The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers
The synthesis of 3-arm star polymers from reversible addition-fragmentation chain transfer (RAFT)-prepared precursor homopolymers in combination with thiol-ene click chemistry is described. Homopolymers of n-butyl acrylate and N,N-diethylacrylamide were prepared with 1-cyano-1-methylethyl dithiobenz...
| Main Authors: | , , , |
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| Format: | Journal Article |
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Elsevier Ltd
2009
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| Online Access: | http://hdl.handle.net/20.500.11937/12308 |
| _version_ | 1848748040489271296 |
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| author | Chan, J. Yu, B. Hoyle, C. Lowe, Andrew |
| author_facet | Chan, J. Yu, B. Hoyle, C. Lowe, Andrew |
| author_sort | Chan, J. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The synthesis of 3-arm star polymers from reversible addition-fragmentation chain transfer (RAFT)-prepared precursor homopolymers in combination with thiol-ene click chemistry is described. Homopolymers of n-butyl acrylate and N,N-diethylacrylamide were prepared with 1-cyano-1-methylethyl dithiobenzoate and 2,2'-azobis(2-methylpropionitrile) yielding materials with polydispersity indices (Mw/Mn) = 1.18 and controlled molecular weights as determined by a combination of NMR spectroscopy, size exclusion chromatography (SEC), and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Subsequent one-pot reaction of homopolymer, hexylamine (HexAM), dimethylphenylphosphine (DMPP), and trimethylolpropane triacrylate (TMPTA) results in cleavage of the thiocarbonylthiol end-group (by HexAM) of the homopolymer yielding a macromolecular thiol that undergoes DMPP-initiated thiol-Michael addition to TMPTA yielding 3-arm star polymers. The presence of DMPP is demonstrated to serve an important second role in effectively suppressing the presence of any polymeric disulfide as determined by SEC. Such phosphine-mediated thiol-ene reactions are shown to be extremely rapid, as verified by a combination of FTIR and NMR spectroscopies, with complete consumption of the C{double bond, long}C bonds occurring in a matter of min. MALDI-TOF MS and SEC were used to verify the formation of 3-arm stars. A broadening in the molecular weight distribution (Mw/Mn ~ 1.35) was observed by SEC that was attributed to the presence of residual homopolymer and possibly 2-arm stars formed from trimethylolpropane diacrylate impurity. Interestingly, the MALDI analysis also indicated the presence of 1- and 2-arm species most likely formed from the fragmentation of the parent 3-arm star during analysis. Finally, a control experiment verified that the consumption of C{double bond, long}C bonds does not occur via a radical pathway. © 2009 Elsevier Ltd. All rights reserved. |
| first_indexed | 2025-11-14T06:58:43Z |
| format | Journal Article |
| id | curtin-20.500.11937-12308 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:58:43Z |
| publishDate | 2009 |
| publisher | Elsevier Ltd |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-123082017-10-02T02:28:09Z The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers Chan, J. Yu, B. Hoyle, C. Lowe, Andrew The synthesis of 3-arm star polymers from reversible addition-fragmentation chain transfer (RAFT)-prepared precursor homopolymers in combination with thiol-ene click chemistry is described. Homopolymers of n-butyl acrylate and N,N-diethylacrylamide were prepared with 1-cyano-1-methylethyl dithiobenzoate and 2,2'-azobis(2-methylpropionitrile) yielding materials with polydispersity indices (Mw/Mn) = 1.18 and controlled molecular weights as determined by a combination of NMR spectroscopy, size exclusion chromatography (SEC), and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Subsequent one-pot reaction of homopolymer, hexylamine (HexAM), dimethylphenylphosphine (DMPP), and trimethylolpropane triacrylate (TMPTA) results in cleavage of the thiocarbonylthiol end-group (by HexAM) of the homopolymer yielding a macromolecular thiol that undergoes DMPP-initiated thiol-Michael addition to TMPTA yielding 3-arm star polymers. The presence of DMPP is demonstrated to serve an important second role in effectively suppressing the presence of any polymeric disulfide as determined by SEC. Such phosphine-mediated thiol-ene reactions are shown to be extremely rapid, as verified by a combination of FTIR and NMR spectroscopies, with complete consumption of the C{double bond, long}C bonds occurring in a matter of min. MALDI-TOF MS and SEC were used to verify the formation of 3-arm stars. A broadening in the molecular weight distribution (Mw/Mn ~ 1.35) was observed by SEC that was attributed to the presence of residual homopolymer and possibly 2-arm stars formed from trimethylolpropane diacrylate impurity. Interestingly, the MALDI analysis also indicated the presence of 1- and 2-arm species most likely formed from the fragmentation of the parent 3-arm star during analysis. Finally, a control experiment verified that the consumption of C{double bond, long}C bonds does not occur via a radical pathway. © 2009 Elsevier Ltd. All rights reserved. 2009 Journal Article http://hdl.handle.net/20.500.11937/12308 10.1016/j.polymer.2009.04.030 Elsevier Ltd restricted |
| spellingShingle | Chan, J. Yu, B. Hoyle, C. Lowe, Andrew The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers |
| title | The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers |
| title_full | The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers |
| title_fullStr | The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers |
| title_full_unstemmed | The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers |
| title_short | The nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with RAFT-prepared homopolymers |
| title_sort | nucleophilic, phosphine-catalyzed thiol-ene click reaction and convergent star synthesis with raft-prepared homopolymers |
| url | http://hdl.handle.net/20.500.11937/12308 |