Strategy for rapid and high-purity monocyclic polymers by CuAAC "click" reactions

Lonsdale, DE, Bell, CA and Monteiro, MJ (2010) Strategy for rapid and high-purity monocyclic polymers by CuAAC "click" reactions. Macromolecules, 43 7: 3331-3339. doi:10.1021/ma902597p

Author Lonsdale, DE
Bell, CA
Monteiro, MJ
Title Strategy for rapid and high-purity monocyclic polymers by CuAAC "click" reactions
Journal name Macromolecules   Check publisher's open access policy
ISSN 0024-9297
Publication date 2010-04-13
Sub-type Article (original research)
DOI 10.1021/ma902597p
Volume 43
Issue 7
Start page 3331
End page 3339
Total pages 9
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2011
Language eng
Formatted abstract
Cyclization of linear polymers by coupling end-groups together to form monocyclic polymers using the very fast Cu-catalyzed azide/alkyne cycloaddition (CuAAC) "click" reaction has been used for many polymer systems. However, the strategy based on the CuAAC methodology has not been guided by theory and relies on the very slow feed of polymer into a highly dilute reaction mixture of solvent and Cu catalyst. This leads to the production of monocyclic polymer in very low concentrations over long periods of time (> 10 h) and at high temperatures (> 100°C). In this work we use the Jacobson-Stockmayer theory to predict the % monocyclic polystyrene (c-PSTY) in a one-pot reaction at 25°C and find from an empirical relationship based on experimental diffusion-controlled rate coefficients for cyclization and condensation of α,ω-polymer chains that the Jacobson-Stockmayer theory is applicable for the CuAAC reaction. This means the % monocyclic can be predicted from theory and is independent of reaction rate parameters (such as catalytic concentration and temperature) and only dependent on polymer concentration. Given this quantitative knowledge, we investigated the effect of 1-PSTY concentration, temperature, feed rate, Cu(I)Br concentration, and linear-PSTY molecular weight to find the optimum conditions for the synthesis of monocyclic polymers. It was found that for feed rates greater than or equal to the reaction rate high % monocyclic polymers could be formed. Our strategy allowed us to produce c-PSTY (with 51 monomer units) with high purity (> 95%) at a concentration of 1.85 × 10-3 M in less than 9 min at 25°C. This is the highest concentration, shortest time, and lowest temperature, to our knowledge, that anyone has used to obtain macrocycles in high purity by the CuAAC methodology. It also allowed us to develop strategies to produce high % monocyclic from parent 1-PSTY with higher molecular weights. © 2010 American Chemical Society.
Keyword Transfer radical polymerization
Selective degradable linkages
Fragmentation chain transfer
To-end cyclization
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
Australian Institute for Bioengineering and Nanotechnology Publications
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Created: Sun, 18 Apr 2010, 00:02:33 EST