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Izadi F, Arthur‐Baidoo E, Strover LT, Yu L, Coote ML, Moad G, Denifl S. Selective Bond Cleavage in RAFT Agents Promoted by Low-Energy Electron Attachment. Angew Chem Int Ed Engl 2021; 60:19128-19132. [PMID: 34214239 PMCID: PMC8456798 DOI: 10.1002/anie.202107480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Indexed: 11/08/2022]
Abstract
Radical polymerization with reversible addition-fragmentation chain transfer (RAFT polymerization) has been successfully applied to generate polymers of well-defined architecture. For RAFT polymerization a source of radicals is required. Recent work has demonstrated that for minimal side-reactions and high spatio-temporal control these should be formed directly from the RAFT agent or macroRAFT agent (usually carbonothiosulfanyl compounds) thermally, photochemically or by electrochemical reduction. In this work, we investigated low-energy electron attachment to a common RAFT agent (cyanomethyl benzodithioate), and, for comparison, a simple carbonothioylsulfanyl compound (dimethyl trithiocarbonate, DMTTC) in the gas phase by means of mass spectrometry as well as quantum chemical calculations. We observe for both compounds that specific cleavage of the C-S bond is induced upon low-energy electron attachment at electron energies close to zero eV. This applies even in the case of a poor homolytic leaving group (. CH3 in DMTTC). All other dissociation reactions found at higher electron energies are much less abundant. The present results show a high control of the chemical reactions induced by electron attachment.
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Affiliation(s)
- Farhad Izadi
- Institut für Ionenphysik und Angewandte PhysikLeopold-Franzens Universität InnsbruckTechnikerstrasse 25A-6020InnsbruckAustria
| | - Eugene Arthur‐Baidoo
- Institut für Ionenphysik und Angewandte PhysikLeopold-Franzens Universität InnsbruckTechnikerstrasse 25A-6020InnsbruckAustria
| | | | - Li‐Juan Yu
- Research School of ChemistryAustralian National UniversityCanberraACTAustralia
| | - Michelle L. Coote
- Research School of ChemistryAustralian National UniversityCanberraACTAustralia
| | | | - Stephan Denifl
- Institut für Ionenphysik und Angewandte PhysikLeopold-Franzens Universität InnsbruckTechnikerstrasse 25A-6020InnsbruckAustria
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Izadi F, Arthur‐Baidoo E, Strover LT, Yu L, Coote ML, Moad G, Denifl S. Selektive Bindungsspaltung in RAFT Agenzien durch niederenergetische Elektronenanlagerung. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Farhad Izadi
- Institut für Ionenphysik und Angewandte Physik Leopold-Franzens Universität Innsbruck Technikerstrasse 25 A-6020 Innsbruck Österreich
| | - Eugene Arthur‐Baidoo
- Institut für Ionenphysik und Angewandte Physik Leopold-Franzens Universität Innsbruck Technikerstrasse 25 A-6020 Innsbruck Österreich
| | | | - Li‐Juan Yu
- Research School of Chemistry Australian National University Canberra ACT Australien
| | - Michelle L. Coote
- Research School of Chemistry Australian National University Canberra ACT Australien
| | - Graeme Moad
- CSIRO Manufacturing Clayton VIC 3168 Australien
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik Leopold-Franzens Universität Innsbruck Technikerstrasse 25 A-6020 Innsbruck Österreich
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López-Pérez L, Maldonado-Textle H, Elizalde-Herrera LE, Telles-Padilla JG, Guerrero-Santos R, Collins S, Jiménez-Regalado EJ, St Thomas C. Methylation of poly(acrylic acid), prepared using RAFT polymerization, with trimethylsilyldiazomethane: A metamorphosis of the thiocarbonyl group to a thiol-end group. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.02.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Chernikova EV, Sivtsov EV. Reversible addition-fragmentation chain-transfer polymerization: Fundamentals and use in practice. POLYMER SCIENCE SERIES B 2017. [DOI: 10.1134/s1560090417020038] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Fuchs AV, Thurecht KJ. Stability of Trithiocarbonate RAFT Agents Containing Both a Cyano and a Carboxylic Acid Functional Group. ACS Macro Lett 2017; 6:287-291. [PMID: 35650904 DOI: 10.1021/acsmacrolett.7b00100] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The hydrolytic degradation of widely used cyano-containing, acid-bearing trithiocarbonate reversible addition-fragmentation chain-transfer (RAFT) agents has been identified and shown to effect the RAFT polymerization and end-group fidelity of PMMA polymers. The hydrolysis occurred when the RAFT agents were stored under the recommended conditions. Degradation was identified in both commercially available and popular synthetic RAFT agents. 1H and 13C NMR as well as mass spectroscopy show that the cyano functionality hydrolyzes to the amide adduct. Doping of this amide degradation product into RAFT polymerizations of MMA results in increased dispersities and changes in expected end-group fidelities. The ability to identify this degradation product and remove it from the RAFT agent before use will allow better control over polymer properties and postmodification processes commonly used in complex polymer systems, nanomedicines, and bioconjugates.
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Affiliation(s)
- Adrian V. Fuchs
- Australian
Institute of Bioengineering and Nanotechnology and Centre for Advanced
Imaging, University of Queensland, Brisbane 4072, Australia
- ARC
Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville 3052, Victoria, Australia
| | - Kristofer J. Thurecht
- Australian
Institute of Bioengineering and Nanotechnology and Centre for Advanced
Imaging, University of Queensland, Brisbane 4072, Australia
- ARC
Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville 3052, Victoria, Australia
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Abstract
Stimuli-responsive polymers respond to a variety of external stimuli, which include optical, electrical, thermal, mechanical, redox, pH, chemical, environmental and biological signals. This paper is concerned with the process of forming such polymers by RAFT polymerization.
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Moad G. Mechanism and Kinetics of Dithiobenzoate-Mediated RAFT Polymerization - Status of the Dilemma. MACROMOL CHEM PHYS 2013. [DOI: 10.1002/macp.201300562] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Graeme Moad
- CSIRO Materials Science and Engineering; Bag 10 Clayton South VIC 3169 Australia
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Moad G, Rizzardo E, Thang SH. RAFT Polymerization and Some of its Applications. Chem Asian J 2013; 8:1634-44. [DOI: 10.1002/asia.201300262] [Citation(s) in RCA: 230] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Indexed: 11/08/2022]
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Moad G, Rizzardo E, Thang SH. Fundamentals of RAFT Polymerization. FUNDAMENTALS OF CONTROLLED/LIVING RADICAL POLYMERIZATION 2013. [DOI: 10.1039/9781849737425-00205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This chapter sets out to describe the fundamental aspects of radical polymerization with reversible addition-fragmentation chain transfer (RAFT polymerization). Following a description of the mechanism we describe aspects of the kinetics of RAFT polymerization, how to select a RAFT agent to achieve optimal control over polymer molecular weight, composition and architecture, and how to avoid side reactions which might lead to retardation or inhibition.
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Affiliation(s)
- Graeme Moad
- CSIRO Materials Science and Engineering Bayview Ave, Clayton, Victoria 3168 Australia
| | - Ezio Rizzardo
- CSIRO Materials Science and Engineering Bayview Ave, Clayton, Victoria 3168 Australia
| | - San H. Thang
- CSIRO Materials Science and Engineering Bayview Ave, Clayton, Victoria 3168 Australia
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Affiliation(s)
- Daniel J. Keddie
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria, Australia
| | - Graeme Moad
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria, Australia
| | - Ezio Rizzardo
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria, Australia
| | - San H. Thang
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria, Australia
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Yhaya F, Binauld S, Callari M, Stenzel MH. One-Pot Endgroup-Modification of Hydrophobic RAFT Polymers with Cyclodextrin by Thiol-ene Chemistry and the Subsequent Formation of Dynamic Core–Shell Nanoparticles Using Supramolecular Host–Guest Chemistry. Aust J Chem 2012. [DOI: 10.1071/ch12158] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Poly(methyl methacrylate) PMMA, synthesized using reversible addition fragmentation chain transfer (RAFT) polymerization, was heated in a solvent at 100°C for 24 h leading to the loss of the RAFT endfunctionality and the complete conversion into a vinyl group. Mono(6-deoxy-6-mercapto)-β-cyclodextrin (β-CD-SH) was subsequently clicked onto the polymer by a thiol-ene reaction leading to PMMA with one β-CD as a terminal group (PMMA70–β-CD). Meanwhile, a RAFT agent with an adamantyl group has been prepared for the polymerization of 2-hydroxyethyl acrylate (HEA) leading to PHEA95–Ada. Two processes were employed to generate core–shell nanoparticles from these two polymers: a one-step approach that employs a solution of both polymers at stoichiometric amounts in DMF, followed by the addition of water, and a two step process that uses PMMA solid particles with surface enriched with β-CD in water, which have a strong tendency to aggregate, followed by the addition of PHEA95–Ada in water. Both pathways led to stable core–shell nanoparticles of ~150 nm in size. Addition of free β-CD competed with the polymer bound β-CD releasing the PHEA hairs from the particle surface. As a result, the PMMA particles started agglomerating resulting in a cloudy solution. A similar effect was observed when heating the solution. Since the equilibrium constant between β-CD and adamantane decreases with increasing temperature, the stabilizing PHEA chains cleaved from the surface and the solution turned cloudy due to the aggregation of the naked PMMA spheres. This process was reversible and with decreasing temperature the core–shell nanoparticles formed again leading to a clear solution.
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Moad G, Rizzardo E, Thang SH. Living Radical Polymerization by the RAFT Process – A Third Update. Aust J Chem 2012. [DOI: 10.1071/ch12295] [Citation(s) in RCA: 825] [Impact Index Per Article: 68.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This paper provides a third update to the review of reversible deactivation radical polymerization (RDRP) achieved with thiocarbonylthio compounds (ZC(=S)SR) by a mechanism of reversible addition-fragmentation chain transfer (RAFT) that was published in June 2005 (Aust. J. Chem. 2005, 58, 379). The first update was published in November 2006 (Aust. J. Chem. 2006, 59, 669) and the second in December 2009 (Aust. J. Chem. 2009, 62, 1402). This review cites over 700 publications that appeared during the period mid 2009 to early 2012 covering various aspects of RAFT polymerization which include reagent synthesis and properties, kinetics and mechanism of polymerization, novel polymer syntheses, and a diverse range of applications. This period has witnessed further significant developments, particularly in the areas of novel RAFT agents, techniques for end-group transformation, the production of micro/nanoparticles and modified surfaces, and biopolymer conjugates both for therapeutic and diagnostic applications.
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Rizzardo E, Solomon DH. On the Origins of Nitroxide Mediated Polymerization (NMP) and Reversible Addition–Fragmentation Chain Transfer (RAFT). Aust J Chem 2012. [DOI: 10.1071/ch12194] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The early experiments on radical polymerization, which were to lead to a study of nitroxide trapping of the initiation step and the interest in defect groups, particularly the macromonomers formed by termination by disproportionation, are discussed. Results from the nitroxide trapping clearly show that the initiation step ranges from simple clean addition to the head of the monomer, to complex addition/abstraction reactions. Careful selection of the monomer/initiation system is emphasized with particular reference to two common monomers, styrene and methyl methacrylate, and two initiating radicals, t-butoxy and benzoyloxy. The discovery of nitroxide mediated polymerization (NMP) from observations made during the nitroxide trapping work is reported and the ability to have a living radical system demonstrated with numerous examples. Similarly, the study of the copolymerization of macromonomers, formed by disproportionation of the propagating chains, is discussed with the discovery of β-scission and an early form of addition–fragmentation reported. The evolution of reversible addition–fragmentation chain transfer (RAFT) to a highly versatile and commercially attractive radical system is reported and the detailed chemistry behind the discovery of this living radical system discussed. Both NMP and RAFT enable the synthesis of structures not previously possible by radical polymerization and in some cases not possible by any other process.
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