Review
Chemistry, Inorganic & Nuclear
Ayumu Karimata, Julia R. Khusnutdinova
Summary: The development of mechanoresponsive polymers, where changes at the molecular level have macrolevel effects, is an attractive area of research. The use of organic mechanophores has been dominant, but recently there has been a focus on organotransition metal complexes as new mechanophores. This article summarizes recent developments in the use of copper-N-heterocyclic carbene (NHC) complexes with dynamic pyridinophane ligands as new organometallic mechanophores.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Hanna Traeger, Yoshimitsu Sagara, Derek J. Kiebala, Stephen Schrettl, Christoph Weder
Summary: A supramolecular mechanophore capable of indicating deformation through fluorescence color change when integrated into polymers was reported. The mechanophore exhibited an instant response with a linear correlation to applied strain, offering advantages over intermolecular dye aggregates. The experiments showed that looped mechanophores displaying intramolecular excimer formation provide a more pronounced and concentration-independent optical change, directly signaling mechanical processes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Davide Campagna, Robert Goestl
Summary: This study reports a mechanochemical protecting group for secondary amines that can be activated in polymers through force-induced reactions. The research demonstrates that this protecting group can produce free amines in polymers through bond scission, similar to its photochemical counterpart. Additionally, the protecting group is applied in a force-activated organocatalytic reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Hajime Sugita, Yi Lu, Daisuke Aoki, Hideyuki Otsuka, Koichiro Mikami
Summary: In this study, the synthesis and characterization of two series of arylfluorene-based mechanophores were reported. Density functional theory (DFT) calculations revealed the importance of thermodynamic stability and oxygen tolerance for the functions and applicability of these materials. Furthermore, the mechanochromism of a polymer containing one of the mechanophores was demonstrated through ball-milling.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Hajime Sugita, Yi Lu, Daisuke Aoki, Hideyuki Otsuka, Koichiro Mikami
Summary: Radical-type mechanophores (RMs) can undergo homolytic cleavage of their central C-C bonds upon exposure to mechanical forces, which affords radical species. Understanding the characteristics of these radical species allows bespoke mechanoresponsive materials to be designed and developed. In this paper, the synthesis and characterization of arylfluorene-based RM derivatives, and the importance of thermodynamic stability and oxygen tolerance for their functions and applicability, are reported. Furthermore, the mechanochromism of a BTAF-centered polymer synthesized by ATRP was demonstrated.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Polymer Science
Kuniaki Ishizuki, Daisuke Aoki, Hideyuki Otsuka
Summary: Mechanochromic polymers can be used as sensors to detect stress and damage in polymeric materials by visualizing mechanical stimuli through color changes. By mixing white powders of two mechanochromic polystyrene samples with different mechanochromophores, the duration of mechanical stimulation can be detected through multicolor mechanochromism, allowing for distinguishing between short and long exposure to grinding.
MACROMOLECULAR RAPID COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Huan Hu, Xin Cheng, Zhimin Ma, Rint P. Sijbesma, Zhiyong Ma
Summary: This study reports the development of a mechanochromic mechanophore based on excited-state intramolecular proton transfer (ESIPT) for real-time strain sensing in polyurethane films. The mechanophore exhibited high sensitivity and excellent reversibility to stress, and the mechanochromism was attributed to chain-transduced force. Density function theory (DFT) calculation was performed to analyze the force-tuned ESIPT process. This research lays the foundation for practical applications in real-time stress/strain sensing.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Ankita Das, Ayan Datta
Summary: Mechanical force can release small molecules from macromolecular carriers in a predictable and precise manner. Using mechanochemical simulations, this study demonstrates that norborn-2-en-7-one (NEO) and its derivatives can selectively release CO, N-2, and SO2 to generate two distinct products A and B. The regioselectivity in the pulling points enables the exclusive formation of either A or B. Through changing the rigidity of the NEO scaffold and tuning the pulling groups, control over the selective formation of B is achieved. The diradical intermediate formed during the conversion of I to A is predicted to be persistent for approximately 150 fs. Structural design plays a crucial role in balancing the mechanochmeical rigidity and lability.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Gianmarco Pisano, Catherine S. J. Cazin
Summary: A user-friendly and highly efficient mechanochemical strategy for the synthesis of well-defined, catalytically relevant N-heterocyclic carbene-metal complexes is reported. The protocol yields good to excellent results and minimizes solvent usage by only using environmentally benign solvents in the purification step.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Raphael Hertel, Wafa Maftuhin, Michael Walter, Michael Sommer
Summary: In this study, we used a series of thiophene-flanked quinoxalines as molecular torsional springs for force sensing in bulk polymers at room temperature. Through detailed spectroscopy and calculations, we identified the thiophene ring flip as the major part of the overall mechanochromic response. The thiophene ring flip requires much smaller forces than planarization of the DAD spring, allowing for sensing of tiny forces and expanding the sensitivity and force range of conformational mechanochromophores.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Polymer Science
Xiaoying Wang, Yifeng Cao, Yanling Peng, Lewen Wang, Wangmeng Hou, Yecheng Zhou, Yi Shi, Huahua Huang, Yongming Chen, Yuanchao Li
Summary: This novel mechanophore undergoes a chemical reaction upon mechanical activation, resulting in the generation of two new substances with different fluorescent colors. It also exhibits sensitivity to solvents, enabling dual-color mechanochromism.
Article
Chemistry, Organic
Zhen Li, Pengju Ji, Jin-Pei Cheng
Summary: A Brønsted basicity scale was established for nine representative N-heterocyclic olefins (NHOs) using an UV-visible spectroscopic method. The unsaturated NHOs were found to have stronger basicities compared to their N-heterocyclic carbene (NHC) analogues, while the basicities of the saturated NHOs were weaker. The nucleophilicity of the NHOs was also stronger than commonly used Lewis bases but weaker than their NHC analogues.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Ludwig Zapf, Udo Radius, Maik Finze
Summary: The paper describes the synthesis of 1,3-bis(tricyanoborane)imidazolate anion and its derivatives, including a novel dianionic N-heterocyclic carbene. These compounds exhibit unique electronic and steric properties, making them promising ligands and building blocks for coordination chemistry.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Junbeom Park, Jaelim Kim, Gu Yoon Jeong, Youngsuk Kim, Eunsung Lee
Summary: This study investigates the electron and proton transfer chemistry of N-heterocyclic carbene nitric oxide radical compounds and prepares a variety of nitrosyl derivatives. The reactions of these derivatives resemble those of transition metal nitrosyl complexes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Biochemical Research Methods
Fady Nahra, Nikolaos Tzouras, Alba Collado, Steven P. Nolan
Summary: N-heterocyclic carbene gold(I) chloride and hydroxide complexes are commonly used as synthetic reagents and efficient catalysts. This study describes a straightforward and practical method for synthesizing mononuclear gold complexes with high yields, as well as the synthesis of a mononuclear gold(I) hydroxide complex and an improved synthesis method for a dinuclear gold(I) hydroxide complex. This methodology offers advantages such as the use of sustainable reaction solvents and commercially available starting materials.
Article
Polymer Science
Michael B. Larsen, Shannon E. Herzog, Helena C. Quitter, Marc A. Hillmyer
Article
Chemistry, Multidisciplinary
Michael B. Larsen, Shao-Jie Wang, Marc A. Hillmyer
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2018)
Article
Chemistry, Multidisciplinary
Hang Shen, Xiao Xiao, Moriana K. Haj, Patrick H. Willoughby, Thomas R. Hoye
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2018)
Article
Chemistry, Organic
Hang Shen, Xiao Xiao, Thomas R. Hoye
Article
Chemistry, Physical
Bryce M. Lipinski, Katherine L. Walker, Naomi E. Clayman, Lilliana S. Morris, Timothy M. E. Jugovic, Allison G. Roessler, Yutan D. Y. L. Getzler, Samantha N. MacMillan, Richard N. Zare, Paul M. Zimmerman, Robert M. Waymouth, Geoffrey W. Coates
Article
Polymer Science
Alberto J. Melchor Banales, Michael B. Larsen
Review
Nanoscience & Nanotechnology
Maroun Abi Ghanem, Amrita Basu, Reza Behrou, Nicholas Boechler, Andrew J. Boydston, Stephen L. Craig, Yangju Lin, Brock E. Lynde, Alshakim Nelson, Hang Shen, Duane W. Storti
Summary: Polymer mechanochemistry involves converting mechanical forces in materials to chemical reactions through the response of functional groups known as mechanophores. This technology has applications in materials science, polymer physics, and additive manufacturing. The historical development of using mechanical force to chemically transform polymers spans decades, leading to a range of engineered molecular responses that impact optical, mechanical, electronic, and thermal properties.
NATURE REVIEWS MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Xuejin Yang, Sean R. Gitter, Allison G. Roessler, Paul M. Zimmerman, Andrew J. Boydston
Summary: Research has found a simple method to control alkene stereochemistry in photoredox mediated metal-free ring-opening metathesis polymerization. Ion-pairing, initiator sterics, and solvation effects each have a profound impact on polynorbornene's stereochemistry. By adjusting reaction conditions, it is possible to control the cis or trans alkene content of PNB.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Chengqiang Ding, Yuhan Yan, Yuhao Peng, Danming Wu, Hang Shen, Jiandong Zhang, Zhao Wang, Zhengbiao Zhang
Summary: In this study, a well-controlled piezoelectrically mediated reversible addition-fragmentation chain-transfer polymerization (piezoRAFT) was successfully conducted using piezoelectric ZnO nanoparticles as the mechanochemical transducer under ultrasonic agitation. The resulting polymer exhibited high end-group fidelity, low dispersity, and capacity for chain extension. The generation of alkyl radicals through electron transfer process from piezoelectric nanoparticles to alkyl bromide was confirmed by various characterization techniques.
Article
Multidisciplinary Sciences
Colin D. Marquis, Lindze M. McCarley, Amy L. Pollock, Acamaro S. Cutcher, Max T. Cannella, Tierra L. Smith, Michael B. Larsen, Brandon M. Peden, Brad L. Johnson, Janelle M. Leger
Summary: This paper demonstrates a technique for direct reflectance excitation and detection of forbidden guided-wave plasmon polariton modes (GW-PPMs). By replacing the air gap used in traditional Otto ATR with a low refractive index polymer coupling layer, GW-PPMs can be excited. This method has the potential to significantly enhance performance in many critical technologies.
Article
Chemistry, Organic
Venecia Ramirez, Evan B. Van Pelt, Reeth K. Pooni, Alberto J. Melchor Banales, Michael B. Larsen
Summary: This study investigates the thermal guanidine metathesis (TGM) reaction, which involves a reversible transformation of N-substituents in the guanidine functional group. The results show that steric congestion and the nature of N-substitution play crucial roles in determining the equilibrium composition and reaction kinetics. It is also demonstrated that TGM occurs under thermodynamic control and proceeds via a dissociative mechanism.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Hang Shen, Yunzheng Cao, Miaojiang Lv, Qinxin Sheng, Zhengbiao Zhang
Summary: The field of force-induced release of small cargoes within polymeric materials has grown rapidly in the past decade, achieving diversified functional materials and investigating force-coupled reactivity of mechanophores. By discussing different types of mechanophores and their mechanochemical reactions, it is possible to release acids, gases, fluorophores, drugs, iron ions, and more. The challenges and future targets in this growing field are also discussed.
CHEMICAL COMMUNICATIONS
(2022)
