Michelle L Coote

Publications (164) View all

• Article: Reversible Addition–Fragmentation Chain Transfer Polymerization of Vinyl Chloride

  Carlos M. R. Abreu, Patrícia V. Mendonça, Arménio C. Serra, Jorge F. J. Coelho, Anatoliy V. Popov, Ganna Gryn’ova, Michelle L. Coote, Tamaz Guliashvili
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  ABSTRACT: doi: 10.1021/ma300064j
  Macromolecules 02/2013; 45(5):2200-2208. · 5.17 Impact Factor
• Article: Computational Evaluation of the Sulfonyl Radical as a Universal Leaving Group for RAFT Polymerisation*

  Ganna Gryn’ova, Tamaz Guliashvili, Krzysztof Matyjaszewski, Michelle L. Coote
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  ABSTRACT: The present study investigates the performance of the sulfonyl radical, i.e. •SO2Ph, as a universal leaving group in reversible addition–fragmentation chain-transfer (RAFT) polymerisation. The sulfonyl radical is widely used as a radical initiator and has already been proved successful as a leaving group in an atom-transfer radical polymerisation. Our results, obtained using high-level ab initio computational methodology under relevant experimental conditions, indicate superior performance of the sulfonyl compared with a reference cyanoisopropyl group in controlling RAFT of a wide range of monomers. Importantly, the presence of sulfonyl chain ends in the polymers so formed opens attractive possibilities for further functionalisation. Potential synthetic routes to the R-sulfonyl RAFT agents are discussed.
  Australian Journal of Chemistry 01/2013; 66(3):308-313. · 2.34 Impact Factor
• Source

  Available from: Kim K Oehlenschlaeger

  Article: Harnessing entropy to direct the bonding/debonding of polymer systems based on reversible chemistry

  Nathalie K. Guimard, Junming Ho, Josef Brandt, Ching Yeh Lin, Mansoor Namazian, Jan O. Mueller, Kim K. Oehlenschlaeger, Stefan Hilf, Albena Lederer, Friedrich G. Schmidt, Michelle L. Coote, Christopher Barner-Kowollik
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  ABSTRACT: The widely accepted approach for controlling polymer debonding/rebonding properties in responsive materials has been to purposefully engineer the functional end-groups responsible for monomer dynamic bonding. Here, however, we evidence that the debonding temperature of a polymer can also be tuned by changing the chain length of the polymer building blocks, thus altering the entropy released on debonding. Entropy driven debonding, as governed by building block chain length, is suggested theoretically and realized experimentally for two Diels-Alder polymer systems, each based on a different difunctional diene and a common difunctional dienophile. In each case a significant decrease (as much as 60 [degree]C) in the retro Diels-Alder temperature was observed when the chain length of the difunctional dienophile building block was increased. These results have the potential to fundamentally change the approach utilized to design materials capable of bonding reversibly on demand.
  Chemical Science. 01/2013;
• Article: Reversible Cyclopropane Ring-Cleavage Reactions within Etheno-Bridged [4.3.1]Propelladiene Frameworks Leading to Aza- and Oxa-[5.6.5.6]fenestratetraenes.

  Nora Heinrich, Anthony C Willis, Ian A Cade, Junming Ho, Michelle L Coote, Martin G Banwell
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  ABSTRACT: Opening and closing a chemical window: Oxidation of the etheno-bridged [4.3.1]propelladienol 1 with pyridinium chlorochromate (PCC) affords oxa[5.6.5.6]fenestratetraene 2. The reduction of 2 with diisobutylaluminum hydride (DIBAl-H) leads to the regeneration of its precursor (1; see scheme). These transformations most likely involve a [3,5]-sigmatropic rearrangement process.
  Chemistry 09/2012; 18(43):13585-8. · 5.93 Impact Factor
• Article: The use of spin traps for the kinetic investigation of elementary events of pseudoliving radical reversible addition-fragmentation chain-transfer polymerization

  V. B. Golubev, A. N. Filippov, E. V. Chernikova, M. L. Coote, C. Y. Lin, G. Gryn’ova
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  ABSTRACT: The spin-trapping technique is used for the first time to study the kinetics and mechanism of addition and fragmentation elementary events in reversible addition-fragmentation chain-transfer pseudoliving radical polymerization. As shown by the example of the spin-trap-reversible addition-fragmentation chaintransfer agent model system, the constants of addition (substitution) of the model tert-butyl radical to polymeric reversible addition-fragmentation chain-transfer agents (poly(styrene dithiobenzoate), poly(n-butyl acrylate) dithiobenzoate, etc.) are one to two orders of magnitude higher than the constants of addition reactions involving low-molecular-mass reversible addition-fragmentation chain-transfer agents (tert-butyl dithiobenzoate, benzyl dithiobenzoate, di-tert-butyl trithiocarbonate, and dibenzyl trithiocarbonate). This circumstance makes it possible to significantly widen the synthetic possibilities of reversible addition-fragmentation chain-transfer polymerization. Rate constants of the fragmentation reaction for a number of intermediates are estimated, and the relationship between their structure and stability is ascertained. For the model reaction of the interaction (addition and fragmentation) of the tert-butyl radical with low-molecular-mass reversible addition-fragmentation chain-transfer agents, equilibrium constants are calculated via the methods of computational chemistry.
  Polymer Science Series C 05/2012; 53(1):14-26. · 0.29 Impact Factor