drastically reduced. The axle component, in addition, can form a heterodimeric complex with a secondary isophthalamide host. Therefore, when all components are combined, light irradiation triggers axle exchange between the macrocycle and this secondary host, which has been monitored by 1 H NMR spectroscopy and simulated computationally.
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Affiliation(s)
- Jorn de Jong
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Sander J Wezenberg
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
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5
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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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6
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O'Neill RT, Boulatov R. Experimental quantitation of molecular conditions responsible for flow-induced polymer mechanochemistry. Nat Chem 2023; 15:1214-1223. [PMID: 37430105 DOI: 10.1038/s41557-023-01266-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 06/05/2023] [Indexed: 07/12/2023]
Abstract
Fragmentation of macromolecular solutes in rapid flows is of considerable fundamental and practical importance. The sequence of molecular events preceding chain fracture is poorly understood, because such events cannot be visualized directly but must be inferred from changes in the bulk composition of the flowing solution. Here we describe how analysis of same-chain competition between fracture of a polystyrene chain and isomerization of a chromophore embedded in its backbone yields detailed characterization of the distribution of molecular geometries of mechanochemically reacting chains in sonicated solutions. In our experiments the overstretched (mechanically loaded) chain segment grew and drifted along the backbone on the same timescale as, and in competition with, the mechanochemical reactions. Consequently, only <30% of the backbone of a fragmenting chain is overstretched, with both the maximum force and the maximum reaction probabilities located away from the chain centre. We argue that quantifying intrachain competition is likely to be mechanistically informative for any flow fast enough to fracture polymer chains.
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Affiliation(s)
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Liverpool, UK.
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7
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Walter M, Linsler D, König T, Gäbert C, Reinicke S, Moseler M, Mayrhofer L. Mechanochemical Activation of Anthracene [4+4] Cycloadducts. J Phys Chem Lett 2023; 14:1445-1451. [PMID: 36734822 DOI: 10.1021/acs.jpclett.2c03493] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Controlled formation and breaking of weak chemical bonds is a versatile method for modifying the properties of materials. Anthracene [4+4] cycloadducts are a prime example that can be formed by light and opened by external forces. We address the theoretical description of mechanochemistry of these cycloadducts, where the standard constraint geometry simulates forces approach fails due to the lack of consideration of temperature. Explicit inclusion of external forces reveals the corresponding transition barriers that are clearly dominated by rupture of the [4+4] inter-anthracene bonds. Other bonds come into play at extremely large forces only, which cannot be expected to be reached under ambient conditions. The theoretical results are in line with the experimental rheology of [4+4]-linked anthracene polymers, which indicates reversible re-formation of [4+4] cycloaddition bonds with ultraviolet light after mechanochemical bond breaking due to applied shear stress.
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Affiliation(s)
- Michael Walter
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79085Freiburg, Germany
- Cluster of Excellence livMatS@FIT, 79110Freiburg, Germany
| | - Dominic Linsler
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
| | - Tobias König
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
| | | | | | - Michael Moseler
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
- Cluster of Excellence livMatS@FIT, 79110Freiburg, Germany
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8
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Yu Y, Zheng X, Duan C, Craig SL, Widenhoefer RA. Force-Modulated Selectivity of the Rhodium-Catalyzed Hydroformylation of 1-Alkenes. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04534] [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)
- Yichen Yu
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Xujun Zheng
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Chenghao Duan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Stephen L. Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Ross A. Widenhoefer
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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9
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Khodayeki S, Maftuhin W, Walter M. Force Dependent Barriers from Analytic Potentials within Elastic Environments. Chemphyschem 2022; 23:e202200237. [PMID: 35703590 DOI: 10.1002/cphc.202200237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/14/2022] [Indexed: 01/07/2023]
Abstract
Bond rupture under the action of external forces is usually induced by temperature fluctuations, where the key quantity is the force dependent barrier that needs to be overcome. Using analytic potentials we find that these barriers are fully determined by the dissociation energy and the maximal force the potential can withstand. The barrier shows a simple dependence on these two quantities that allows for a re-interpretation of the Eyring-Zhurkov-Bell length Δ x ‡ and the expressions in theories going beyond that. It is shown that solely elastic environments do not change this barrier in contrast to the predictions of constraint geometry simulate external force (COGEF) strategies. The findings are confirmed by explicit calculations of bond rupture in a polydimethylsiloxane model.
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Affiliation(s)
- Samaneh Khodayeki
- Freiburger Institut für Interaktive Materialien und Bioinspirierte Technologien, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
- Physikalisches Institut, Universität Freiburg, Herrmann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Wafa Maftuhin
- Freiburger Institut für Interaktive Materialien und Bioinspirierte Technologien, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
- Physikalisches Institut, Universität Freiburg, Herrmann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Michael Walter
- Freiburger Institut für Interaktive Materialien und Bioinspirierte Technologien, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
- Physikalisches Institut, Universität Freiburg, Herrmann-Herder-Straße 3, 79104, Freiburg, Germany
- Cluster of Excellence livMatS@FIT, Freiburg, Germany
- Fraunhofer Institut für Werkstoffmechanik, Wöhlerstraße 11, 79108, Freiburg, Germany
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10
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Wang C, Akbulatov S, Chen Q, Tian Y, Sun CL, Couty M, Boulatov R. The molecular mechanism of constructive remodeling of a mechanically-loaded polymer. Nat Commun 2022; 13:3154. [PMID: 35672410 PMCID: PMC9174275 DOI: 10.1038/s41467-022-30947-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 05/25/2022] [Indexed: 02/03/2023] Open
Abstract
Large or repeated mechanical loads usually degrade polymers by accelerating fragmentation of their backbones but rarely, they can cause new backbone bonds to form. When these new bonds form faster than the original bonds break, mechanical degradation may be arrested or reversed in real time. Exploiting such constructive remodeling has proven challenging because we lack an understanding of the competition between bond-forming and bond-breaking reactions in mechanically-stressed polymers. Here we report the molecular mechanism and analysis of constructive remodeling driven by the macroradical products of mechanochemical fragmentation of a hydrocarbon backbone. By studying the changing compositions of a random copolymer of styrene and butadiene sheared at 10 °C in the presence of different additives we developed an approach to characterizing this growth/fracture competition, which is generalizable to other underlying chemistries. Our results demonstrate that constructive remodeling is achievable under practically relevant conditions, requires neither complex chemistries, elaborate macromolecular architectures or free monomers, and is amenable to detailed mechanistic interrogation and simulation. These findings constitute a quantitative framework for systematic studies of polymers capable of autonomously counteracting mechanical degradation at the molecular level.
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Affiliation(s)
- Chenxu Wang
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Sergey Akbulatov
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Qihan Chen
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Yancong Tian
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Cai-Li Sun
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Marc Couty
- Manufacture Française des Pneumatiques Michelin, Clermont-Ferrand, 63000, France.
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK.
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11
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O’Neill RT, Boulatov R. The Contributions of Model Studies for Fundamental Understanding of Polymer Mechanochemistry. Synlett 2021. [DOI: 10.1055/a-1710-5656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
AbstractThe exciting field of polymer mechanochemistry has made great empirical progress in discovering reactions in which a stretching force accelerates scission of strained bonds using single molecule force spectroscopy and ultrasonication experiments. Understanding why these reactions happen, i.e., the fundamental physical processes that govern coupling of macroscopic motion to chemical reactions, as well as discovering other patterns of mechanochemical reactivity require complementary techniques, which permit a much more detailed characterization of reaction mechanisms and the distribution of force in reacting molecules than are achievable in SMFS or ultrasonication. A molecular force probe allows the specific pattern of molecular strain that is responsible for localized reactions in stretched polymers to be reproduced accurately in non-polymeric substrates using molecular design rather than atomistically intractable collective motions of millions of atoms comprising macroscopic motion. In this review, we highlight the necessary features of a useful molecular force probe and describe their realization in stiff stilbene macrocycles. We describe how studying these macrocycles using classical tools of physical organic chemistry has allowed detailed characterizations of mechanochemical reactivity, explain some of the most unexpected insights enabled by these probes, and speculate how they may guide the next stage of mechanochemistry.
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Affiliation(s)
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University
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12
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Volarić J, Szymanski W, Simeth NA, Feringa BL. Molecular photoswitches in aqueous environments. Chem Soc Rev 2021; 50:12377-12449. [PMID: 34590636 PMCID: PMC8591629 DOI: 10.1039/d0cs00547a] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Indexed: 12/17/2022]
Abstract
Molecular photoswitches enable dynamic control of processes with high spatiotemporal precision, using light as external stimulus, and hence are ideal tools for different research areas spanning from chemical biology to smart materials. Photoswitches are typically organic molecules that feature extended aromatic systems to make them responsive to (visible) light. However, this renders them inherently lipophilic, while water-solubility is of crucial importance to apply photoswitchable organic molecules in biological systems, like in the rapidly emerging field of photopharmacology. Several strategies for solubilizing organic molecules in water are known, but there are not yet clear rules for applying them to photoswitchable molecules. Importantly, rendering photoswitches water-soluble has a serious impact on both their photophysical and biological properties, which must be taken into consideration when designing new systems. Altogether, these aspects pose considerable challenges for successfully applying molecular photoswitches in aqueous systems, and in particular in biologically relevant media. In this review, we focus on fully water-soluble photoswitches, such as those used in biological environments, in both in vitro and in vivo studies. We discuss the design principles and prospects for water-soluble photoswitches to inspire and enable their future applications.
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Affiliation(s)
- Jana Volarić
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | - Wiktor Szymanski
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
- Department of Radiology, Medical Imaging Center, University of Groningen, University Medical Centre Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Nadja A Simeth
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
| | - Ben L Feringa
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
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13
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Yu Y, Wang C, Wang L, Sun CL, Boulatov R, Widenhoefer RA, Craig SL. Force-modulated reductive elimination from platinum(ii) diaryl complexes. Chem Sci 2021; 12:11130-11137. [PMID: 34522310 PMCID: PMC8386663 DOI: 10.1039/d1sc03182a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/19/2021] [Indexed: 11/21/2022] Open
Abstract
Coupled mechanical forces are known to drive a range of covalent chemical reactions, but the effect of mechanical force applied to a spectator ligand on transition metal reactivity is relatively unexplored. Here we quantify the rate of C(sp2)-C(sp2) reductive elimination from platinum(ii) diaryl complexes containing macrocyclic bis(phosphine) ligands as a function of mechanical force applied to these ligands. DFT computations reveal complex dependence of mechanochemical kinetics on the structure of the force-transducing ligand. We validated experimentally the computational finding for the most sensitive of the ligand designs, based on MeOBiphep, by coupling it to a macrocyclic force probe ligand. Consistent with the computations, compressive forces decreased the rate of reductive elimination whereas extension forces increased the rate relative to the strain-free MeOBiphep complex with a 3.4-fold change in rate over a ∼290 pN range of restoring forces. The calculated natural bite angle of the free macrocyclic ligand changes with force, but 31P NMR analysis and calculations strongly suggest no significant force-induced perturbation of ground state geometry within the first coordination sphere of the (P-P)PtAr2 complexes. Rather, the force/rate behavior observed across this range of forces is attributed to the coupling of force to the elongation of the O⋯O distance in the transition state for reductive elimination. The results suggest opportunities to experimentally map geometry changes associated with reactions in transition metal complexes and potential strategies for force-modulated catalysis.
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Affiliation(s)
- Yichen Yu
- Department of Chemistry, Duke University Durham North Carolina 27708 USA
| | - Chenxu Wang
- Department of Chemistry, University of Liverpool Crown Street Liverpool L69 7ZD UK
| | - Liqi Wang
- Department of Chemistry, Duke University Durham North Carolina 27708 USA
| | - Cai-Li Sun
- Department of Chemistry, University of Liverpool Crown Street Liverpool L69 7ZD UK
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool Crown Street Liverpool L69 7ZD UK
| | - Ross A Widenhoefer
- Department of Chemistry, Duke University Durham North Carolina 27708 USA
| | - Stephen L Craig
- Department of Chemistry, Duke University Durham North Carolina 27708 USA
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14
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O’Neill RT, Boulatov R. The many flavours of mechanochemistry and its plausible conceptual underpinnings. Nat Rev Chem 2021; 5:148-167. [PMID: 37117533 DOI: 10.1038/s41570-020-00249-y] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2020] [Indexed: 12/12/2022]
Abstract
Mechanochemistry describes diverse phenomena in which mechanical load affects chemical reactivity. The fuzziness of this definition means that it includes processes as seemingly disparate as motor protein function, organic synthesis in a ball mill, reactions at a propagating crack, chemical actuation, and polymer fragmentation in fast solvent flows and in mastication. In chemistry, the rate of a reaction in a flask does not depend on how fast the flask moves in space. In mechanochemistry, the rate at which a material is deformed affects which and how many bonds break. In other words, in some manifestations of mechanochemistry, macroscopic motion powers otherwise endergonic reactions. In others, spontaneous chemical reactions drive mechanical motion. Neither requires thermal or electrostatic gradients. Distinct manifestations of mechanochemistry are conventionally treated as being conceptually independent, which slows the field in its transformation from being a collection of observations to a rigorous discipline. In this Review, we highlight observations suggesting that the unifying feature of mechanochemical phenomena may be the coupling between inertial motion at the microscale to macroscale and changes in chemical bonding enabled by transient build-up and relaxation of strains, from macroscopic to molecular. This dynamic coupling across multiple length scales and timescales also greatly complicates the conceptual understanding of mechanochemistry.
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15
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Villarón D, Siegler MA, Wezenberg SJ. A photoswitchable strapped calix[4]pyrrole receptor: highly effective chloride binding and release. Chem Sci 2021; 12:3188-3193. [PMID: 34164086 PMCID: PMC8179391 DOI: 10.1039/d0sc06686a] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/12/2021] [Indexed: 12/12/2022] Open
Abstract
A stiff-stilbene strapped calix[4]pyrrole receptor can be reversibly switched by light between a strong chloride-binding Z-isomer and a very weakly binding E-isomer. The light-induced switching process is monitored by UV-Vis and 1H NMR spectroscopy and chloride binding is studied in detail using both 1H NMR and ITC titrations in DMSO and MeCN. In DMSO, at millimolar concentrations, switching from a fully bound to an almost fully unbound state can be triggered. Quantification of the binding constants in MeCN reveals an extraordinary 8000-fold affinity difference between the Z- and E-isomer. Single crystal X-ray crystallographic analysis gives insight into the structure of the photogenerated E-isomer and the geometry of the chloride-bound receptors is optimized by DFT calculations. The highly effective control of binding affinity demonstrated in this work opens up new prospects for on demand binding and release in extractions and photocontrol of membrane transport processes, among other applications.
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Affiliation(s)
- David Villarón
- Leiden Institute of Chemistry, Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
| | - Sander J Wezenberg
- Leiden Institute of Chemistry, Leiden University Einsteinweg 55 2333 CC Leiden The Netherlands
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16
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Krishnan BP, Xue L, Xiong X, Cui J. Photoinduced Strain-Assisted Synthesis of a Stiff-Stilbene Polymer by Ring-Opening Metathesis Polymerization. Chemistry 2020; 26:14828-14832. [PMID: 32533881 PMCID: PMC7756494 DOI: 10.1002/chem.202002418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Indexed: 01/13/2023]
Abstract
Developing a novel strategy to synthesize photoresponsive polymers is of significance owing to their potential applications. We report a photoinduced strain-assisted synthesis of main-chain stiff-stilbene polymers by using ring-opening metathesis polymerization (ROMP), activating a macrocyclic π-bond connected to a stiff-stilbene photoswitch through a linker. Since the linker acts as an external constraint, the photoisomerization to the E-form leads to the stiff-stilbene being strained and thus reactive to ROMP. The photoisomerization of Z-form to E-form was investigated using time-dependent NMR studies and UV/Vis spectroscopy. The DFT calculation showed that the E-form was less stable due to a lack of planarity. By the internal strain developed due to the linker constraint through photoisomerization, the E-form underwent ROMP by a second generation Grubbs catalyst. In contrast, Z-form did not undergo polymerization under similar conditions. The MALDI-TOF spectrum of E-form after polymerization showed the presence of oligomers of >5.2 kDa.
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Affiliation(s)
- Baiju P. Krishnan
- INM-Leibniz Institute for New MaterialsCampus D2 2Saarbrücken66123Germany
| | - Lulu Xue
- INM-Leibniz Institute for New MaterialsCampus D2 2Saarbrücken66123Germany
| | - Xinhong Xiong
- INM-Leibniz Institute for New MaterialsCampus D2 2Saarbrücken66123Germany
| | - Jiaxi Cui
- INM-Leibniz Institute for New MaterialsCampus D2 2Saarbrücken66123Germany
- Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengduSichuanChina
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17
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Tian Y, Cao X, Li X, Zhang H, Sun CL, Xu Y, Weng W, Zhang W, Boulatov R. A Polymer with Mechanochemically Active Hidden Length. J Am Chem Soc 2020; 142:18687-18697. [PMID: 33064473 PMCID: PMC7596784 DOI: 10.1021/jacs.0c09220] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Incorporating hidden length into polymer chains can improve their mechanical properties, because release of the hidden length under mechanical loads enables localized strain relief without chain fracture. To date, the design of hidden length has focused primarily on the choice of the sacrificial bonds holding the hidden length together. Here we demonstrate the advantages of adding mechanochemical reactivity to hidden length itself, using a new mechanophore that integrates (Z)-2,3-diphenylcyclobutene-1,4-dicarboxylate, with hitherto unknown mechanochemistry, into macrocyclic cinnamate dimers. Stretching a polymer of this mechanophore more than doubles the chain contour length without fracture. DFT calculations indicate that the sequential dissociation of the dimer, followed by cyclobutene isomerization at higher forces yields a chain fracture energy 11 times that of a simple polyester of the same initial contour length and preserves high energy-dissipating capacity up to ∼3 nN. In sonicated solutions cyclobutene isomerizes to two distinct products by competing reaction paths, validating the computed mechanochemical mechanism and suggesting an experimental approach to quantifying the distribution of single-chain forces under diverse loading scenarios.
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Affiliation(s)
- Yancong Tian
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Xiaodong Cao
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China
| | - Xun Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012, People's Republic of China
| | - Huan Zhang
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China
| | - Cai-Li Sun
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Yuanze Xu
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China
| | - Wengui Weng
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China
| | - Wenke Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012, People's Republic of China
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
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18
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Wang L, Yu Y, Razgoniaev AO, Johnson PN, Wang C, Tian Y, Boulatov R, Craig SL, Widenhoefer RA. Mechanochemical Regulation of Oxidative Addition to a Palladium(0) Bisphosphine Complex. J Am Chem Soc 2020; 142:17714-17720. [PMID: 32957791 DOI: 10.1021/jacs.0c08506] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Here, we report the effect of force applied to the biaryl backbone of a bisphosphine ligand on the rate of oxidative addition of bromobenzene to a ligand-coordinated palladium center. Local compressive and tensile forces on the order of 100 pN were generated using a stiff stilbene force probe. A compressive force increases the rate of oxidative addition, whereas a tensile force decreases the rate, relative to that of the parent complex of strain-free ligand. Rates vary by a factor of ∼6 across ∼340 pN of force applied to the complexes. The crystal structures and DFT calculations support that force-induced perturbation of the geometry of the reactant is negligible. The force-rate relationship observed is mainly attributed to the coupling of force to nuclear motion comprising the reaction coordinate. These observations inform the development of catalysts whose activity can be tuned by an external force that is adjusted within a catalytic cycle.
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Affiliation(s)
- Liqi Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Yichen Yu
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Anton O Razgoniaev
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Patricia N Johnson
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Chenxu Wang
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Yancong Tian
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Ross A Widenhoefer
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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19
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Villarón D, Wezenberg SJ. Stiff-Stilbene Photoswitches: From Fundamental Studies to Emergent Applications. Angew Chem Int Ed Engl 2020; 59:13192-13202. [PMID: 32222016 PMCID: PMC7496324 DOI: 10.1002/anie.202001031] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Indexed: 12/19/2022]
Abstract
Stiff-stilbene, a sterically restricted fused ring analogue of stilbene, has been regularly used as a model compound in theoretical studies of stilbene photoisomerization. Lately, owing to its excellent photoswitching properties, it is increasingly being applied to reversibly control the properties and function of chemical as well as biological systems. Stiff-stilbene photoswitches possess a number of advantageous properties including a high quantum yield for photoisomerization and a high thermal stability. Furthermore, they undergo a large geometrical change upon isomerization and their synthesis is straightforward. Herein, we provide an overview of the basic properties of stiff-stilbene and of recent applications in supramolecular chemistry, catalysis, and biological systems.
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Affiliation(s)
- David Villarón
- Leiden Institute of ChemistryLeiden UniversityEinsteinweg 55, 2333CCLeidenThe Netherlands
| | - Sander J. Wezenberg
- Leiden Institute of ChemistryLeiden UniversityEinsteinweg 55, 2333CCLeidenThe Netherlands
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20
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Villarón D, Wezenberg SJ. Stiff‐Stilbene Photoswitches: From Fundamental Studies to Emergent Applications. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- David Villarón
- Leiden Institute of Chemistry Leiden University Einsteinweg 55, 2333 CC Leiden The Netherlands
| | - Sander J. Wezenberg
- Leiden Institute of Chemistry Leiden University Einsteinweg 55, 2333 CC Leiden The Netherlands
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21
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de Jong J, Feringa BL, Wezenberg SJ. Light-Modulated Self-Blockage of a Urea Binding Site in a Stiff-Stilbene Based Anion Receptor. Chemphyschem 2019; 20:3306-3310. [PMID: 31622003 PMCID: PMC6972635 DOI: 10.1002/cphc.201900917] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/14/2019] [Indexed: 12/16/2022]
Abstract
Anion binding to a receptor based on stiff-stilbene, which is equipped with a urea hydrogen bond donating group and a phosphate or phosphinate hydrogen bond accepting group, can be controlled by light. In one photoaddressable state (E isomer) the urea binding site is available for binding, while in the other (Z isomer) it is blocked because of an intramolecular interaction with its hydrogen bond accepting motif. This intramolecular interaction is supported by DFT calculations and 1 H NMR titrations reveal a significantly lower anion binding strength for the state in which anion binding is blocked. Furthermore, the molecular switching process has been studied in detail by UV/Vis and NMR spectroscopy. The presented approach opens up new opportunities toward the development of photoresponsive anion receptors.
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Affiliation(s)
- Jorn de Jong
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
| | - Ben L. Feringa
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
| | - Sander J. Wezenberg
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Leiden Institute of ChemistryLeiden UniversityEinsteinweg 552333 CCLeidenThe Netherlands
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22
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23
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Affiliation(s)
- Cai‐Li Sun
- Department of ChemistryUniversity of Liverpool Liverpool L69 7ZD United Kingdom
| | - Chenxu Wang
- Department of ChemistryUniversity of Liverpool Liverpool L69 7ZD United Kingdom
| | - Roman Boulatov
- Department of ChemistryUniversity of Liverpool Liverpool L69 7ZD United Kingdom
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24
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25
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Harada Y, Wang Z, Kumashiro S, Hatano S, Abe M. Extremely Long Lived Localized Singlet Diradicals in a Macrocyclic Structure: A Case Study on the Stretch Effect. Chemistry 2018; 24:14808-14815. [DOI: 10.1002/chem.201803076] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 07/14/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Yuta Harada
- Department of Chemistry; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima, Hiroshima 739-8526 Japan
| | - Zhe Wang
- Department of Chemistry; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima, Hiroshima 739-8526 Japan
| | - Shunsuke Kumashiro
- Department of Chemistry; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima, Hiroshima 739-8526 Japan
| | - Sayaka Hatano
- Department of Chemistry; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima, Hiroshima 739-8526 Japan
| | - Manabu Abe
- Department of Chemistry; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima, Hiroshima 739-8526 Japan
- Hiroshima University Research Center for, Photo-Drug-Delivery Systems (HiU-P-DDS); 1-3-1 Kagamiyama Higashi-Hiroshima, Hiroshima 739-8526 Japan
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26
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Han T, Deng H, Qiu Z, Zhao Z, Zhang H, Zou H, Leung NLC, Shan G, Elsegood MRJ, Lam JWY, Tang BZ. Facile Multicomponent Polymerizations toward Unconventional Luminescent Polymers with Readily Openable Small Heterocycles. J Am Chem Soc 2018; 140:5588-5598. [DOI: 10.1021/jacs.8b01991] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Ting Han
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Haiqin Deng
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Zijie Qiu
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Zheng Zhao
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Haoke Zhang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Hang Zou
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Nelson L. C. Leung
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Guogang Shan
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Mark R. J. Elsegood
- Chemistry Department, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K
| | - Jacky W. Y. Lam
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
| | - Ben Zhong Tang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing first RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
- China NSFC Center for Luminescence from Molecular Aggregates, SCUT-HKUST Joint Research Institute, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
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27
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Wollenhaupt M, Schran C, Krupička M, Marx D. Force‐Induced Catastrophes on Energy Landscapes: Mechanochemical Manipulation of Downhill and Uphill Bifurcations Explains the Ring‐Opening Selectivity of Cyclopropanes. Chemphyschem 2018; 19:837-847. [DOI: 10.1002/cphc.201701209] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Miriam Wollenhaupt
- Lehrstuhl für Theoretische ChemieRuhr-Universität Bochum 44780 Bochum Germany
| | - Christoph Schran
- Lehrstuhl für Theoretische ChemieRuhr-Universität Bochum 44780 Bochum Germany
| | - Martin Krupička
- Lehrstuhl für Theoretische ChemieRuhr-Universität Bochum 44780 Bochum Germany
- Present Address: Department of Organic ChemistryUniversity of Chemistry and Technology Technicka 5 16628 Prague Czech Republic
| | - Dominik Marx
- Lehrstuhl für Theoretische ChemieRuhr-Universität Bochum 44780 Bochum Germany
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28
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Akbulatov S, Tian Y, Huang Z, Kucharski TJ, Yang QZ, Boulatov R. Experimentally realized mechanochemistry distinct from force-accelerated scission of loaded bonds. Science 2018; 357:299-303. [PMID: 28729509 DOI: 10.1126/science.aan1026] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 06/20/2017] [Indexed: 12/11/2022]
Abstract
Stretching polymer chains accelerates dissociation of a variety of internal covalent bonds, to an extent that correlates well with the force experienced by the scissile bond. Recent theory has also predicted scenarios in which applied force accelerates dissociation of unloaded bonds and kinetically strengthens strained bonds. We report here unambiguous experimental validation of this hypothesis: Detailed kinetic measurements demonstrate that stretching phosphotriesters accelerates dissociation of the unloaded phosphorus-oxygen bond orthogonal to the pulling axis, whereas stretching organosiloxanes inhibits dissociation of the aligned loaded silicon-oxygen bonds. Qualitatively, the outcome is determined by phosphoester elongation and siloxane contraction along the pulling axis in the respective rate-determining transition states. Quantitatively, the results agree with a simple mechanochemical kinetics model.
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Affiliation(s)
- Sergey Akbulatov
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK
| | - Yancong Tian
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK
| | - Zhen Huang
- Department of Chemistry, University of Illinois, Urbana, IL 61801, USA
| | | | - Qing-Zheng Yang
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
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29
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Polymer Mechanochemistry: A New Frontier for Physical Organic Chemistry. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2018. [DOI: 10.1016/bs.apoc.2018.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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30
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Zhang H, Li X, Lin Y, Gao F, Tang Z, Su P, Zhang W, Xu Y, Weng W, Boulatov R. Multi-modal mechanophores based on cinnamate dimers. Nat Commun 2017; 8:1147. [PMID: 29079772 PMCID: PMC5660084 DOI: 10.1038/s41467-017-01412-8] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 09/15/2017] [Indexed: 01/06/2023] Open
Abstract
Mechanochemistry offers exciting opportunities for molecular-level engineering of stress-responsive properties of polymers. Reactive sites, sometimes called mechanophores, have been reported to increase the material toughness, to make the material mechanochromic or optically healable. Here we show that macrocyclic cinnamate dimers combine these productive stress-responsive modes. The highly thermally stable dimers dissociate on the sub-second timescale when subject to a stretching force of 1-2 nN (depending on isomer). Stretching a polymer of the dimers above this force more than doubles its contour length and increases the strain energy that the chain absorbs before fragmenting by at least 600 kcal per mole of monomer. The dissociation produces a chromophore and dimers are reformed upon irradiation, thus allowing optical healing of mechanically degraded parts of the material. The mechanochemical kinetics, single-chain extensibility, toughness and potentially optical properties of the dissociation products are tunable by synthetic modifications.
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Affiliation(s)
- Huan Zhang
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Xun Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012, China
| | - Yangju Lin
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Fei Gao
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Zhen Tang
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Peifeng Su
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Wenke Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012, China.
| | - Yuanze Xu
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian, 361005, China
| | - Wengui Weng
- Department of Chemistry, College of Chemistry and Engineering, Xiamen University, Xiamen, Fujian, 361005, China.
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Donnan Lab, G31, Crown St., Liverpool, L69 7ZD GB, UK.
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31
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Akbulatov S, Boulatov R. Experimental Polymer Mechanochemistry and its Interpretational Frameworks. Chemphyschem 2017; 18:1422-1450. [PMID: 28256793 DOI: 10.1002/cphc.201601354] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Indexed: 12/15/2022]
Abstract
Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of polymer chains confined to highly non-equilibrium stretched geometries by interactions with their surroundings. Macromolecular chains or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. An increasing amount of empirical data suggests that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self-strengthening and stress-reporting materials and mechanochemical cascades using purposefully designed monomers. This progress has not yet been matched by the development of conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. As a result, mechanistic and/or quantitative understanding of mechanochemical phenomena remains, with few exceptions, tentative. In this review we aim at systematizing reported macroscopic manifestations of polymer mechanochemistry, and critically assessing the interpretational framework that underlies their molecular rationalizations from a physical chemist's perspective. We propose a hierarchy of mechanochemical phenomena which may guide the development of multiscale models of mechanochemical reactivity to match the breadth and utility of the Eyring equation of chemical kinetics. We discuss the limitations of the approaches to quantifying and validating mechanochemical reactivity, with particular focus on sonicated polymer solutions, in order to identify outstanding questions that need to be solved for polymer mechanochemistry to become a rigorous, quantitative field. We conclude by proposing 7 problems whose solution may have a disproportionate impact on the development of polymer mechanochemistry.
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Affiliation(s)
- Sergey Akbulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
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32
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Boulatov R. The Challenges and Opportunities of Contemporary Polymer Mechanochemistry. Chemphyschem 2017; 18:1419-1421. [PMID: 28323365 DOI: 10.1002/cphc.201700127] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Roman Boulatov
- Chemistry Department, University of Liverpool, Liverpool, L69 7ZD, UK
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33
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Fernández-González MÁ, Rivero D, García-Iriepa C, Sampedro D, Frutos LM. Mechanochemical Tuning of Pyrene Absorption Spectrum Using Force Probes. J Chem Theory Comput 2017; 13:727-736. [DOI: 10.1021/acs.jctc.6b01020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | - Daniel Rivero
- Química
Física, Universidad de Alcalá, E-28871 Alcalá
de Henares, Madrid, Spain
| | - Cristina García-Iriepa
- Química
Física, Universidad de Alcalá, E-28871 Alcalá
de Henares, Madrid, Spain
- Departamento
de Química, Centro de Investigación en Síntesis Química (CISQ), Madre de Dios, 53, E-26006 Logroño, Spain
| | - Diego Sampedro
- Departamento
de Química, Centro de Investigación en Síntesis Química (CISQ), Madre de Dios, 53, E-26006 Logroño, Spain
| | - Luis Manuel Frutos
- Química
Física, Universidad de Alcalá, E-28871 Alcalá
de Henares, Madrid, Spain
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34
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Wang Y, Sun CL, Niu LY, Wu LZ, Tung CH, Chen YZ, Yang QZ. Photoresponsive AA/BB supramolecular polymers comprising stiff-stilbene based guests and bispillar[5]arenes. Polym Chem 2017. [DOI: 10.1039/c7py00326a] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We report a novel photoresponsive AA/BB supramolecular polymer comprising stiff-stilbene bridged guests and disulfide-bridged bispillar[5]arenes.
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Affiliation(s)
- Yuan Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Cai-Li Sun
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Li-Ya Niu
- Key Laboratory of Radiopharmaceuticals
- Ministry of Education
- College of Chemistry
- Beijing Normal University
- Beijing 100875
| | - Li-Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Chen-Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Yu-Zhe Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Qing-Zheng Yang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
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35
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Wang J, Kouznetsova TB, Boulatov R, Craig SL. Mechanical gating of a mechanochemical reaction cascade. Nat Commun 2016; 7:13433. [PMID: 27848956 PMCID: PMC5116086 DOI: 10.1038/ncomms13433] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/04/2016] [Indexed: 01/22/2023] Open
Abstract
Covalent polymer mechanochemistry offers promising opportunities for the control and engineering of reactivity. To date, covalent mechanochemistry has largely been limited to individual reactions, but it also presents potential for intricate reaction systems and feedback loops. Here we report a molecular architecture, in which a cyclobutane mechanophore functions as a gate to regulate the activation of a second mechanophore, dichlorocyclopropane, resulting in a mechanochemical cascade reaction. Single-molecule force spectroscopy, pulsed ultrasonication experiments and DFT-level calculations support gating and indicate that extra force of >0.5 nN needs to be applied to a polymer of gated gDCC than of free gDCC for the mechanochemical isomerization gDCC to proceed at equal rate. The gating concept provides a mechanism by which to regulate stress-responsive behaviours, such as load-strengthening and mechanochromism, in future materials designs.
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Affiliation(s)
- Junpeng Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | | | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK
| | - Stephen L. Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
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36
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Stauch T, Dreuw A. Advances in Quantum Mechanochemistry: Electronic Structure Methods and Force Analysis. Chem Rev 2016; 116:14137-14180. [PMID: 27767298 DOI: 10.1021/acs.chemrev.6b00458] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In quantum mechanochemistry, quantum chemical methods are used to describe molecules under the influence of an external force. The calculation of geometries, energies, transition states, reaction rates, and spectroscopic properties of molecules on the force-modified potential energy surfaces is the key to gain an in-depth understanding of mechanochemical processes at the molecular level. In this review, we present recent advances in the field of quantum mechanochemistry and introduce the quantum chemical methods used to calculate the properties of molecules under an external force. We place special emphasis on quantum chemical force analysis tools, which can be used to identify the mechanochemically relevant degrees of freedom in a deformed molecule, and spotlight selected applications of quantum mechanochemical methods to point out their synergistic relationship with experiments.
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Affiliation(s)
- Tim Stauch
- Interdisciplinary Center for Scientific Computing , Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing , Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
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37
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Kim YY, Carloni JD, Demarchi B, Sparks D, Reid DG, Kunitake ME, Tang CC, Duer MJ, Freeman CL, Pokroy B, Penkman K, Harding JH, Estroff LA, Baker SP, Meldrum FC. Tuning hardness in calcite by incorporation of amino acids. NATURE MATERIALS 2016; 15:903-910. [PMID: 27135858 DOI: 10.1038/nmat4631] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/24/2016] [Indexed: 06/05/2023]
Abstract
Structural biominerals are inorganic/organic composites that exhibit remarkable mechanical properties. However, the structure-property relationships of even the simplest building unit-mineral single crystals containing embedded macromolecules-remain poorly understood. Here, by means of a model biomineral made from calcite single crystals containing glycine (0-7 mol%) or aspartic acid (0-4 mol%), we elucidate the origin of the superior hardness of biogenic calcite. We analysed lattice distortions in these model crystals by using X-ray diffraction and molecular dynamics simulations, and by means of solid-state nuclear magnetic resonance show that the amino acids are incorporated as individual molecules. We also demonstrate that nanoindentation hardness increased with amino acid content, reaching values equivalent to their biogenic counterparts. A dislocation pinning model reveals that the enhanced hardness is determined by the force required to cut covalent bonds in the molecules.
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Affiliation(s)
- Yi-Yeoun Kim
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - Joseph D Carloni
- Department of Materials Science and Engineering, 214 Bard Hall, Cornell University, Ithaca, New York 14853, USA
| | - Beatrice Demarchi
- BioArCh, Departments of Chemistry and Archaeology, University of York, York YO10 5DD, UK
| | - David Sparks
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
| | - David G Reid
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Miki E Kunitake
- Department of Materials Science and Engineering, 214 Bard Hall, Cornell University, Ithaca, New York 14853, USA
| | - Chiu C Tang
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - Melinda J Duer
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Colin L Freeman
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
| | - Boaz Pokroy
- Department of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion Israel Institute of Technology, Haifa 32000, Israel
| | - Kirsty Penkman
- BioArCh, Departments of Chemistry and Archaeology, University of York, York YO10 5DD, UK
| | - John H Harding
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
| | - Lara A Estroff
- Department of Materials Science and Engineering, 214 Bard Hall, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, 420 Physical Sciences Building, Ithaca, New York 14853, USA
| | - Shefford P Baker
- Department of Materials Science and Engineering, 214 Bard Hall, Cornell University, Ithaca, New York 14853, USA
| | - Fiona C Meldrum
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
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38
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Kouznetsova TB, Wang J, Craig SL. Combined Constant-Force and Constant-Velocity Single-Molecule Force Spectroscopy of the Conrotatory Ring Opening Reaction of Benzocyclobutene. Chemphyschem 2016; 18:1486-1489. [PMID: 27348210 DOI: 10.1002/cphc.201600463] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Indexed: 11/09/2022]
Abstract
Single-molecule force spectroscopy (SMFS) of multi-mechanophore polymers has been used to provide kinetic and mechanistic insights into mechanochemical reactions. Whereas biological systems have benefitted from force clamp spectroscopy, synthetic polymers have been studied primarily with constant-velocity methods. Here, force clamp SMFS is applied to the mechanically accelerated conrotatory ring opening of benzocyclobutene, and a comparison with constant-velocity SMFS extends the range of available rate-versus-force data and corroborates the use of constant-velocity SMFS to extract force dependencies.
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Affiliation(s)
| | - Junpeng Wang
- Department of Chemistry and the James Franck Institute, The University of Chicago, 929 E 57th Street, Chicago, Illinois, 60637, USA
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina, 27708, USA
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39
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Abstract
Loops undergoing thermal fluctuations are prevalent in nature. Ringlike or cross-linked polymers, cyclic macromolecules, and protein-mediated DNA loops all belong to this category. Stability of these molecules are generally described in terms of free energy, an average quantity, but it may also be impacted by local fluctuating forces acting within these systems. The full distribution of these forces can thus give us insights into mechanochemistry beyond the predictive capability of thermodynamics. In this paper, we study the force exerted by an inextensible semiflexible polymer constrained in a looped state. By using a simulation method termed "phase-space sampling," we generate the equilibrium distribution of chain conformations in both position and momentum space. We compute the constraint forces between the two ends of the loop in this chain ensemble using Lagrangian mechanics, and show that the mean of these forces is equal to the thermodynamic force. By analyzing kinetic and potential contributions to the forces, we find that the mean force acts in the direction of increasing extension not because of bending stress, but in spite of it. Furthermore, we obtain a distribution of constraint forces as a function of chain length, extension, and stiffness. Notably, increasing contour length decreases the average force, but the additional freedom allows fluctuations in the constraint force to increase. The force distribution is asymmetric and falls off less sharply than a Gaussian distribution. Our work exemplifies a system where large-amplitude fluctuations occur in a way unforeseen by a purely thermodynamic framework, and offers computational tools useful for efficient, unbiased simulation of a constrained system.
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Affiliation(s)
- James T Waters
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332-0430, USA
| | - Harold D Kim
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332-0430, USA
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40
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Tian Y, Boulatov R. Comment on T. Stauch, A. Dreuw, “Stiff-stilbene photoswitch ruptures bonds not by pulling but by local heating”, Phys. Chem. Chem. Phys., 2016,18, 15848. Phys Chem Chem Phys 2016; 18:26990-26993. [DOI: 10.1039/c6cp04696g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We explain why the key premise of the above-cited paper (“local heating”) is based on misunderstanding of how fast solutes thermalize, of how molecular strain affects reaction rates and of the role of force in the modern models of mechanochemical kinetics.
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Affiliation(s)
- Yancong Tian
- Chemistry Department
- University of Liverpool
- Liverpool
- UK
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41
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Li Y, Tse ECM, Barile CJ, Gewirth AA, Zimmerman SC. Photoresponsive molecular switch for regulating transmembrane proton-transfer kinetics. J Am Chem Soc 2015; 137:14059-62. [PMID: 26512414 DOI: 10.1021/jacs.5b10016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To control proton delivery across biological membranes, we synthesized a photoresponsive molecular switch and incorporated it in a lipid layer. This proton gate was reversibly activated with 390 nm light (Z-isomer) and then deactivated by 360 nm irradiation (E-isomer). In a lipid layer this stimuli responsive proton gate allowed the regulation of proton flux with irradiation to a lipid-buried O2 reduction electrocatalyst. Thus, the catalyst was turned on and off with the E-to-Z interconversion. This light-induced membrane proton delivery system may be useful in developing any functional device that performs proton-coupled electron-transfer reactions.
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Affiliation(s)
- Ying Li
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Edmund C M Tse
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Christopher J Barile
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Andrew A Gewirth
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.,International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University , Fukuoka 812-8581, Japan
| | - Steven C Zimmerman
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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42
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Tsvetkov N, Lu Q, Chen Y, Yildiz B. Accelerated oxygen exchange kinetics on Nd2NiO(4+δ) thin films with tensile strain along c-axis. ACS NANO 2015; 9:1613-1621. [PMID: 25651454 DOI: 10.1021/nn506279h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The influence of the lattice strain on the kinetics of the oxygen reduction reaction (ORR) was investigated at the surface of Nd2NiO4+δ (NNO). Nanoscale dense NNO thin films with tensile, compressive and no strain along the c-axis were fabricated by pulsed laser deposition on single-crystalline Y0.08Zr0.92O2 substrates. The ORR kinetics on the NNO thin film cathodes was investigated by electrochemical impedance spectroscopy at 360-420 °C in air. The oxygen exchange kinetics on the NNO films with tensile strain along the c-axis was found to be 2-10 times faster than that on the films with compressive strain along the c-axis. A larger concentration of oxygen interstitials (δ) is found in the tensile NNO films compared to the films with no strain or compressive strain, deduced from the measured chemical capacitance. This is consistent with the increase in the distance between the NdO rock-salt layers observed by transmission electron microscopy. The surface structure of the nonstrained and tensile strained films remained stable upon annealing in air at 500 °C, while a significant morphology change accompanied by the enrichment of Nd was found at the surface of the films with compressive strain. The faster ORR kinetics on the tensile strained NNO films was attributed to the ability of these films to incorporate oxygen interstitials more easily, and to the better stability of the surface chemistry in comparison to the nonstrained or compressively strained films.
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Affiliation(s)
- Nikolai Tsvetkov
- Laboratory for Electrochemical Interfaces, ‡Department of Nuclear Science and Engineering, §Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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43
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Krupička M, Marx D. Disfavoring Mechanochemical Reactions by Stress-Induced Steric Hindrance. J Chem Theory Comput 2015; 11:841-6. [DOI: 10.1021/ct501058a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Martin Krupička
- Lehrstuhl
für Theoretische
Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl
für Theoretische
Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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44
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Wollenhaupt M, Krupička M, Marx D. Should the Woodward-Hoffmann Rules be Applied to Mechanochemical Reactions? Chemphyschem 2015; 16:1593-7. [DOI: 10.1002/cphc.201500054] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Indexed: 11/06/2022]
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45
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Li Y, Sheiko SS. Molecular Mechanochemistry: Engineering and Implications of Inherently Strained Architectures. Top Curr Chem (Cham) 2015; 369:1-36. [PMID: 25805145 DOI: 10.1007/128_2015_627] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Mechanical activation of chemical bonds is usually achieved by applying external forces. However, nearly all molecules exhibit inherent strain of their chemical bonds and angles as a result of constraints imposed by covalent bonding and interactions with the surrounding environment. Particularly strong deformation of bonds and angles is observed in hyperbranched macromolecules caused by steric repulsion of densely grafted polymer branches. In addition to the tension amplification, macromolecular architecture allows for accurate control of strain distribution, which enables focusing of the internal mechanical tension to specific chemical bonds and angles. As such, chemically identical bonds in self-strained macromolecules become physically distinct because the difference in bond tension leads to the corresponding difference in the electronic structure and chemical reactivity of individual bonds within the same macromolecule. In this review, we outline different approaches to the design of strained macromolecules along with physical principles of tension management, including generation, amplification, and focusing of mechanical tension at specific chemical bonds.
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Affiliation(s)
- Yuanchao Li
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599-3290, USA
| | - Sergei S Sheiko
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599-3290, USA.
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46
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Kochhar GS, Heverly-Coulson GS, Mosey NJ. Theoretical Approaches for Understanding the Interplay Between Stress and Chemical Reactivity. Top Curr Chem (Cham) 2015; 369:37-96. [DOI: 10.1007/128_2015_648] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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47
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Kean ZS, Akbulatov S, Tian Y, Widenhoefer RA, Boulatov R, Craig SL. Photomechanical Actuation of Ligand Geometry in Enantioselective Catalysis. Angew Chem Int Ed Engl 2014; 53:14508-11. [DOI: 10.1002/anie.201407494] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/18/2014] [Indexed: 12/20/2022]
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48
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Kean ZS, Akbulatov S, Tian Y, Widenhoefer RA, Boulatov R, Craig SL. Photomechanical Actuation of Ligand Geometry in Enantioselective Catalysis. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201407494] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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49
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Wang J, Kouznetsova TB, Kean ZS, Fan L, Mar BD, Martínez TJ, Craig SL. A Remote Stereochemical Lever Arm Effect in Polymer Mechanochemistry. J Am Chem Soc 2014; 136:15162-5. [DOI: 10.1021/ja509585g] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Junpeng Wang
- Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | | | - Zachary S. Kean
- Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Lin Fan
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Brendan D. Mar
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Todd J. Martínez
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Stephen L. Craig
- Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
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50
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Smalø HS, Rybkin VV, Klopper W, Helgaker T, Uggerud E. Mechanochemistry: the effect of dynamics. J Phys Chem A 2014; 118:7683-94. [PMID: 25105205 DOI: 10.1021/jp504959z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Dynamical effects on the mechanochemistry of linear alkane chains, mimicking polyethylene, are studied by means of molecular dynamics simulations. Butane and octane are studied using density-functional theory (DFT), whereas higher homologues are studied using a simple one-dimensional model in which the molecules are represented by a linear chain of Morse potentials (LCM). The application of a fixed external force to a thermodynamically pre-equilibrated molecule leads to a preference for cleavage of the terminal C-C bonds, whereas a sudden application of the force favors bond breaking in the central part of the chain. In all cases, transition-state theory predicts higher bond-breaking rates than found from the more realistic molecular dynamics simulations. The event of bond dissociation is related to dynamic states involving symmetric vibrational modes. Such modes do in general have lower frequencies of vibration than antisymmetric modes, which explains the deviation between the statistical theory and the dynamics simulations. The good qualitative agreement between the DFT and LCM models makes the latter a useful tool to investigate the mechanochemistry of long polymer chains.
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Affiliation(s)
- Hans S Smalø
- Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo , P.O. Box 1033, N-0315 Oslo, Norway
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