Article
Chemistry, Multidisciplinary
Phong K. Quach, Jesse H. Hsu, Ivan Keresztes, Brett P. Fors, Tristan H. Lambert
Summary: The ring-opening metathesis polymerization of cyclopropenes using hydrazonium initiators was investigated. The initiators, formed by condensing 2,3-diazabicyclo[2.2.2]octane and an aldehyde, polymerize cyclopropene monomers through a sequence of [3+2] cycloaddition and cycloreversion reactions. The study showed that the monomer to initiator ratio had a positive correlation with the degree of polymerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Biochemistry & Molecular Biology
Ervin Kovacs, Bence Balterer, Nguyen Anh Duc, Gyorgyi Szarka, Michael C. Owen, Attila Domjan, Bela Ivan
Summary: A large number of organic solvents contaminate the environment on a daily basis worldwide. This study demonstrates that benzotrifluoride can be used as a suitable solvent for olefin metathesis reactions, providing high yields and similar or even higher reaction rates compared to dichloromethane.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Polymer Science
Yujin Cha, JiHyeon Hwang, Luis Ramos, Huina Lin, Tianyu Zhu, Chuanbing Tang
Summary: The synthesis of cyclic cobaltocenium and its application in the synthesis of high-performance copolymers have been reported.
Article
Materials Science, Multidisciplinary
Mohamed Naguib, Atteya Rashed, Daniel J. Keddie
Summary: Novel bio-derivable tricyclic oxanorbornene polymers have been prepared via ROMP using secondary furfurylamine and maleic anhydride derived monomers. These polymers exhibit thermal reversible crosslinking and self-healing properties, showing potential for various applications in the future.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
Samuel C. Leguizamon, Kenneth Lyons, Nicolas T. Monk, Madison T. Hochrein, Brad H. Jones, Jeffrey C. Foster
Summary: Thermoset materials, which have excellent thermal and mechanical properties, are widely used in high-performance plastics. However, their lack of degradability has been a problem. This study demonstrates for the first time that an industrial thermoset material, polydicyclopentadiene, can be additively manufactured with degradable linkages using a photochemical approach. The resulting objects can be rapidly degraded to soluble byproducts through acid treatment. This work highlights the potential of ring-opening metathesis polymerization chemistry for creating degradable materials suitable for advanced manufacturing processes.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Chemical
Avery J. Boyer, Ngon T. Tran, Daniel B. Knorr
Summary: This study evaluated the performance of poly(dicyclopentadiene) (pDCPD) for structural adhesive applications through single lap shear experiments. The choice of silane and monomer-to-catalyst ratio were found to significantly affect the adhesive shear properties of pDCPD. The oxidation of pDCPD and the topology of the bulk polymer showed insignificant effects on adhesive properties in the absence of exposed oxygen-rich surfaces. pDCPD-based adhesives demonstrated comparable lap shear properties to a well-studied model thermoset epoxy.
JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Dmitry S. Belov, Logesh Mathivathanan, Melanie J. Beazley, William Blake Martin, Konstantin V. Bukhryakov
Summary: The study explores the capability of an iron-based catalyst in performing ring-opening metathesis polymerization of olefins, demonstrating that the use of in situ prepared heteroleptic iron catalysts significantly enhances polymerization rate and selectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Chemistry, Applied
Nina Guy, Olivia Giani, Sebastien Blanquer, Julien Pinaud, Jean-Jacques Robin
Summary: Photopolymerization is gaining interest in both industrial and academic fields due to its high reaction kinetics, low emissions of organic solvents, and reduced shrinking stress. This method has mainly been developed for radical polymerization of vinyl monomers and to a lesser extent for ring-opening polymerization (ROP). With the emergence of new initiating systems, the photopolymerization of various cyclic monomers has expanded beyond epoxides, which were the first monomers polymerized by cationic ring-opening polymerization (CROP).
PROGRESS IN ORGANIC COATINGS
(2021)
Article
Polymer Science
Mohammad Yasir, Andreas F. M. Kilbinger
Summary: Norbornene and cyclohexene show different polymerization behaviors using Grubbs' catalysts due to their varying ring strain energy levels; a sequence-selective cascade polymerization of a monomer containing both rings resulted in polymers with moderate molecular weight dispersities and good control over molecular weight.
Article
Polymer Science
Huijie Yi, Jingjing Gao, Siyang Lin, Jiawei Ma, Jinbao Guo
Summary: Photoresponsive fluorescent liquid crystal polymers with excellent mechanical properties and controlled molecular alignment have been synthesized in this study. The highly polarized emission pattern and tunable photoluminescence of the polymer are achieved by photoinduced alignment and Z/E photoisomerization. This versatile polymer material shows great potential for information storage and encoding applications.
Article
Chemistry, Multidisciplinary
Giovanni Occhipinti, Daniel L. Nascimento, Marco Foscato, Deryn E. Fogg, Vidar R. Jensen
Summary: This study investigates the factors promoting or inhibiting β-H elimination in the metathesis of alcohols and styrene using silicon-cyclic (alkyl)(amino)carbene (CAAC) catalysts and N-heterocyclic carbene (NHC) catalysts. The results show that CAAC catalysts have a stronger trans effect, which inhibits β-H elimination. However, the strong trans effect of CAAC catalysts also accelerates other decomposition pathways of the catalyst.
Article
Polymer Science
Geonhui Park, Christopher W. Bielawski
Summary: The ring opening metathesis polymerization of cyclic allenes using Grubbs-type catalysts integrates allenes into the main chains of polymers, confirmed by various spectroscopic, chromatographic, and chemical techniques. Acyclic, 1,3-disubstituted allenes serve as chain transfer agents in the reactions, providing end-functionalized polymers and controlling molecular weights. The obtained polymers can be modified into silyl-containing derivatives through a hydrosilylation-based post-polymerization modification, with a proposed mechanism involving ruthenium vinylidene intermediates and selective chain transfer.
Article
Chemistry, Physical
Noy B. Nechmad, Keren Iudanov, Naziha Tarannam, Victoria Kobernik, Sebastian Kozuch, N. Gabriel Lemcoff
Summary: The ruthenium alkylidene-catalyzed ring-closing metathesis (RCM) of 5-membered rings is highly favored due to entropic and enthalpic contributions. However, the RCM of a hindered diene could only be achieved at high concentrations using a trifluoromethyl sulfur-chelated ruthenium benzylidene catalyst. The addition of ethyl acetate significantly enhanced the catalyst's activity.
Article
Polymer Science
Henry L. Cater, Iana Balynska, Marshall J. Allen, Benny D. Freeman, Zachariah A. Page
Summary: This paper presents a systematic study on ROMP with endo-norbornene monomers using stable chelated Ru-alkylidene initiators. The study shows that ROMP with endo-norbornene monomers is versatile and robust, providing access to polymers with excellent molecular weight control, low dispersities, good functional group tolerance, and high chain-end fidelity. The process is oxygen-tolerant and can be performed under ambient conditions, allowing for the synthesis of mechanically robust thermoplastics with high glass transition and decomposition temperatures.
Article
Polymer Science
Jian Chen, Tianchi Xu, Weiguang Zhao, Ling-Ling Ma, Dongzhong Chen, Yan-Qing Lu
Summary: The study presents the synthesis of two azobenzene side-chain liquid crystalline polynorbornenes with different molecular weights, demonstrating excellent photoisomerization and photoalignment properties for potential applications in liquid crystal photoalignment systems and photoresponsive devices.
Article
Chemistry, Multidisciplinary
Paul Zaby, Jan Blasius, Anna K. Mueller, Steven P. Nolan, Oldamur Holloczki
Summary: The formation mechanism of metal-N-heterocyclic carbene (NHC) complexes from imidazolium salts in the presence of weak bases was investigated through theoretical methods. Quantum chemical calculations revealed that both sodium acetate and trimethylamine facilitate complex formation. Molecular dynamics simulations showed that the ionic nature of the [AuCl2](-) and imidazolium ions, as well as the sodium acetate base, keep these species associated in the reaction mixture through ion pairing. The neutral amine, however, remains mostly separated from the other reaction partners, making it a significantly less effective base.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Editorial Material
Chemistry, Multidisciplinary
Paul Zaby, Jan Blasius, Anna K. K. Mueller, Steven P. P. Nolan, Oldamur Holloczki
Summary: In this issue, Oldamur Hollczki and co-workers from the Universities of Bonn, Ghent and Debrecen are featured on the cover. The image showcases the quest for an ionic base that can combine with the acidic proton of an imidazolium cation to form a carbene complex. For the full article, visit 10.1002/chem.202203636.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Jennifer Morvan, Dylan Bouetard, Lingyu Kong, Yajie Chou, Thomas Vives, Muriel Albalat, Thierry Roisnel, Christophe Crevisy, Paola Nava, Stephane Humbel, Nicolas Vanthuyne, Herve Clavier, Marc Mauduit
Summary: A set of 16 chiral ruthenium complexes with atropisomerically stable N-Heterocyclic Carbene (NHC) ligands were synthesized. Among them, (atrop)BIAN-NHC Ru-catalyst showed the highest activity (up to 97 : 3 enantiomeric ratio) in asymmetric ring-opening-cross metathesis (AROCM) and was further converted to a Z-selective catechodithiolate complex. This complex exhibited high efficiency in Z-selective AROCM of exo-norbornenes, producing trans-cyclopentanes with excellent Z-selectivity (>98%) and high enantioselectivity (up to 96.5 : 3.5 enantiomeric ratio).
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Sebastien G. Guillet, Ishfaq Ibni Hashim, Marek Belis, Kristof Van Hecke, Catherine S. J. Cazin, Steven. P. Nolan
Summary: A simple synthetic method for synthesizing various [Rh(acac)(CO)(NHC)] complexes is presented. In situ infrared monitoring provides valuable information on the reaction mechanism, including the identification of a crucial intermediate. Understanding the reaction mechanism has led to the discovery of novel pathways to commonly used congeners.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Sebastien G. Guillet, Aleksei A. Logvinov, Vladislav A. Voloshkin, Ekaterina A. Martynova, Steven P. Nolan
Summary: Researchers report a simple method for the synthesis of azetidines from 2-isoxasoline-3-carboxylates and alkenes, using [Au(cbz)(NHC)] complexes as photocatalysts. The reaction is applicable to a wide range of substrates. Mechanistic studies confirm the energy transfer pathway. This study further expands the potential application of gold catalysts in energy transfer chemistry and catalysis.
Article
Chemistry, Physical
Nikolaos V. Tzouras, Leandros P. Zorba, Entzy Kaplanai, Nikolaos Tsoureas, David J. Nelson, Steven P. Nolan, Georgios C. Vougioukalakis
Summary: Despite the usefulness of gold catalysis in organic synthesis, it often requires activators and/or additives to generate cationic forms of gold catalysts. In this study, hexafluoroisopropanol (HFIP) is found to be a simple tool for gold-catalyzed cycloisomerizations, eliminating the need for external activators. HFIP acts as both a solvent and an activator through dynamic activation of the Au-Cl bond via hydrogen bonding. This unique mode of catalysis enables efficient and scalable cyclization reactions without the use of complex ligand/catalyst designs or activators.
Article
Chemistry, Physical
Sylwia Ostrowska, Lorenzo Palio, Agnieszka Czapik, Subhrajyoti Bhandary, Marcin Kwit, Kristof Van Hecke, Steven P. Nolan
Summary: In this study, a synthetic protocol was developed to prepare palladacycle complexes using a mild base and environmentally friendly solvent, with a focus on complexes with backbone-substituted N-heterocyclic carbene ligands. The accessible complexes exhibited high catalytic activity in the Buchwald-Hartwig amination, with low catalyst loading and mild reaction conditions achieved in a green solvent.
Article
Biochemistry & Molecular Biology
Cleiment Gonnot, Mathieu Scalabrini, Benoit Roubinet, Ceilia Ziane, Fabien Boeda, David Deniaud, Ludovic Landemarre, Seibastien G. Gouin, Laurent Fontaine, Veironique Montembault
Summary: Well-defined, highly reactive poly(norbornenyl azlactone)s were synthesized by ring-opening metathesis polymerization (ROMP) of pure exo-norbornenyl azlactone with controlled length. Postpolymerization modification (PPM) strategy based on click aminolysis of azlactone side groups was employed to convert them into glycopolymers using pegylated mannoside, heptyl-mannoside, and pegylated glucoside. The resulting glycopolymers showed strong binding inhibition against lectins, surpassing the inhibitory potential of their monovalent analogues by four to five orders of magnitude.
Review
Chemistry, Multidisciplinary
Thomas Scattolin, Giovanni Tonon, Eleonora Botter, Sebastien G. Guillet, Nikolaos V. Tzouras, Steven P. Nolan
Summary: The review focuses on the design of gold-based synthons that enable the synthesis of target complexes through simple steps under mild conditions. Mechanistic aspects of their synthesis and reactivity, as well as applications as efficient pre-catalysts, antitumor agents, and photo-emissive materials, are discussed.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Shiyi Yang, Xiang Yu, Yaxu Liu, Michele Tomasini, Lucia Caporaso, Albert Poater, Luigi Cavallo, Catherine S. J. Cazin, Steven P. Nolan, Michal Szostak
Summary: The Suzuki-Miyaura cross-coupling reaction enables the construction of biaryl ketones from inert amide bonds. However, the mechanism of C(acyl)-N bond oxidative addition and catalyst effect in this reaction remain poorly understood. This study investigates the use of [Pd(NHC)(sulfide)Cl-2] catalysts for amide N-C bond activation and presents the reaction development, kinetic studies, and reaction scope. DFT studies were also conducted to gain insight into the mechanism of C(acyl)-N bond oxidative addition and catalyst activation. The results suggest that [Pd(NHC)(sulfide)Cl-2] precatalysts could find application in C(acyl)-X bond activation in organic synthesis and catalysis.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Sofie M. P. Vanden Broeck, Nikolaos V. V. Tzouras, Marina Saab, Kristof Van Hecke, Busra Dereli, Ida Ritacco, Luigi Cavallo, Georgios C. C. Vougioukalakis, Pierre Braunstein, Steven P. P. Nolan, Andreas A. A. Danopoulos, Catherine S. J. Cazin
Summary: The 4-RN-1,3-Ar-2-imidazolium salt, R = iPr, tBu, Ar = Mes, Dipp, underwent metalation by Au-I at the C2-, C5-, and 4-RN positions, depending on the reactants and conditions used. A rare direct rearrangement of the Au-I aminide to an abnormal imidazol-5-ylidene Au-I complex was also observed, which may involve TfO- facilitated H+ transfer, according to a DFT study.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Sylwia Ostrowska, Pierre Arnaut, David J. Liptrot, Catherine S. J. Cazin, Steven P. Nolan
Summary: The synthesis, isolation, and full characterization of a new copper complex [Cu(IPr)(OC(H)(CF3)(2))] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) are reported. This copper(I) complex is a versatile synthon capable of activating various X-H bonds including C-H, N-H, and S-H bonds. [Cu(IPr)(OC(H)(CF3)(2))] was investigated as a pre-catalyst in several catalytic reactions.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Raphael Gauthier, Nikolaos V. Tzouras, Steven P. Nolan, Jean-Francois Paquin
Summary: The gold-catalyzed hydration of 2,2,2-trifluoroethyl-substituted alkynes exhibits high regioselectivity, resulting in the formation of β-trifluoromethylketones as the major products. This transformation highlights the significant directing effect of the trifluoromethyl group, mediated by its inductive effect, in gold-catalyzed addition to alkynes.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Vladislav A. Voloshkin, Yaxu Liu, Marek Belis, Min Peng, Kristof Van Hecke, Catherine S. J. Cazin, Steven P. Nolan
Summary: The synthesis of novel phosphine palladium PEPPSI and dimer complexes bearing RuPhos, SPhos and XPhos phosphines is reported. The crystal structures of XPhos Pd PEPPSI with pyridine, SPhos Pd PEPPSI with 3-chloropyridine as throw-away ligands and the RuPhos palladium dimer were obtained and compared with previously reported congeners. The catalytic activity of these complexes was examined via a C-N coupling reaction, and it was found that RuPhos complex 2b showed the highest catalytic activity with 97% yield at a low catalyst loading. The addition of 3-pentanone significantly improved the yields of phosphine dimers and PEPPSI complexes when the reactions were performed in THF.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Benon Maliszewski, Eleonora Casillo, Perrine Lambert, Fady Nahra, Catherine Cazin, Steven Nolan
Summary: This article reports an efficient olefin hydrosilylation protocol using Pt(ii)-thioether-based pre-catalysts. These simple and readily available complexes exhibit excellent catalytic performance and offer significant advantages over existing alternatives, enabling rapid and high conversions at ppm-level catalyst loadings.
CHEMICAL COMMUNICATIONS
(2023)
