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Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts
The N‐heterocyclic carbene‐phosphinidene adducts (NHC)PH were reacted with AlMe(3) in toluene to afford the monoaluminum complexes [{(IDipp)PH}AlMe(3)] and [{(IMes)PH}AlMe(3)] (IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene, IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene). In cont...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048956/ https://www.ncbi.nlm.nih.gov/pubmed/33555047 http://dx.doi.org/10.1002/chem.202100482 |
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author | Bhattacharjee, Jayeeta Peters, Marius Bockfeld, Dirk Tamm, Matthias |
author_facet | Bhattacharjee, Jayeeta Peters, Marius Bockfeld, Dirk Tamm, Matthias |
author_sort | Bhattacharjee, Jayeeta |
collection | PubMed |
description | The N‐heterocyclic carbene‐phosphinidene adducts (NHC)PH were reacted with AlMe(3) in toluene to afford the monoaluminum complexes [{(IDipp)PH}AlMe(3)] and [{(IMes)PH}AlMe(3)] (IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene, IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene). In contrast, the dialuminum complex [{((Me)IMes)PH}(AlMe(3))(2)] was obtained for (Me)IMes=1,3‐bis(2,4,6‐trimethylphenyl)‐4,5‐dimethylimidazolin‐2‐ylidene. These complexes served as initiators for the efficient ring‐opening polymerization of rac‐lactide in toluene at 60 °C. High degrees of isoselectivity were found for the poly(rac‐lactide) obtained in the presence of the monoaluminum complexes (P (m) up to 0.92, T (m) up to 191 °C), whereas almost atactic polymers were produced by the dialuminum complex. Detailed mechanistic studies reveal that the polymerization proceeds via a coordination‐insertion mechanism with the carbene‐phosphinidene ligands acting as stereodirecting groups. |
format | Online Article Text |
id | pubmed-8048956 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-80489562021-04-20 Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts Bhattacharjee, Jayeeta Peters, Marius Bockfeld, Dirk Tamm, Matthias Chemistry Communications The N‐heterocyclic carbene‐phosphinidene adducts (NHC)PH were reacted with AlMe(3) in toluene to afford the monoaluminum complexes [{(IDipp)PH}AlMe(3)] and [{(IMes)PH}AlMe(3)] (IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene, IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene). In contrast, the dialuminum complex [{((Me)IMes)PH}(AlMe(3))(2)] was obtained for (Me)IMes=1,3‐bis(2,4,6‐trimethylphenyl)‐4,5‐dimethylimidazolin‐2‐ylidene. These complexes served as initiators for the efficient ring‐opening polymerization of rac‐lactide in toluene at 60 °C. High degrees of isoselectivity were found for the poly(rac‐lactide) obtained in the presence of the monoaluminum complexes (P (m) up to 0.92, T (m) up to 191 °C), whereas almost atactic polymers were produced by the dialuminum complex. Detailed mechanistic studies reveal that the polymerization proceeds via a coordination‐insertion mechanism with the carbene‐phosphinidene ligands acting as stereodirecting groups. John Wiley and Sons Inc. 2021-03-03 2021-04-01 /pmc/articles/PMC8048956/ /pubmed/33555047 http://dx.doi.org/10.1002/chem.202100482 Text en © 2021 The Authors. Published by Wiley-VCH GmbH https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Communications Bhattacharjee, Jayeeta Peters, Marius Bockfeld, Dirk Tamm, Matthias Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts |
title | Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts |
title_full | Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts |
title_fullStr | Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts |
title_full_unstemmed | Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts |
title_short | Isoselective Polymerization of rac‐Lactide by Aluminum Complexes of N‐Heterocyclic Carbene‐Phosphinidene Adducts |
title_sort | isoselective polymerization of rac‐lactide by aluminum complexes of n‐heterocyclic carbene‐phosphinidene adducts |
topic | Communications |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048956/ https://www.ncbi.nlm.nih.gov/pubmed/33555047 http://dx.doi.org/10.1002/chem.202100482 |
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