1
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Zhang M, Nixon R, Schaufelberger F, Pirvu L, De Bo G, Leigh DA. Mechanical scission of a knotted polymer. Nat Chem 2024; 16:1366-1372. [PMID: 38649468 PMCID: PMC11321991 DOI: 10.1038/s41557-024-01510-3] [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: 11/13/2022] [Accepted: 03/18/2024] [Indexed: 04/25/2024]
Abstract
Molecular knots and entanglements form randomly and spontaneously in both biological and synthetic polymer chains. It is known that macroscopic materials, such as ropes, are substantially weakened by the presence of knots, but until now it has been unclear whether similar behaviour occurs on a molecular level. Here we show that the presence of a well-defined overhand knot in a polymer chain substantially increases the rate of scission of the polymer under tension (≥2.6× faster) in solution, because deformation of the polymer backbone induced by the tightening knot activates otherwise unreactive covalent bonds. The fragments formed upon severing of the knotted chain differ from those that arise from cleavage of a similar, but unknotted, polymer. Our solution studies provide experimental evidence that knotting can contribute to higher mechanical scission rates of polymers. It also demonstrates that entanglement design can be used to generate mechanophores that are among the most reactive described to date, providing opportunities to increase the reactivity of otherwise inert functional groups.
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Affiliation(s)
- Min Zhang
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Robert Nixon
- Department of Chemistry, University of Manchester, Manchester, UK
| | | | - Lucian Pirvu
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Guillaume De Bo
- Department of Chemistry, University of Manchester, Manchester, UK.
| | - David A Leigh
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.
- Department of Chemistry, University of Manchester, Manchester, UK.
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2
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Chen L, De Bo G. Pushing vs Pulling: The Unique Geometry of Mechanophore Activation in a Rotaxane Force Actuator. J Am Chem Soc 2024; 146:16381-16384. [PMID: 38848593 PMCID: PMC11191692 DOI: 10.1021/jacs.4c05168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/09/2024]
Abstract
Mechanophores (mechanosensitive molecules) are usually activated by pulling them with covalently attached polymers. A rotaxane actuator offers a new geometry of activation as the macrocycle pushes against a stoppering mechanophore. Here we compare both pulling and pushing activations and show that pushing is more efficient and selective than pulling. We found that the pulling activation of a bulky furan/maleimide adduct occurs via two competing dissociation pathways: retrocycloaddition and heterolytic cleavage (generating a trityl cation in the process), while the same adduct only cleaves by retrocycloaddition during pushing activation. These results further demonstrate the efficacy and versatility of rotaxane actuators.
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Affiliation(s)
- Lei Chen
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United
Kingdom
| | - Guillaume De Bo
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United
Kingdom
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3
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Wang H, Benter S, Dononelli W, Neudecker T. JEDI: A versatile code for strain analysis of molecular and periodic systems under deformation. J Chem Phys 2024; 160:152501. [PMID: 38639312 DOI: 10.1063/5.0199247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/07/2024] [Indexed: 04/20/2024] Open
Abstract
Stretching or compression can induce significant energetic, geometric, and spectroscopic changes in materials. To fully exploit these effects in the design of mechano- or piezo-chromic materials, self-healing polymers, and other mechanoresponsive devices, a detailed knowledge about the distribution of mechanical strain in the material is essential. Within the past decade, Judgement of Energy DIstribution (JEDI) analysis has emerged as a useful tool for this purpose. Based on the harmonic approximation, the strain energy in each bond length, bond angle, and dihedral angle of the deformed system is calculated using quantum chemical methods. This allows the identification of the force-bearing scaffold of the system, leading to an understanding of mechanochemical processes at the most fundamental level. Here, we present a publicly available code that generalizes the JEDI analysis, which has previously only been available for isolated molecules. Now, the code has been extended to two- and three-dimensional periodic systems, supramolecular clusters, and substructures of chemical systems under various types of deformation. Due to the implementation of JEDI into the Atomic Simulation Environment, the JEDI analysis can be interfaced with a plethora of program packages that allow the calculation of electronic energies for molecular systems and systems with periodic boundary conditions. The automated generation of a color-coded three-dimensional structure via the Visual Molecular Dynamics program allows insightful visual analyses of the force-bearing scaffold of the strained system.
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Affiliation(s)
- Henry Wang
- University of Bremen, Institute for Physical and Theoretical Chemistry, Leobener Straße 6, D-28359 Bremen, Germany
| | - Sanna Benter
- University of Bremen, Institute for Physical and Theoretical Chemistry, Leobener Straße 6, D-28359 Bremen, Germany
| | - Wilke Dononelli
- Hybrid Materials Interfaces Group, Am Fallturm 1, D-28359 Bremen, Germany
- Bremen Center for Computational Materials Science, Am Fallturm 1, D-28359 Bremen, Germany
- MAPEX Center for Materials and Processes, Bibliothekstraße 1, D-28359 Bremen, Germany
| | - Tim Neudecker
- University of Bremen, Institute for Physical and Theoretical Chemistry, Leobener Straße 6, D-28359 Bremen, Germany
- Bremen Center for Computational Materials Science, Am Fallturm 1, D-28359 Bremen, Germany
- MAPEX Center for Materials and Processes, Bibliothekstraße 1, D-28359 Bremen, Germany
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4
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Chen L, Nixon R, De Bo G. Force-controlled release of small molecules with a rotaxane actuator. Nature 2024; 628:320-325. [PMID: 38600268 PMCID: PMC11006608 DOI: 10.1038/s41586-024-07154-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 02/02/2024] [Indexed: 04/12/2024]
Abstract
Force-controlled release of small molecules offers great promise for the delivery of drugs and the release of healing or reporting agents in a medical or materials context1-3. In polymer mechanochemistry, polymers are used as actuators to stretch mechanosensitive molecules (mechanophores)4. This technique has enabled the release of molecular cargo by rearrangement, as a direct5,6 or indirect7-10 consequence of bond scission in a mechanophore, or by dissociation of cage11, supramolecular12 or metal complexes13,14, and even by 'flex activation'15,16. However, the systems described so far are limited in the diversity and/or quantity of the molecules released per stretching event1,2. This is due to the difficulty in iteratively activating scissile mechanophores, as the actuating polymers will dissociate after the first activation. Physical encapsulation strategies can be used to deliver a larger cargo load, but these are often subject to non-specific (that is, non-mechanical) release3. Here we show that a rotaxane (an interlocked molecule in which a macrocycle is trapped on a stoppered axle) acts as an efficient actuator to trigger the release of cargo molecules appended to its axle. The release of up to five cargo molecules per rotaxane actuator was demonstrated in solution, by ultrasonication, and in bulk, by compression, achieving a release efficiency of up to 71% and 30%, respectively, which places this rotaxane device among the most efficient release systems achieved so far1. We also demonstrate the release of three representative functional molecules (a drug, a fluorescent tag and an organocatalyst), and we anticipate that a large variety of cargo molecules could be released with this device. This rotaxane actuator provides a versatile platform for various force-controlled release applications.
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Affiliation(s)
- Lei Chen
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Robert Nixon
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Guillaume De Bo
- Department of Chemistry, University of Manchester, Manchester, UK.
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5
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Dong X, Zhang Z, Xiao H, Liu G, Lei SN, Wang Z, Yan X, Wang S, Tung CH, Wu LZ, Cong H. Assembly and Utility of a Drawstring-Mimetic Supramolecular Complex. Angew Chem Int Ed Engl 2024; 63:e202318368. [PMID: 38165266 DOI: 10.1002/anie.202318368] [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: 11/30/2023] [Revised: 12/20/2023] [Accepted: 01/02/2024] [Indexed: 01/03/2024]
Abstract
Inspired by the drawstring structure in daily life, here we report the development of a drawstring-mimetic supramolecular complex at the molecular scale. This complex consists of a rigid figure-of-eight macrocyclic host molecule and a flexible linear guest molecule which could interact through three-point non-covalent binding to form a highly selective and efficient host-guest assembly. The complex not only resembles the drawstring structure, but also mimics the properties of a drawstring with regard to deformations under external forces. The supramolecular drawstring can be utilized as an interlocked crosslinker for poly(methyl acrylate), and the corresponding polymer samples exhibit comprehensive enhancement of macroscopic mechanical performance including stiffness, strength, and toughness.
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Affiliation(s)
- Xiangyu Dong
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhaoming Zhang
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hongyan Xiao
- Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guoquan Liu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Sheng-Nan Lei
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhao Wang
- Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xuzhou Yan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shutao Wang
- Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of 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
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Li-Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Huan Cong
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100190, China
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6
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Muramatsu T, Shimizu S, Clough JM, Weder C, Sagara Y. Force-Induced Shuttling of Rotaxanes Controls Fluorescence Resonance Energy Transfer in Polymer Hydrogels. ACS APPLIED MATERIALS & INTERFACES 2023; 15:8502-8509. [PMID: 36732315 PMCID: PMC9940108 DOI: 10.1021/acsami.2c20904] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
The molecular shuttling function of rotaxanes can be exploited to design mechanoresponsive reporter molecules. Here, we report a new approach to such rotaxane-based mechanophores, in which the fluorescence resonance energy transfer (FRET) between a donor-acceptor pair is mechanically controlled. A cyclic molecule containing a green-light-emitting FRET donor connected to a red-light-emitting FRET acceptor was threaded onto an axle equipped with a quencher at its center and two stoppers in the peripheral positions. In the force-free state, the green emitter is located near the quencher so that charge transfer interactions or photo-induced electron transfer between the two moieties suppress green emission and prevent the FRET from the green to the red emitter. The mechanophore was covalently incorporated into a linear polyurethane-urea (PUU), and stretchable hydrogels were prepared by swelling this polymer with water. Upon deformation of the PUU hydrogels and under an excitation light that selectively excites the donor, the intensity of the red fluorescence increases, as a result of a force-induced separation of the green emitter from the quencher, which enables the FRET. The switching contrast is much more pronounced in the gels than in dry films, which is due to increased molecular mobility and hydrophobic effects in the hydrogel, which both promote the formation of inclusion complexes between the ring containing the green emitter and the quencher.
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Affiliation(s)
- Tatsuya Muramatsu
- Department
of Materials Science and Engineering, Tokyo
Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Shohei Shimizu
- Department
of Materials Science and Engineering, Tokyo
Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Jessica M. Clough
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg CH-1700, Switzerland
| | - Christoph Weder
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg CH-1700, Switzerland
| | - Yoshimitsu Sagara
- Department
of Materials Science and Engineering, Tokyo
Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
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7
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Cardosa-Gutierrez M, De Bo G, Duwez AS, Remacle F. Bond breaking of furan-maleimide adducts via a diradical sequential mechanism under an external mechanical force. Chem Sci 2023; 14:1263-1271. [PMID: 36756317 PMCID: PMC9891376 DOI: 10.1039/d2sc05051j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/27/2022] [Indexed: 01/06/2023] Open
Abstract
Substituted furan-maleimide Diels-Alder adducts are bound by dynamic covalent bonds that make them particularly attractive mechanophores. Thermally activated [4 + 2] retro-Diels-Alder (DA) reactions predominantly proceed via a concerted mechanism in the ground electronic state. We show that an asymmetric mechanical force along the anchoring bonds in both the endo and exo isomers of proximal dimethyl furan-maleimide adducts favors a sequential pathway. The switching from a concerted to a sequential mechanism occurs at external forces of ≈1 nN. The first bond rupture occurs for a projection of the pulling force on the scissile bond at ≈4.3 nN for the exo adduct and ≈3.8 nN for the endo one. The reaction is inhibited for external forces up to ≈3.4 nN for the endo adduct and 3.6 nN for the exo one after which it is activated. In the activated region, at 4 nN, the rupture rate of the first bond for the endo adduct is computed to be ≈3 orders of magnitude larger than for the exo one in qualitative agreement with recent sonication experiments [Z. Wang and S. L. Craig, Chem. Commun., 2019, 55, 12263-12266]. In the intermediate region of the path between the rupture of the first and the second bond, the lowest singlet state exhibits a diradical character for both adducts and is close in energy to a diradical triplet state. The computed values of spin-orbit coupling along the path are too small for inducing intersystem crossings. These findings open the way for the rational design of DA mechanophores for polymer science and photochemistry.
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Affiliation(s)
| | - Guillaume De Bo
- Department of Chemistry, University of ManchesterManchesterM13 9PLUK
| | - Anne-Sophie Duwez
- UR Molecular Systems, Department of Chemistry, University of Liège 4000 Liège Belgium
| | - Francoise Remacle
- UR Molecular Systems, Department of Chemistry, University of Liège 4000 Liège Belgium
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8
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Lloyd EM, Vakil JR, Yao Y, Sottos NR, Craig SL. Covalent Mechanochemistry and Contemporary Polymer Network Chemistry: A Marriage in the Making. J Am Chem Soc 2023; 145:751-768. [PMID: 36599076 DOI: 10.1021/jacs.2c09623] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Over the past 20 years, the field of polymer mechanochemistry has amassed a toolbox of mechanophores that translate mechanical energy into a variety of functional responses ranging from color change to small-molecule release. These productive chemical changes typically occur at the length scale of a few covalent bonds (Å) but require large energy inputs and strains on the micro-to-macro scale in order to achieve even low levels of mechanophore activation. The minimal activation hinders the translation of the available chemical responses into materials and device applications. The mechanophore activation challenge inspires core questions at yet another length scale of chemical control, namely: What are the molecular-scale features of a polymeric material that determine the extent of mechanophore activation? Further, how do we marry advances in the chemistry of polymer networks with the chemistry of mechanophores to create stress-responsive materials that are well suited for an intended application? In this Perspective, we speculate as to the potential match between covalent polymer mechanochemistry and recent advances in polymer network chemistry, specifically, topologically controlled networks and the hierarchical material responses enabled by multi-network architectures and mechanically interlocked polymers. Both fundamental and applied opportunities unique to the union of these two fields are discussed.
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Affiliation(s)
- Evan M Lloyd
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States
| | - Jafer R Vakil
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina27708, United States
| | - Yunxin Yao
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina27708, United States
| | - Nancy R Sottos
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina27708, United States.,Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina27708, United States
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9
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Zhang Z, You W, Li P, Zhao J, Guo Z, Xu T, Chen J, Yu W, Yan X. Insights into the Correlation of Microscopic Motions of [ c2]Daisy Chains with Macroscopic Mechanical Performance for Mechanically Interlocked Networks. J Am Chem Soc 2023; 145:567-578. [PMID: 36562646 DOI: 10.1021/jacs.2c11105] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Mimicking filament sliding in sarcomeres using artificial molecular muscles such as [c2]daisy chains has aroused increasing interest in developing advanced polymeric materials. Although few bistable [c2]daisy chain-based mechanically interlocked polymers (MIPs) with stimuli-responsive behaviors have been constructed, it remains a significant challenge to establish the relationship between microscopic responsiveness of [c2]daisy chains and macroscopic mechanical properties of the corresponding MIPs. Herein, we report two mechanically interlocked networks (MINs) consisting of dense [c2]daisy chains with individual extension (MIN-1) or contraction (MIN-2) conformations decoupled from a bistable precursor, which serve as model systems to address the challenge. Upon external force, the extended [c2]daisy chains in MIN-1 mainly undergo elastic deformation, which is able to assure the strength, elasticity, and creep resistance of the corresponding material. For the contracted [c2]daisy chains, long-range sliding motion occurs along with the release of latent alkyl chains between the two DB24C8 wheels, and accumulating lots of such microscopic motions endows MIN-2 with enhanced ductility and ability of energy dissipation. Therefore, by decoupling a bistable [c2]daisy chain into individual extended and contracted ones, we directly correlate the microscopic motion of [c2]daisy chains with macroscopic mechanical properties of MINs.
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Affiliation(s)
- Zhaoming Zhang
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Wei You
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Peitong Li
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Jun Zhao
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Zhewen Guo
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Tingjie Xu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Jieqi Chen
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Wei Yu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Xuzhou Yan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
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10
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Hertel R, Maftuhin W, Walter M, Sommer M. Conformer Ring Flip Enhances Mechanochromic Performance of ansa-Donor-Acceptor-Donor Mechanochromic Torsional Springs. J Am Chem Soc 2022; 144:21897-21907. [PMID: 36414534 DOI: 10.1021/jacs.2c06712] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mechanochromophores based on conformational changes of donor-acceptor-donor (DAD) springs allow sensing of forces acting on polymer chains by monotonic changes of absorbance or photoluminescence (PL) wavelength. Here, we identify a series of thiophene (D)-flanked quinoxalines (A) as molecular torsional springs for force sensing in bulk polymers at room temperature. The mode of DAD linkage to the polymer matrix and linker rigidity are key parameters that influence the efficacy of force transduction to the DAD spring and thus mechanochromic response, as probed by in situ PL spectroscopy of bulk films during stress-strain experiments. The largest shift of the PL maximum, and thus the highest sensitivity, is obtained from an ansa-DAD spring exhibiting bridged D units and a stiff A linker. Using detailed spectroscopy and density functional theory calculations, we reveal conformer redistribution in the form of a thiophene ring flip as the major part of the overall mechanochromic response. At forces as low as 27 pN at early stages of deformation, the ring flip precedes mechanically induced planarization of the ansa-DAD spring, the latter process producing a PL shift of 21 nm nN-1. Within the stress-strain diagram, the thiophene ring flip and DAD planarization are thus two separated processes that also cause irreversible and reversible mechanochromic responses, respectively, upon sample failure. As the thiophene ring flip requires much smaller forces than planarization of the DAD spring, such micromechanical motion gives access to sensing of tiny forces and expands both sensitivity and the force range of conformational mechanochromophores.
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Affiliation(s)
- Raphael Hertel
- Institute for Chemistry, Chemnitz University of Technology, Chemnitz09111, Germany
| | - Wafa Maftuhin
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, Freiburg79110, Germany.,Cluster of Excellence livMatS @ FIT, Freiburg79110, Germany
| | - Michael Walter
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, Freiburg79110, Germany.,Cluster of Excellence livMatS @ FIT, Freiburg79110, Germany.,Fraunhofer IWM, MikroTribologie Centrum μTC, Freiburg79108, Germany
| | - Michael Sommer
- Institute for Chemistry, Chemnitz University of Technology, Chemnitz09111, Germany
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11
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Luo SM, Barber RW, Overholts AC, Robb MJ. Competitive Activation Experiments Reveal Significantly Different Mechanochemical Reactivity of Furan–Maleimide and Anthracene–Maleimide Mechanophores. ACS POLYMERS AU 2022; 3:202-208. [PMID: 37065719 PMCID: PMC10103189 DOI: 10.1021/acspolymersau.2c00047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/01/2022] [Accepted: 11/01/2022] [Indexed: 11/23/2022]
Abstract
During the past two decades, our understanding of mechanochemical reactivity has advanced considerably. Nevertheless, an incomplete knowledge of structure-activity relationships and the principles that govern mechanochemical transformations limits molecular design. The experimental development of mechanophores has thus benefited from simple computational tools like CoGEF, from which quantitative metrics like rupture force can be extracted to estimate reactivity. Furan-maleimide (FM) and anthracene-maleimide (AM) Diels-Alder adducts are widely studied mechanophores that undergo retro-Diels-Alder reactions upon mechanical activation in polymers. Despite possessing significantly different thermal stability, similar rupture forces predicted by CoGEF calculations suggest that these compounds exhibit similar mechanochemical reactivity. Here, we directly probe the relative mechanochemical reactivity of FM and AM adducts through competitive activation experiments. Ultrasound-induced mechanochemical activation of bis-adduct mechanophores comprising covalently tethered FM and AM subunits reveals pronounced selectivity-as high as ∼13:1-for reaction of the FM adduct compared to the AM adduct. Computational models provide insight into the greater reactivity of the FM mechanophore, indicating a more efficient mechanochemical coupling for the FM adduct compared to the AM adduct. The methodology employed here to directly interrogate the relative reactivity of two different mechanophores using a tethered bis-adduct configuration may be useful for other systems where more common sonication-based approaches are limited by poor sensitivity.
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Affiliation(s)
- Stella M. Luo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Ross W. Barber
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Anna C. Overholts
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Maxwell J. Robb
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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12
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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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13
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Hsu CC, Hsia FC, Weber B, de Rooij MB, Bonn D, Brouwer AM. Local Shearing Force Measurement during Frictional Sliding Using Fluorogenic Mechanophores. J Phys Chem Lett 2022; 13:8840-8844. [PMID: 36112048 PMCID: PMC9531245 DOI: 10.1021/acs.jpclett.2c02010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/13/2022] [Indexed: 06/15/2023]
Abstract
When two macroscopic objects touch, the real contact typically consists of multiple surface asperities that are deformed under the pressure that holds the objects together. Application of a shear force makes the objects slide along each other, breaking the initial contacts. To investigate how the microscopic shear force at the asperity level evolves during the transition from static to dynamic friction, we apply a fluorogenic mechanophore to visualize and quantify the local interfacial shear force. When a contact is broken, the shear force is released and the molecules return to their dark state, allowing us to dynamically observe the evolution of the shear force at the sliding contacts. We find that the macroscopic coefficient of friction describes the microscopic friction well, and that slip propagates from the edge toward the center of the macroscopic contact area before sliding occurs. This allows for a local understanding of how surfaces start to slide.
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Affiliation(s)
- Chao-Chun Hsu
- van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Feng-Chun Hsia
- Advanced
Research Center for Nanolithography, Science Park 106, 1098 XG Amsterdam, The Netherlands
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bart Weber
- Advanced
Research Center for Nanolithography, Science Park 106, 1098 XG Amsterdam, The Netherlands
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Matthijn B. de Rooij
- Laboratory
for Surface Technology and Tribology, Department of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Daniel Bonn
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Albert M. Brouwer
- van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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14
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Kasori R, Watabe T, Aoki D, Otsuka H. Enhancement of Mechanophore Activation by Electrostatic Interaction. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ryosuke Kasori
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Takuma Watabe
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Daisuke Aoki
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Hideyuki Otsuka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
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15
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Williams MTJ, Morrill LC, Browne DL. Mechanochemical Organocatalysis: Do High Enantioselectivities Contradict What We Might Expect? CHEMSUSCHEM 2022; 15:e202102157. [PMID: 34767693 PMCID: PMC9300213 DOI: 10.1002/cssc.202102157] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/09/2021] [Indexed: 05/10/2023]
Abstract
Ball mills input energy to samples by pulverising the contents of the jar. Each impact on the sample or wall of the jar results in an instantaneous transmission of energy in the form of a temperature and pressure increase (volume reduction). Conversely, enantioselective organocatalytic reactions proceed through perceived delicate and well-organised transition states. Does there exist a dichotomy in the idea of enantioselective mechanochemical organocatalysis? This Review provides a survey of the literature reporting the combination of organocatalytic reactions with mechanochemical ball milling conditions. Where possible, direct comparisons of stirred in solution, stirred neat and ball milled processes are drawn with a particular focus on control of stereoselectivity.
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Affiliation(s)
- Matthew T. J. Williams
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityPark PlaceCardiffCF10 3ATUK
| | - Louis C. Morrill
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityPark PlaceCardiffCF10 3ATUK
| | - Duncan L. Browne
- Department of Pharmaceutical and Biological ChemistrySchool of PharmacyUniversity College London29–39 Brunswick Square, BloomsburyLondonWC1N 1AXUK
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16
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Gauthier M, Waelès P, Coutrot F. Post-Synthetic Macrocyclization of Rotaxane Building Blocks. Chempluschem 2021; 87:e202100458. [PMID: 34811956 DOI: 10.1002/cplu.202100458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/11/2021] [Indexed: 11/06/2022]
Abstract
Although not often encountered, cyclic interlocked molecules are appealing molecular targets because of their restrained tridimensional structure which is related to both the cyclic and interlocked shapes. Interlocked molecules such as rotaxane building blocks may be good candidates for post-synthetic intramolecular cyclization if the preservation of the mechanical bond ensures the interlocked architecture throughout the reaction. This is obviously the case if the modification does not involve the cleavage of either the macrocycle's main chain or the encircled part of the axle. However, among the post-synthetic reactions, the chemical linkage between two reactive sites belonging to embedded elements of rotaxanes still consists of an underexploited route to interlocked cyclic molecules. This Review lists the rare examples of macrocyclization through chemical connection between reactive sites belonging to a surrounding macrocycle and/or an encircled axle of interlocked rotaxanes.
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Affiliation(s)
- Maxime Gauthier
- Supramolecular Machines and Architectures Team, IBMM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
| | - Philip Waelès
- Supramolecular Machines and Architectures Team, IBMM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
| | - Frédéric Coutrot
- Supramolecular Machines and Architectures Team, IBMM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
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17
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Muramatsu T, Okado Y, Traeger H, Schrettl S, Tamaoki N, Weder C, Sagara Y. Rotaxane-Based Dual Function Mechanophores Exhibiting Reversible and Irreversible Responses. J Am Chem Soc 2021; 143:9884-9892. [PMID: 34162206 DOI: 10.1021/jacs.1c03790] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mechanochromic mechanophores permit the design of polymers that indicate mechanical events through optical signals. Here we report rotaxane-based supramolecular mechanophores that display both reversible and irreversible fluorescence changes. These responses are triggered by different forces and are achieved by exploiting the molecular shuttling function and force-induced dethreading of rotaxanes. The new rotaxane mechanophores are composed of a ring featuring a luminophore, which is threaded onto an axle with a matching quencher and two stoppers. In the stress-free state, the luminophore is preferentially located in the proximity of the quencher, and the emission is quenched. The luminophore slides away from the quencher when a force is applied and the fluorescence is switched on. This effect is reversible, unless the force is so high that the luminophore-carrying ring slips past the stopper and dethreading occurs. We show that the combination of judiciously selected ring and stopper moieties is crucial to attain interlocked structures that display such a dual response. PU elastomers that contain such doubly responsive rotaxanes exhibit reversible fluorescence changes over multiple loading-unloading cycles due to the shuttling function, whereas permanent changes are observed upon repeated deformations to high strains due to breakage of the mechanical bond upon dethreading of the ring from the axle. This response allows one, at least conceptually, to monitor the actual deformation of polymer materials and examine mechanical damage that was inflicted in the past on the basis of an optical signal.
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Affiliation(s)
- Tatsuya Muramatsu
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Yuji Okado
- Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Hanna Traeger
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Stephen Schrettl
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Nobuyuki Tamaoki
- Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Yoshimitsu Sagara
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.,JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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18
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Küng R, Pausch T, Rasch D, Göstl R, Schmidt BM. Mechanochemische Freisetzung nichtkovalent gebundener Gäste aus einem mit Polymerketten dekorierten supramolekularen Käfig. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102383] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Robin Küng
- Institut für Organische Chemie und Makromolekulare Chemie Heinrich-Heine-Universität Düsseldorf Universitätsstraße 1 40225 Düsseldorf Deutschland
| | - Tobias Pausch
- Institut für Organische Chemie und Makromolekulare Chemie Heinrich-Heine-Universität Düsseldorf Universitätsstraße 1 40225 Düsseldorf Deutschland
| | - Dustin Rasch
- DWI – Leibniz-Institut für Interaktive Materialien Forckenbeckstraße 50 52056 Aachen Deutschland
- Institut für Technische und Makromolekulare Chemie RWTH Aachen University Worringerweg 1 52074 Aachen Deutschland
| | - Robert Göstl
- DWI – Leibniz-Institut für Interaktive Materialien Forckenbeckstraße 50 52056 Aachen Deutschland
| | - Bernd M. Schmidt
- Institut für Organische Chemie und Makromolekulare Chemie Heinrich-Heine-Universität Düsseldorf Universitätsstraße 1 40225 Düsseldorf Deutschland
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19
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Küng R, Pausch T, Rasch D, Göstl R, Schmidt BM. Mechanochemical Release of Non-Covalently Bound Guests from a Polymer-Decorated Supramolecular Cage. Angew Chem Int Ed Engl 2021; 60:13626-13630. [PMID: 33729649 PMCID: PMC8251918 DOI: 10.1002/anie.202102383] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/08/2021] [Indexed: 12/21/2022]
Abstract
Supramolecular coordination cages show a wide range of useful properties including, but not limited to, complex molecular machine-like operations, confined space catalysis, and rich host-guest chemistries. Here we report the uptake and release of non-covalently encapsulated, pharmaceutically-active cargo from an octahedral Pd cage bearing polymer chains on each vertex. Six poly(ethylene glycol)-decorated bipyridine ligands are used to assemble an octahedral PdII6 (TPT)4 cage. The supramolecular container encapsulates progesterone and ibuprofen within its hydrophobic nanocavity and is activated by shear force produced by ultrasonication in aqueous solution entailing complete cargo release upon rupture, as shown by NMR and GPC analyses.
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Affiliation(s)
- Robin Küng
- Institut für Organische Chemie und Makromolekulare ChemieHeinrich-Heine-Universität DüsseldorfUniversitätsstrasse 140225DüsseldorfGermany
| | - Tobias Pausch
- Institut für Organische Chemie und Makromolekulare ChemieHeinrich-Heine-Universität DüsseldorfUniversitätsstrasse 140225DüsseldorfGermany
| | - Dustin Rasch
- DWI—Leibniz Institute for Interactive MaterialsForckenbeckstrasse 5052056AachenGermany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 152074AachenGermany
| | - Robert Göstl
- DWI—Leibniz Institute for Interactive MaterialsForckenbeckstrasse 5052056AachenGermany
| | - Bernd M. Schmidt
- Institut für Organische Chemie und Makromolekulare ChemieHeinrich-Heine-Universität DüsseldorfUniversitätsstrasse 140225DüsseldorfGermany
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20
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Sagara Y, Traeger H, Li J, Okado Y, Schrettl S, Tamaoki N, Weder C. Mechanically Responsive Luminescent Polymers Based on Supramolecular Cyclophane Mechanophores. J Am Chem Soc 2021; 143:5519-5525. [PMID: 33784073 DOI: 10.1021/jacs.1c01328] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A new approach to cyclophane-based supramolecular mechanophores is presented. We report a mechanically responsive cyclic motif that contains two fluorescent 1,6-bis(phenylethynyl)pyrene moieties that are capable of forming intramolecular excimers. The emission spectra of dilute solutions of this cyclophane and a polyurethane elastomer into which a small amount of the mechanophore (0.08 wt %) had been covalently integrated are dominated by excimer emission. Films of the cyclophane-containing polyurethane also display a considerable portion of excimer emission, but upon deformation, the fluorescence becomes monomer-dominated and a perceptible change from cyan to blue is observed. The response is instant, reversible, and consistent with a mechanically induced change of the molecular conformation of the mechanophore so that the excimer-promoting interactions between the luminophores are suppressed. In-depth investigations show a correlation between the applied strain and the emission color, which can conveniently be expressed by the ratio of monomer to excimer emission intensity. The current study suggests that cyclophanes can be utilized to develop various supramolecular mechanophores that detect and visualize weak forces occurring in polymeric materials or generated by living tissues.
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Affiliation(s)
- Yoshimitsu Sagara
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan
- JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Hanna Traeger
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Jie Li
- Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-Ku, Sapporo, Hokkaido 001-0020, Japan
| | - Yuji Okado
- Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-Ku, Sapporo, Hokkaido 001-0020, Japan
| | - Stephen Schrettl
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Nobuyuki Tamaoki
- Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-Ku, Sapporo, Hokkaido 001-0020, Japan
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
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21
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Abstract
In mechanochemistry, molecules under tension can react in unexpected ways. The reactivity of mechanophores (mechanosensitive molecules) can be controlled using various geometric or electronic factors. Often these factors affect the rate of mechanical activation but sometimes give rise to alternative reaction pathways. Here we show that a simple isotope substitution (H to D) leads to a reversal of selectivity in the activation of a mechanophore. Remarkably this isotope effect is not kinetic in nature but emerges from dynamic effects in which deuteration reduces the ability of the reactant to follow a post-transition-state concerted trajectory on the bifurcated force-modified potential energy surface. These results give a new insight into the reactivity of molecules under tension.
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Affiliation(s)
- Robert Nixon
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Guillaume De Bo
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
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22
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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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23
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Ayer MA, Verde-Sesto E, Liu CH, Weder C, Lattuada M, Simon YC. Modeling ultrasound-induced molecular weight decrease of polymers with multiple scissile azo-mechanophores. Polym Chem 2021. [DOI: 10.1039/d1py00420d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Selective and non-selective chain scission compete upon ultrasonic treatment of polymers with randomly distributed azo units.
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Affiliation(s)
- Mathieu A. Ayer
- Adolphe Merkle Institute
- University of Fribourg
- 1700 Fribourg
- Switzerland
| | - Ester Verde-Sesto
- Adolphe Merkle Institute
- University of Fribourg
- 1700 Fribourg
- Switzerland
- Centro de Física de Materiales (CSIC
| | - Cheyenne H. Liu
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- 118 College Dr
- USA
| | - Christoph Weder
- Adolphe Merkle Institute
- University of Fribourg
- 1700 Fribourg
- Switzerland
| | - Marco Lattuada
- Adolphe Merkle Institute
- University of Fribourg
- 1700 Fribourg
- Switzerland
- Department of Chemistry
| | - Yoan C. Simon
- Adolphe Merkle Institute
- University of Fribourg
- 1700 Fribourg
- Switzerland
- School of Polymer Science and Engineering
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24
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Sandoval-Torrientes R, Carr T, De Bo G. A Mechanochromic Hydrogen-Bonded Rotaxane. Macromol Rapid Commun 2020; 42:e2000447. [PMID: 33043523 DOI: 10.1002/marc.202000447] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/09/2020] [Indexed: 01/08/2023]
Abstract
Tensile forces influence a variety of important biological processes and force sensors are required to study these processes in vivo. Current force sensors are often tailor-made for a specific application, or activate at much higher forces than those observed at the cellular or tissue level. A versatile force sensor, with tunable mechanical and optical properties, activated at low pN forces will be ideal. In this communication, a new mechanoresponsive fluorescent hydrogen-bonded rotaxane, built around a maleimide dye, is reported. Its force-sensing properties are demonstrated in a polyacrylamide gel, a synthetic model of living tissue.
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Affiliation(s)
| | - ThomasR Carr
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Guillaume De Bo
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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25
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Affiliation(s)
- Guillaume De Bo
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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26
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Klein IM, Husic CC, Kovács DP, Choquette NJ, Robb MJ. Validation of the CoGEF Method as a Predictive Tool for Polymer Mechanochemistry. J Am Chem Soc 2020; 142:16364-16381. [DOI: 10.1021/jacs.0c06868] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Isabel M. Klein
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Corey C. Husic
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Dávid P. Kovács
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Nicolas J. Choquette
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Maxwell J. Robb
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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27
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28
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Abstract
Mechanophores (mechanoresponsive molecules) offer great promises for the development of smart force-responsive materials. The activity of a mechanophore can be tuned by altering its structure or the composition of the actuating polymer. Here we show that a [2]catenane can act as a mechanical protecting group by diverting tensional forces away from a mechanically active functional group embedded in one of its rings. This property emerges from the mobility of the two rings of the catenane, which are able to rotate along each other until the tension equalizes over the entirety of the catenated framework. This approach provides a new way to control the mechanical activity of a mechanophore.
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Affiliation(s)
- Min Zhang
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Guillaume De Bo
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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29
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Akae Y, Iijima K, Tanaka M, Tarao T, Takata T. Main Chain-Type Polyrotaxanes Derived from Cyclodextrin-Based Pseudo[3]rotaxane Diamine and Macromolecular Diisocyanate: Synthesis, Modification, and Characterization. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yosuke Akae
- School of Chemical Science and Engineering, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8503, Japan
| | - Keisuke Iijima
- School of Chemical Science and Engineering, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8503, Japan
| | - Mami Tanaka
- Sports Business Headquarters, Sumitomo Rubber Industries, Ltd., 6-9, 3-chome, Wakinohama-cho, Chuo-ku, Kobe 651-0072, Japan
| | - Toshiyuki Tarao
- Sports Business Headquarters, Sumitomo Rubber Industries, Ltd., 6-9, 3-chome, Wakinohama-cho, Chuo-ku, Kobe 651-0072, Japan
| | - Toshikazu Takata
- School of Chemical Science and Engineering, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8503, Japan
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30
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Jung S, Yoon HJ. Mechanical Force Induces Ylide-Free Cycloaddition of Nonscissible Aziridines. Angew Chem Int Ed Engl 2020; 59:4883-4887. [PMID: 31944507 DOI: 10.1002/anie.201915438] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/07/2020] [Indexed: 11/08/2022]
Abstract
The application of aziridines as nonvulnerable mechanophores is reported. Upon exposure to a mechanical force, stereochemically pure nonactivated aziridines incorporated into the backbone of a macromolecule do not undergo cis-trans isomerization, thus suggesting retention of the ring structure under force. Nonetheless, aziridines react with a dipolarophile and seem not to obey conventional reaction pathways that involve C-C or C-N bond cleavage prior to the cycloaddition. Our work demonstrates that a nonvulnerable chemical structure can be a mechanophore.
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Affiliation(s)
- Sangmin Jung
- Department of Chemistry, Korea University, Seoul, 02841, South Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul, 02841, South Korea
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31
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Zhang M, Shvetsova O, De Bo G. Expedient Synthesis of Heterobifunctional Triarylmethane Stoppers for Macromolecular Rotaxanes. J Org Chem 2020; 85:2770-2774. [PMID: 31971804 DOI: 10.1021/acs.joc.9b03063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Increasingly complex rotaxane-based molecular devices are interfaced with polymers and surfaces, but suitable bifunctional stoppering groups are lacking. Here, we report a two-step, high-yielding synthesis toward a new class of heterobifunctional triarylmethane stoppers. They possess hydroxyl and ester groups for further functionalization as well as halogen substituents conferring a diagnostic spectroscopic signature. Their utility was demonstrated with the synthesis of a chain-centered macromolecular rotaxane. This new stopper architecture should prove useful to connect rotaxanes with polymers and surfaces for applications in polymer mechanochemistry, single-molecule force spectroscopy, smart materials, and molecular machines.
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Affiliation(s)
- Min Zhang
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Olga Shvetsova
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Guillaume De Bo
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
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32
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33
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Izak-Nau E, Campagna D, Baumann C, Göstl R. Polymer mechanochemistry-enabled pericyclic reactions. Polym Chem 2020. [DOI: 10.1039/c9py01937e] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Polymer mechanochemical pericyclic reactions are reviewed with regard to their structural features and substitution prerequisites to the polymer framework.
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Affiliation(s)
- Emilia Izak-Nau
- DWI – Leibniz Institute for Interactive Materials
- 52056 Aachen
- Germany
| | - Davide Campagna
- DWI – Leibniz Institute for Interactive Materials
- 52056 Aachen
- Germany
- Institute for Technical and Macromolecular Chemistry
- RWTH Aachen University
| | - Christoph Baumann
- DWI – Leibniz Institute for Interactive Materials
- 52056 Aachen
- Germany
- Institute for Technical and Macromolecular Chemistry
- RWTH Aachen University
| | - Robert Göstl
- DWI – Leibniz Institute for Interactive Materials
- 52056 Aachen
- Germany
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34
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Stevenson R, Zhang M, De Bo G. Mechanical activation of polymers containing two adjacent mechanophores. Polym Chem 2020. [DOI: 10.1039/d0py00279h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polymers containing two adjacent mechanophores cleave at the same as a single-mechanophore chains.
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Affiliation(s)
| | - Min Zhang
- Department of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
| | - Guillaume De Bo
- Department of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
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35
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Lu Y, Aoki D, Sawada J, Kosuge T, Sogawa H, Otsuka H, Takata T. Visualization of the slide-ring effect: a study on movable cross-linking points using mechanochromism. Chem Commun (Camb) 2020; 56:3361-3364. [DOI: 10.1039/c9cc09452k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
To evaluate the ‘slide-ring’ effect in a rotaxane cross-linked network, we incorporated mechanochromophores into static and rotaxane cross-linking points and compared the mechanochromisms exhibited by the obtained polymers.
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Affiliation(s)
- Yi Lu
- Department of Chemical Science and Engineering
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - Daisuke Aoki
- Department of Chemical Science and Engineering
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - Jun Sawada
- Department of Chemical Science and Engineering
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - Takahiro Kosuge
- Department of Chemical Science and Engineering
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - Hiromitsu Sogawa
- Department of Chemical Science and Engineering
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - Hideyuki Otsuka
- Department of Chemical Science and Engineering
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - Toshikazu Takata
- Department of Chemical Science and Engineering
- Tokyo Institute of Technology
- Tokyo
- Japan
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36
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Affiliation(s)
- Min Zhang
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Guillaume De Bo
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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37
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Zhang Y, Ouyang Y, Luo Z, Dong S. Convenient, Column Chromatography-Free, and Effective Synthesis of Benzo-21-crown-7 and Its Derivatives. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900712] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yi Zhang
- College of Chemistry and Chemical Engineering; Hunan University; 410082 Changsha Hunan P. R. China
| | - Yunyun Ouyang
- College of Chemistry and Chemical Engineering; Hunan University; 410082 Changsha Hunan P. R. China
| | - Zheng Luo
- College of Chemistry and Chemical Engineering; Hunan University; 410082 Changsha Hunan P. R. China
| | - Shengyi Dong
- College of Chemistry and Chemical Engineering; Hunan University; 410082 Changsha Hunan P. R. China
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38
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Lin Y, Zhang Y, Wang Z, Craig SL. Dynamic Memory Effects in the Mechanochemistry of Cyclic Polymers. J Am Chem Soc 2019; 141:10943-10947. [DOI: 10.1021/jacs.9b03564] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yangju Lin
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Yudi Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Zi Wang
- 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
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39
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Sagara Y, Karman M, Seki A, Pannipara M, Tamaoki N, Weder C. Rotaxane-Based Mechanophores Enable Polymers with Mechanically Switchable White Photoluminescence. ACS CENTRAL SCIENCE 2019; 5:874-881. [PMID: 31139723 PMCID: PMC6535770 DOI: 10.1021/acscentsci.9b00173] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 05/05/2023]
Abstract
Three mechanoresponsive polyurethane elastomers whose blue, green, and orange photoluminescence can be reversibly turned on by mechanical force were prepared and combined to create a blend that exhibits deformation-induced white photoluminescence. The three polyurethanes contain rotaxane-based supramolecular mechanoluminophores based on π-extended pyrene, anthracene, or 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) luminophores, respectively, and 1,4,5,8-naphthalenetetracarboxylic diimide as an electronically matched quencher. Each polymer shows instantly reversible, strain-dependent switching of its photoluminescence intensity when stretched and relaxed, as deformation leads to a spatial separation of the luminophore and quencher. The present study shows that the photoluminescence color can easily be tailored by variation of the luminophore and also by combining several mechanophores in one material and demonstrates that adaptability is a key advantage of supramolecular approaches to create mechanoresponsive polymers.
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Affiliation(s)
- Yoshimitsu Sagara
- Research
Institute for Electronic Science, Hokkaido
University, N20, W10, Kita-Ku, Sapporo 001-0020, Japan
- JST-PRESTO, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan
| | - Marc Karman
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Atsushi Seki
- Research
Institute for Electronic Science, Hokkaido
University, N20, W10, Kita-Ku, Sapporo 001-0020, Japan
| | - Mehboobali Pannipara
- Research
Institute for Electronic Science, Hokkaido
University, N20, W10, Kita-Ku, Sapporo 001-0020, Japan
- Department
of Chemistry, Faculty of Science, King Khalid
University, Guraiger, Abha 61413, Saudi Arabia
| | - Nobuyuki Tamaoki
- Research
Institute for Electronic Science, Hokkaido
University, N20, W10, Kita-Ku, Sapporo 001-0020, Japan
| | - Christoph Weder
- Adolphe
Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
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40
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Sluysmans D, Stoddart JF. The Burgeoning of Mechanically Interlocked Molecules in Chemistry. TRENDS IN CHEMISTRY 2019. [DOI: 10.1016/j.trechm.2019.02.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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