1
|
Sun Y, Neary WJ, Huang X, Kouznetsova TB, Ouchi T, Kevlishvili I, Wang K, Chen Y, Kulik HJ, Craig SL, Moore JS. A Thermally Stable SO 2-Releasing Mechanophore: Facile Activation, Single-Event Spectroscopy, and Molecular Dynamic Simulations. J Am Chem Soc 2024; 146:10943-10952. [PMID: 38581383 DOI: 10.1021/jacs.4c02139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2024]
Abstract
Polymers that release small molecules in response to mechanical force are promising candidates as next-generation on-demand delivery systems. Despite advancements in the development of mechanophores for releasing diverse payloads through careful molecular design, the availability of scaffolds capable of discharging biomedically significant cargos in substantial quantities remains scarce. In this report, we detail a nonscissile mechanophore built from an 8-thiabicyclo[3.2.1]octane 8,8-dioxide (TBO) motif that releases one equivalent of sulfur dioxide (SO2) from each repeat unit. The TBO mechanophore exhibits high thermal stability but is activated mechanochemically using solution ultrasonication in either organic solvent or aqueous media with up to 63% efficiency, equating to 206 molecules of SO2 released per 143.3 kDa chain. We quantified the mechanochemical reactivity of TBO by single-molecule force spectroscopy and resolved its single-event activation. The force-coupled rate constant for TBO opening reaches ∼9.0 s-1 at ∼1520 pN, and each reaction of a single TBO domain releases a stored length of ∼0.68 nm. We investigated the mechanism of TBO activation using ab initio steered molecular dynamic simulations and rationalized the observed stereoselectivity. These comprehensive studies of the TBO mechanophore provide a mechanically coupled mechanism of multi-SO2 release from one polymer chain, facilitating the translation of polymer mechanochemistry to potential biomedical applications.
Collapse
Affiliation(s)
- Yunyan Sun
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - William J Neary
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Xiao Huang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tetsu Ouchi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Ilia Kevlishvili
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kecheng Wang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yingying Chen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Heather J Kulik
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Jeffrey S Moore
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
2
|
Wu Z, Bayón JL, Kouznetsova TB, Ouchi T, Barkovich KJ, Hsu SK, Craig SL, Steinmetz NF. Virus-like Particles Armored by an Endoskeleton. Nano Lett 2024; 24:2989-2997. [PMID: 38294951 DOI: 10.1021/acs.nanolett.3c03806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Many virus-like particles (VLPs) have good chemical, thermal, and mechanical stabilities compared to those of other biologics. However, their stability needs to be improved for the commercialization and use in translation of VLP-based materials. We developed an endoskeleton-armored strategy for enhancing VLP stability. Specifically, the VLPs of physalis mottle virus (PhMV) and Qβ were used to demonstrate this concept. We built an internal polymer "backbone" using a maleimide-PEG15-maleimide cross-linker to covalently interlink viral coat proteins inside the capsid cavity, while the native VLPs are held together by only noncovalent bonding between subunits. Endoskeleton-armored VLPs exhibited significantly improved thermal stability (95 °C for 15 min), increased resistance to denaturants (i.e., surfactants, pHs, chemical denaturants, and organic solvents), and enhanced mechanical performance. Single-molecule force spectroscopy demonstrated a 6-fold increase in rupture distance and a 1.9-fold increase in rupture force of endoskeleton-armored PhMV. Overall, this endoskeleton-armored strategy provides more opportunities for the development and applications of materials.
Collapse
Affiliation(s)
- Zhuohong Wu
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Center for Nano-ImmunoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, United States
- Shu and K. C. Chien and Peter Farrell Collaboratory, University of California, San Diego, La Jolla, California 92093, United States
| | - Jorge L Bayón
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Center for Nano-ImmunoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, United States
- Shu and K. C. Chien and Peter Farrell Collaboratory, University of California, San Diego, La Jolla, California 92093, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tetsu Ouchi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Krister J Barkovich
- Center for Nano-ImmunoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, United States
- Shu and K. C. Chien and Peter Farrell Collaboratory, University of California, San Diego, La Jolla, California 92093, United States
- Department of Radiology, University of California, San Diego, La Jolla, California 92093, United States
| | - Sean K Hsu
- Center for Nano-ImmunoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, United States
- Shu and K. C. Chien and Peter Farrell Collaboratory, University of California, San Diego, La Jolla, California 92093, United States
- Department of Molecular Biology, University of California, San Diego, La Jolla, California 92093, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Nicole F Steinmetz
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Center for Nano-ImmunoEngineering, University of California, San Diego, La Jolla, California 92093, United States
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, United States
- Shu and K. C. Chien and Peter Farrell Collaboratory, University of California, San Diego, La Jolla, California 92093, United States
- Department of Radiology, University of California, San Diego, La Jolla, California 92093, United States
- Department of Molecular Biology, University of California, San Diego, La Jolla, California 92093, United States
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States
- Institute for Materials Discovery and Design, University of California, San Diego, La Jolla, California 92093, United States
- Center for Engineering in Cancer, Institute for Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, United States
| |
Collapse
|
3
|
Lin Y, Kouznetsova TB, Foret AG, Craig SL. Solvent Polarity Effects on the Mechanochemistry of Spiropyran Ring Opening. J Am Chem Soc 2024; 146:3920-3925. [PMID: 38308653 DOI: 10.1021/jacs.3c11621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
The spiropyran mechanophore (SP) is employed as a reporter of molecular tension in a wide range of polymer matrices, but the influence of surrounding environment on the force-coupled kinetics of its ring opening has not been quantified. Here, we report single-molecule force spectroscopy studies of SP ring opening in five solvents that span normalized Reichardt solvent polarity factors (ETN) of 0.1-0.59. Individual multimechanophore polymers were activated under increasing tension at constant 300 nm s-1 displacement in an atomic force microscope. The extension results in a plateau in the force-extension curve, whose midpoint occurs at a transition force f* that corresponds to the force required to increase the rate constant of SP activation to approximately 30 s-1. More polar solvents lead to mechanochemical reactions that are easier to trigger; f* decreases across the series of solvents, from a high of 415 ± 13 pN in toluene to a low of 234 ± 9 pN in n-butanol. The trend in mechanochemical reactivity is consistent with the developing zwitterionic character on going from SP to the ring-opened merocyanine product. The force dependence of the rate constant (Δx‡) was calculated for all solvent cases and found to increase with ETN, which is interpreted to reflect a shift in the transition state to a later and more productlike position. The inferred shift in the transition state position is consistent with a double-well (two-step) reaction potential energy surface, in which the second step is rate determining, and the intermediate is more polar than the product.
Collapse
Affiliation(s)
- Yangju Lin
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Alex G Foret
- 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
| |
Collapse
|
4
|
Horst M, Meisner J, Yang J, Kouznetsova TB, Craig SL, Martínez TJ, Xia Y. Mechanochemistry of Pterodactylane. J Am Chem Soc 2024; 146:884-891. [PMID: 38131266 DOI: 10.1021/jacs.3c11293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Pterodactylane is a [4]-ladderane with substituents on the central rung. Comparing the mechanochemistry of the [4]-ladderane structure when pulled from the central rung versus the end rung revealed a striking difference in the threshold force of mechanoactivation: the threshold force is dramatically lowered from 1.9 nN when pulled on the end rung to 0.7 nN when pulled on the central rung. We investigated the bicyclic products formed from the mechanochemical activation of pterodactylane experimentally and computationally, which are distinct from the mechanochemical products of ladderanes being activated from the end rung. We compared the products of pterodactylane's mechanochemical and thermal activation to reveal differences and similarities in the mechanochemical and thermal pathways of pterodactylane transformation. Interestingly, we also discovered the presence of elementary steps that are accelerated or suppressed by force within the same mechanochemical reaction of pterodactylane, suggesting rich mechanochemical manifolds of multicyclic structures. We rationalized the greatly enhanced mechanochemical reactivity of the central rung of pterodactylane and discovered force-free ground state bond length to be a good low-cost predictor of the threshold force for cyclobutane-based mechanophores. These findings advance our understanding of mechanochemical reactivities and pathways, and they will guide future designs of mechanophores with low threshold forces to facilitate their applications in force-responsive materials.
Collapse
Affiliation(s)
- Matías Horst
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jan Meisner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Institute for Physical Chemistry, Department of Chemistry, Heinrich-Heine-Universität Düsseldorf, Düsseldorf D-40225, Germany
| | - Jinghui Yang
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Tatiana B Kouznetsova
- 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
| | - Todd J Martínez
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Yan Xia
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
5
|
Beech HK, Wang S, Sen D, Rota D, Kouznetsova TB, Arora A, Rubinstein M, Craig SL, Olsen BD. Reactivity-Guided Depercolation Processes Determine Fracture Behavior in End-Linked Polymer Networks. ACS Macro Lett 2023; 12:1685-1691. [PMID: 38038127 DOI: 10.1021/acsmacrolett.3c00559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
The fracture of polymer networks is tied to the molecular behavior of strands within the network, yet the specific molecular-level processes that determine the mechanical limits of a network remain elusive. Here, the question of reactivity-guided fracture is explored in otherwise indistinguishable end-linked networks by tuning the relative composition of strands with two different mechanochemical reactivities. Increasing the substitution of less mechanochemically reactive ("strong") strands into a network comprising more reactive ("weak") strands has a negligible impact on the fracture energy until the strong strand content reaches approximately 45%, at which point the fracture energy sharply increases with strong strand content. This aligns with the measured strong strand percolation threshold of 48 ± 3%, revealing that depercolation, or the loss of a percolated network structure, is a necessary criterion for crack propagation in a polymer network. Coarse-grained fracture simulations agree closely with the tearing energy trend observed experimentally, confirming that weak strand scissions dominate the failure until the strong strands approach percolation. The simulations further show that twice as many strands break in a mixture than in a pure network.
Collapse
Affiliation(s)
- Haley K Beech
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Shu Wang
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Devosmita Sen
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Dechen Rota
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Tatiana B Kouznetsova
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Akash Arora
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Michael Rubinstein
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
- Departments of Mechanical Engineering and Materials Sciences, Biomedical Engineering, and Physics, Duke University, Durham, North Carolina 27708, United States
| | - Stephen L Craig
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Bradley D Olsen
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
6
|
Wang S, Hu Y, Kouznetsova TB, Sapir L, Chen D, Herzog-Arbeitman A, Johnson JA, Rubinstein M, Craig SL. Facile mechanochemical cycloreversion of polymer cross-linkers enhances tear resistance. Science 2023; 380:1248-1252. [PMID: 37347867 DOI: 10.1126/science.adg3229] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 05/16/2023] [Indexed: 06/24/2023]
Abstract
The mechanical properties of covalent polymer networks often arise from the permanent end-linking or cross-linking of polymer strands, and molecular linkers that break more easily would likely produce materials that require less energy to tear. We report that cyclobutane-based mechanophore cross-linkers that break through force-triggered cycloreversion lead to networks that are up to nine times as tough as conventional analogs. The response is attributed to a combination of long, strong primary polymer strands and cross-linker scission forces that are approximately fivefold smaller than control cross-linkers at the same timescales. The enhanced toughness comes without the hysteresis associated with noncovalent cross-linking, and it is observed in two different acrylate elastomers, in fatigue as well as constant displacement rate tension, and in a gel as well as elastomers.
Collapse
Affiliation(s)
- Shu Wang
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Yixin Hu
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Tatiana B Kouznetsova
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Liel Sapir
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA
| | - Danyang Chen
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA
| | - Abraham Herzog-Arbeitman
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Department of Chemistry, Massachusetts Institute of Technology (MIT), Boston, MA, USA
| | - Jeremiah A Johnson
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Department of Chemistry, Massachusetts Institute of Technology (MIT), Boston, MA, USA
| | - Michael Rubinstein
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Department of Chemistry, Duke University, Durham, NC, USA
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA
- Departments of Biomedical Engineering and Physics, Duke University, Durham, NC, USA
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo 001-0021, Japan
| | - Stephen L Craig
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
- Department of Chemistry, Duke University, Durham, NC, USA
| |
Collapse
|
7
|
Wakefield H, Kevlishvili I, Wentz KE, Yao Y, Kouznetsova TB, Melvin SJ, Ambrosius EG, Herzog-Arbeitman A, Siegler MA, Johnson JA, Craig SL, Kulik HJ, Klausen RS. Synthesis and Ring-Opening Metathesis Polymerization of a Strained trans-Silacycloheptene and Single-Molecule Mechanics of Its Polymer. J Am Chem Soc 2023; 145:10187-10196. [PMID: 37017452 DOI: 10.1021/jacs.3c01004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
The cis- and trans-isomers of a silacycloheptene were selectively synthesized by the alkylation of a silyl dianion, a novel approach to strained cycloalkenes. The trans-silacycloheptene (trans-SiCH) was significantly more strained than the cis isomer, as predicted by quantum chemical calculations and confirmed by crystallographic signatures of a twisted alkene. Each isomer exhibited distinct reactivity toward ring-opening metathesis polymerization (ROMP), where only trans-SiCH afforded high-molar-mass polymer under enthalpy-driven ROMP. Hypothesizing that the introduction of silicon might result in increased molecular compliance at large extensions, we compared poly(trans-SiCH) to organic polymers by single-molecule force spectroscopy (SMFS). Force-extension curves from SMFS showed that poly(trans-SiCH) is more easily overstretched than two carbon-based analogues, polycyclooctene and polybutadiene, with stretching constants that agree well with the results of computational simulations.
Collapse
Affiliation(s)
- Herbert Wakefield
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ilia Kevlishvili
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kelsie E Wentz
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Yunxin Yao
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Sophia J Melvin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Em G Ambrosius
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Abraham Herzog-Arbeitman
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeremiah A Johnson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Rebekka S Klausen
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| |
Collapse
|
8
|
Wang J, Kouznetsova TB, Xia J, Ángeles FJ, de la Cruz MO, Craig SL. A polyelectrolyte handle for single‐molecule force spectroscopy. Journal of Polymer Science 2023. [DOI: 10.1002/pol.20230051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Affiliation(s)
- Junpeng Wang
- Department of Chemistry Duke University Durham North Carolina USA
| | | | - Jianshe Xia
- Department of Materials Science and Engineering Northwestern University Evanston Illinois USA
| | - Felipe Jiménez Ángeles
- Department of Materials Science and Engineering Northwestern University Evanston Illinois USA
| | | | - Stephen L. Craig
- Department of Chemistry Duke University Durham North Carolina USA
| |
Collapse
|
9
|
Ouchi T, Bowser BH, Kouznetsova TB, Zheng X, Craig SL. Strain-triggered acidification in a double-network hydrogel enabled by multi-functional transduction of molecular mechanochemistry. Mater Horiz 2023; 10:585-593. [PMID: 36484385 DOI: 10.1039/d2mh01105k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Recent work has demonstrated that force-triggered mechanochemical reactions within a polymeric material are capable of inducing measurable changes in macroscopic material properties, but examples of bulk property changes without irreversible changes in shape or structure are rare. Here, we report a double-network hydrogel that undergoes order-of-magnitude increases in acidity when strained, while recovering its initial shape after large deformation. The enabling mechanophore design is a 2-methoxy-gem-dichlorocyclopropane mechanoacid that is gated within a fused methyl methoxycyclobutene carboxylate mechanophore structure. This gated mechanoacid is incorporated via radical co-polymerization into linear and network polymers. Sonication experiments confirm the mechanical release of HCl, and single-molecule force spectroscopy reveals enhanced single-molecular toughness in the covalent strand. These mechanochemical functions are incorporated into a double-network hydrogel, leading to mechanically robust and thermally stable materials that undergo strain-triggered acid release. Both quasi-static stretching and high strain rate uniaxial compression result in substantial acidification of the hydrogel, from pH ∼ 7 to ∼5.
Collapse
Affiliation(s)
- Tetsu Ouchi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
| | - Brandon H Bowser
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
| | | | - Xujun Zheng
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
| |
Collapse
|
10
|
Wang L, Zheng X, Kouznetsova TB, Yen T, Ouchi T, Brown CL, Craig SL. Mechanochemistry of Cubane. J Am Chem Soc 2022; 144:22865-22869. [DOI: 10.1021/jacs.2c10878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Liqi Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Xujun Zheng
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | | | - Tiffany Yen
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tetsu Ouchi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Cameron L. Brown
- 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
| |
Collapse
|
11
|
Wang Z, Kouznetsova TB, Craig S. Pulling Outward but Reacting Inward: Mechanically Induced Symmetry-Allowed Reactions of cis- and trans-Diester-substituted Dichlorocyclopropanes. Synlett 2022. [DOI: 10.1055/a-1760-8817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The mechanically induced symmetry-allowed disrotatory ring-openings of cis- and trans- gem-dichlorocyclopropane (gDCC) diesters are demonstrated through sonication and single-molecule force spectroscopy (SMFS) studies. In contrast to the previously reported symmetry-forbidden conrotatory ring-opening of alkyl-tethered trans-gDCC, we show that the diester-tethered trans-gDCC primarily undergoes a symmetry-allowed disrotatory pathway even at the high forces (>2 nN) and short time scales (ms or less) of sonication and SMFS experiments. The quantitative force-rate data obtained from SMFS data is consistent with computational models of transition state geometry for the symmetry allowed process, and activation lengths of 1.41 ± 0.02 Å and 1.08 ± 0.03 Å are inferred for the cis-gDCC diester and trans-gDCC diester, respectively. The strong mechanochemical coupling in the trans-gDCC is notable, given that the directionality of the applied force may appear initially to oppose the disrotatory motion associated with the reaction. The stereochemical perturbations of mechanical coupling created by the ester attachments reinforce the complexity that is possible in covalent polymer mechanochemistry and illustrate the breadth of reactivity outcomes that are available through judicious mechanophore design.
Collapse
Affiliation(s)
- Zi Wang
- Chemistry, Duke University, Durham, United States
| | | | | |
Collapse
|
12
|
Wang Z, Zheng X, Ouchi T, Kouznetsova TB, Beech HK, Av-Ron S, Matsuda T, Bowser BH, Wang S, Johnson JA, Kalow JA, Olsen BD, Gong JP, Rubinstein M, Craig SL. Toughening hydrogels through force-triggered chemical reactions that lengthen polymer strands. Science 2021; 374:193-196. [PMID: 34618576 DOI: 10.1126/science.abg2689] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Zi Wang
- Department of Chemistry, Duke University, Durham, NC, USA.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
| | - Xujun Zheng
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Tetsu Ouchi
- Department of Chemistry, Duke University, Durham, NC, USA.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, NC, USA.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
| | - Haley K Beech
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA.,Department of Chemical Engineering, Massachussetts Institute of Technology (MIT), Boston, MA, USA
| | - Sarah Av-Ron
- Department of Chemical Engineering, Massachussetts Institute of Technology (MIT), Boston, MA, USA
| | - Takahiro Matsuda
- Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan
| | - Brandon H Bowser
- Department of Chemistry, Duke University, Durham, NC, USA.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
| | - Shu Wang
- Department of Chemistry, Duke University, Durham, NC, USA.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA
| | - Jeremiah A Johnson
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA.,Department of Chemistry, MIT, Boston, MA, USA
| | - Julia A Kalow
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA.,Department of Chemistry, Northwestern University, Evanston, IL, USA
| | - Bradley D Olsen
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA.,Department of Chemical Engineering, Massachussetts Institute of Technology (MIT), Boston, MA, USA
| | - Jian Ping Gong
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA.,Faculty of Advanced Life Science, Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan.,Soft Matter GI-CoRE, Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan.,Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan
| | - Michael Rubinstein
- Department of Chemistry, Duke University, Durham, NC, USA.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA.,Soft Matter GI-CoRE, Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan.,Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan.,Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA.,Department of Physics, Duke University, Durham, NC, USA
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, NC, USA.,NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, NC, USA.,Soft Matter GI-CoRE, Hokkaido University, N21W11, Kita-ku, Sapporo 001-0021, Japan
| |
Collapse
|
13
|
Horst M, Yang J, Meisner J, Kouznetsova TB, Martínez TJ, Craig SL, Xia Y. Understanding the Mechanochemistry of Ladder-Type Cyclobutane Mechanophores by Single Molecule Force Spectroscopy. J Am Chem Soc 2021; 143:12328-12334. [PMID: 34310875 DOI: 10.1021/jacs.1c05857] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have recently reported a series of ladder-type cyclobutane mechanophores, polymers of which can transform from nonconjugated structures to conjugated structures and change many properties at once. These multicyclic mechanophores, namely, exo-ladderane/ene, endo-benzoladderene, and exo-bicyclohexene-peri-naphthalene, have different ring structures fused to the first cyclobutane, significantly different free energy changes for ring-opening, and different stereochemistry. To better understand their mechanochemistry, we used single molecule force spectroscopy (SMFS) to characterize their force-extension behavior and measure the threshold forces. The threshold forces correlate with the activation energy of the first bond, but not with the strain of the fused rings distal to the polymer main chain, suggesting that the activation of these ladder-type mechanophores occurs with similar early transition states, which is supported by force-modified potential energy surface calculations. We further determined the stereochemistry of the mechanically generated dienes and observed significant and variable contour length elongation for these mechanophores both experimentally and computationally. The fundamental understanding of ladder-type mechanophores will facilitate future design of multicyclic mechanophores with amplified force-response and their applications as mechanically responsive materials.
Collapse
Affiliation(s)
- Matías Horst
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jinghui Yang
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jan Meisner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Todd J Martínez
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Yan Xia
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
14
|
Bowser BH, Wang S, Kouznetsova TB, Beech HK, Olsen BD, Rubinstein M, Craig SL. Single-Event Spectroscopy and Unravelling Kinetics of Covalent Domains Based on Cyclobutane Mechanophores. J Am Chem Soc 2021; 143:5269-5276. [PMID: 33783187 DOI: 10.1021/jacs.1c02149] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mechanochemical reactions that lead to an increase in polymer contour length have the potential to serve as covalent synthetic mimics of the mechanical unfolding of noncovalent "stored length" domains in structural proteins. Here we report the force-dependent kinetics of stored length release in a family of covalent domain polymers based on cis-1,2-substituted cyclobutane mechanophores. The stored length is determined by the size (n) of a fused ring in an [n.2.0] bicyclic architecture, and it can be made sufficiently large (>3 nm per event) that individual unravelling events are resolved in both constant-velocity and constant-force single-molecule force spectroscopy (SMFS) experiments. Replacing a methylene in the pulling attachment with a phenyl group drops the force necessary to achieve rate constants of 1 s-1 from ca. 1970 pN (dialkyl handles) to 630 pN (diaryl handles), and the substituent effect is attributed to a combination of electronic stabilization and mechanical leverage effects. In contrast, the kinetics are negligibly perturbed by changes in the amount of stored length. The independent control of unravelling force and extension holds promise as a probe of molecular behavior in polymer networks and for optimizing the behaviors of materials made from covalent domain polymers.
Collapse
Affiliation(s)
- Brandon H Bowser
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States.,Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Shu Wang
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States.,Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tatiana B Kouznetsova
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States.,Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Haley K Beech
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States.,Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Bradley D Olsen
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States.,Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Michael Rubinstein
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States.,Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,Departments of Physics, Mechanical Engineering and Materials Science, and Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States.,World Premier Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan
| | - Stephen L Craig
- NSF Center for the Chemistry of Molecularly Optimized Networks, Duke University, Durham, North Carolina 27708, United States.,Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| |
Collapse
|
15
|
Wang S, Beech HK, Bowser BH, Kouznetsova TB, Olsen BD, Rubinstein M, Craig SL. Mechanism Dictates Mechanics: A Molecular Substituent Effect in the Macroscopic Fracture of a Covalent Polymer Network. J Am Chem Soc 2021; 143:3714-3718. [PMID: 33651599 DOI: 10.1021/jacs.1c00265] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The fracture of rubbery polymer networks involves a series of molecular events, beginning with conformational changes along the polymer backbone and culminating with a chain scission reaction. Here, we report covalent polymer gels in which the macroscopic fracture "reaction" is controlled by mechanophores embedded within mechanically active network strands. We synthesized poly(ethylene glycol) (PEG) gels through the end-linking of azide-terminated tetra-arm PEG (Mn = 5 kDa) with bis-alkyne linkers. Networks were formed under identical conditions, except that the bis-alkyne was varied to include either a cis-diaryl (1) or cis-dialkyl (2) linked cyclobutane mechanophore that acts as a mechanochemical "weak link" through a force-coupled cycloreversion. A control network featuring a bis-alkyne without cyclobutane (3) was also synthesized. The networks show the same linear elasticity (G' = 23-24 kPa, 0.1-100 Hz) and equilibrium mass swelling ratios (Q = 10-11 in tetrahydrofuran), but they exhibit tearing energies that span a factor of 8 (3.4 J, 10.6, and 27.1 J·m-2 for networks with 1, 2, and 3, respectively). The difference in fracture energy is well-aligned with the force-coupled scission kinetics of the mechanophores observed in single-molecule force spectroscopy experiments, implicating local resonance stabilization of a diradical transition state in the cycloreversion of 1 as a key determinant of the relative ease with which its network is torn. The connection between macroscopic fracture and a small-molecule reaction mechanism suggests opportunities for molecular understanding and optimization of polymer network behavior.
Collapse
Affiliation(s)
| | - Haley K Beech
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | | | - Bradley D Olsen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | | |
Collapse
|
16
|
Brown CL, Bowser BH, Meisner J, Kouznetsova TB, Seritan S, Martinez TJ, Craig SL. Substituent Effects in Mechanochemical Allowed and Forbidden Cyclobutene Ring-Opening Reactions. J Am Chem Soc 2021; 143:3846-3855. [PMID: 33667078 DOI: 10.1021/jacs.0c12088] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Woodward and Hoffman once jested that a very powerful Maxwell demon could seize a molecule of cyclobutene at its methylene groups and tear it open in a disrotatory fashion to obtain butadiene (Woodward, R. B.; Hoffmann, R. The Conservation of Orbital Symmetry. Angew. Chem., Int. Ed. 1969, 8, 781-853). Nearly 40 years later, that demon was discovered, and the field of covalent polymer mechanochemistry was born. In the decade since our demon was befriended, many fundamental investigations have been undertaken to build up our understanding of force-modified pathways for electrocyclic ring-opening reactions. Here, we seek to extend that fundamental understanding by exploring substituent effects in allowed and forbidden ring-opening reactions of cyclobutene (CBE) and benzocyclobutene (BCB) using a combination of single-molecule force spectroscopy (SMFS) and computation. We show that, while the forbidden ring-opening of cis-BCB occurs at a lower force than the allowed ring-opening of trans-BCB on the time scale of the SMFS experiment, the opposite is true for cis- and trans-CBE. Such a reactivity flip is explained through computational analysis and discussion of the so-called allowed/forbidden gap.
Collapse
Affiliation(s)
- Cameron L Brown
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Brandon H Bowser
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Jan Meisner
- Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Stefan Seritan
- Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Todd J Martinez
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| |
Collapse
|
17
|
Razgoniaev AO, Glasstetter LM, Kouznetsova TB, Hall KC, Horst M, Craig SL, Franz KJ. Single-Molecule Activation and Quantification of Mechanically Triggered Palladium-Carbene Bond Dissociation. J Am Chem Soc 2021; 143:1784-1789. [PMID: 33480680 DOI: 10.1021/jacs.0c13219] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Metal-complexed N-heterocyclic carbene (NHC) mechanophores are latent reactants and catalysts for a range of mechanically driven chemical responses, but mechanochemical scission of the metal-NHC bond has not been experimentally characterized. Here we report the single-molecule force spectroscopy of ligand dissociation from a pincer NHC-pyridine-NHC Pd(II) complex. The force-coupled rate constant for ligand dissociation reaches 50 s-1 at forces of approximately 930 pN. Experimental and computational observations support a dissociative, rather than associative, mechanism of ligand displacement, with rate-limiting scission of the Pd-NHC bond followed by rapid dissociation of the pyridine moiety from Pd.
Collapse
Affiliation(s)
- Anton O Razgoniaev
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Logan M Glasstetter
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Kacey C Hall
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Matias Horst
- 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
| | - Katherine J Franz
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| |
Collapse
|
18
|
Zhang Y, Wang Z, Kouznetsova TB, Sha Y, Xu E, Shannahan L, Fermen-Coker M, Lin Y, Tang C, Craig SL. Distal conformational locks on ferrocene mechanophores guide reaction pathways for increased mechanochemical reactivity. Nat Chem 2020; 13:56-62. [DOI: 10.1038/s41557-020-00600-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 11/03/2020] [Indexed: 12/14/2022]
|
19
|
Lin Y, Kouznetsova TB, Chang CC, Craig SL. Enhanced polymer mechanical degradation through mechanochemically unveiled lactonization. Nat Commun 2020; 11:4987. [PMID: 33020488 PMCID: PMC7536186 DOI: 10.1038/s41467-020-18809-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 09/10/2020] [Indexed: 12/11/2022] Open
Abstract
The mechanical degradation of polymers is typically limited to a single chain scission per triggering chain stretching event, and the loss of stress transfer that results from the scission limits the extent of degradation that can be achieved. Here, we report that the mechanically triggered ring-opening of a [4.2.0]bicyclooctene (BCOE) mechanophore sets up a delayed, force-free cascade lactonization that results in chain scission. Delayed chain scission allows many eventual scission events to be initiated within a single polymer chain. Ultrasonication of a 120 kDa BCOE copolymer mechanically remodels the polymer backbone, and subsequent lactonization slowly (~days) degrades the molecular weight to 4.4 kDa, > 10× smaller than control polymers in which lactonization is blocked. The force-coupled kinetics of ring-opening are probed by single molecule force spectroscopy, and mechanical degradation in the bulk is demonstrated. Delayed scission offers a strategy to enhanced mechanical degradation and programmed obsolescence in structural polymeric materials.
Collapse
Affiliation(s)
- Yangju Lin
- Department of Chemistry, Duke University, Durham, NC, 27708, USA.
| | | | - Chia-Chih Chang
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, NC, 27708, USA.
| |
Collapse
|
20
|
Abstract
Degradable polymers are desirable for the replacement of conventional organic polymers that persist in the environment, but they often suffer from the unintentional scission of the degradable functionalities on the polymer backbone, which diminishes polymer properties during storage and regular use. Herein, we report a strategy that combats unintended degradation in polymers by combining two common degradation stimuli-mechanical and acid triggers-in an "AND gate" fashion. A cyclobutane (CB) mechanophore is used as a mechanical gate to regulate an acid-sensitive ketal that has been widely employed in acid degradable polymers. This gated ketal is further incorporated into the polymer backbone. In the presence of an acid trigger alone, the pristine polymer retains its backbone integrity, and delivering high mechanical forces alone by ultrasonication degrades the polymer to an apparent limiting molecular weight of 28 kDa. The sequential treatment of ultrasonication followed by acid, however, leads to a further 11-fold decrease in molecular weight to 2.5 kDa. Experimental and computational evidence further indicate that the ungated ketal possesses mechanical strength that is commensurate with the conventional polymer backbones. Single molecule force spectroscopy (SMFS) reveals that the force necessary to activate the CB molecular gate on the time scale of 100 ms is approximately 2 nN.
Collapse
Affiliation(s)
- Yangju Lin
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States
| | - Tatiana B Kouznetsova
- 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
| |
Collapse
|
21
|
Lin Y, Kouznetsova TB, Craig SL. A Latent Mechanoacid for Time-Stamped Mechanochromism and Chemical Signaling in Polymeric Materials. J Am Chem Soc 2019; 142:99-103. [DOI: 10.1021/jacs.9b12861] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Yangju Lin
- 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
| |
Collapse
|
22
|
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: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
23
|
Wang J, Kouznetsova TB, Craig SL. Single-Molecule Observation of a Mechanically Activated Cis-to-Trans Cyclopropane Isomerization. J Am Chem Soc 2016; 138:10410-2. [DOI: 10.1021/jacs.6b06452] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Junpeng 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
| |
Collapse
|
24
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
25
|
Wang J, Ong MT, Kouznetsova TB, Lenhardt JM, Martínez TJ, Craig SL. Catch and Release: Orbital Symmetry Guided Reaction Dynamics from a Freed “Tension Trapped Transition State”. J Org Chem 2015; 80:11773-8. [DOI: 10.1021/acs.joc.5b01493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Junpeng Wang
- Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Mitchell T. Ong
- Materials
Science Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | | | - Jeremy M. Lenhardt
- Materials
Science Division, Lawrence Livermore National Laboratory, Livermore, California 94550, 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
| |
Collapse
|
26
|
Lenhardt JM, Black Ramirez AL, Lee B, Kouznetsova TB, Craig SL. Mechanistic Insights into the Sonochemical Activation of Multimechanophore Cyclopropanated Polybutadiene Polymers. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01677] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jeremy M. Lenhardt
- Materials Science Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | | | - Bobin Lee
- Department of Chemistry, Duke University, Durham, North Carolina 27708-0346, United States
| | - Tatiana B. Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708-0346, United States
| | - Stephen L. Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708-0346, United States
| |
Collapse
|
27
|
Wang J, Kouznetsova TB, Craig SL. Reactivity and Mechanism of a Mechanically Activated anti-Woodward–Hoffmann–DePuy Reaction. J Am Chem Soc 2015; 137:11554-7. [DOI: 10.1021/jacs.5b06168] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Junpeng 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
| |
Collapse
|
28
|
Wang J, Kouznetsova TB, Niu Z, Rheingold AL, Craig SL. Accelerating a Mechanically Driven anti-Woodward–Hoffmann Ring Opening with a Polymer Lever Arm Effect. J Org Chem 2015; 80:11895-8. [DOI: 10.1021/acs.joc.5b01465] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junpeng Wang
- Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | | | - Zhenbin Niu
- Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Arnold L. Rheingold
- Department
of Chemistry, University of California, La Jolla, California 92093, United States
| | - Stephen L. Craig
- Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
| |
Collapse
|
29
|
Affiliation(s)
- Gregory R. Gossweiler
- 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
| |
Collapse
|
30
|
Kean ZS, Gossweiler GR, Kouznetsova TB, Hewage GB, Craig SL. A coumarin dimer probe of mechanochemical scission efficiency in the sonochemical activation of chain-centered mechanophore polymers. Chem Commun (Camb) 2015; 51:9157-60. [DOI: 10.1039/c5cc01836f] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A coumarin dimer mechanophore is used to probe the effect of polymer size and polydispersity on mechanochemical activation.
Collapse
Affiliation(s)
- Zachary S. Kean
- Department of Chemistry
- Duke University
- French Family Science Center
- Durham
- USA
| | | | | | - Gihan B. Hewage
- Department of Chemistry
- Duke University
- French Family Science Center
- Durham
- USA
| | - Stephen L. Craig
- Department of Chemistry
- Duke University
- French Family Science Center
- Durham
- USA
| |
Collapse
|
31
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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
| |
Collapse
|