[en] We report here metal-free strategies using organocatalysis based on supramolecular recognition for the ring-opening polymerization (ROP) of several cyclic phosphate monomers (CPMs) by a variety of organocatalysts such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]undec-5-ene (TBD), and a bicomponent thiourea−tertiary amine catalyst. Each of these catalysts is efficient to produce linear polyphosphoesters (PPEs) from CPMs but with different sensitivity toward transesterification side reactions. The strong basicity of DBU is sufficient to activate an alcohol initiating the polymerization in the absence of any other cocatalyst. Nevertheless, side chain transfer reactions leading to branched and/or cyclic polymeric structures are observed, especially for high monomer conversion. Unlike DBU, TBD is a dual catalyst activating both the alcohol and the monomer. This dual activation allows shorter polymerization time, but SEC analyses of polyphosphates reveal bimodal molecular weight distribution due to chains coupling. Finally, a mixture of DBU and thiourea (TU) appears by far the most efficient catalyst to carry out fast and controlled polymerization while minimizing transesterification reactions, even at near-complete conversion. Compared with polymerizations carried out with Sn(Oct)2 as a metal catalyst, the control of polymerization is much better so that it is possible to prepare polyphosphoesters (PPEs) with molecular weight close to 70 000 g mol−1 and polydispersity index below 1.10. Simultaneous activation by TU of both CPMs and the alcohol group of the initiator by DBU proves to be an effective and robust ROP catalytic system to synthesize polymers with predictable molecular weight and narrow polydispersity. The chain extension experiments through the use of hydroxy end- capped PPEs as macroinitiators confirm the controlled/living nature of the DBU/TU-catalyzed ROP of CPMs and pave the way to the synthesis of block copolymers based on polyphosphates.
Research center :
Center for Education and Research on Macromolecules (CERM)
Disciplines :
Chemistry Materials science & engineering
Author, co-author :
Clement, Benoît ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Grignard, Bruno ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Koole, Leo; Maastricht University (The Netherlands), Lead Partner of the BioMiMedics Interreg EMR IV-A consortium
Jérôme, Christine ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Lecomte, Philippe ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Language :
English
Title :
Metal-free strategies for the synthesis of functional and well-defined polyphosphoesters
Publication date :
12 June 2012
Journal title :
Macromolecules
ISSN :
0024-9297
eISSN :
1520-5835
Publisher :
American Chemical Society, Washington, United States - District of Columbia
The Interreg Euregio Meuse Rhine IV-A consortium BioMiMedics The European Union (through Interreg IV-A) The government of Wallonia (Belgium) The “Provincie Nederlands Limburg” (The Netherlands) BELSPO - SPP Politique scientifique - Service Public Fédéral de Programmation Politique scientifique F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE] The "Région Wallonne" and the "FEDER" in the frame of the SINOPLISS project
Iwasaki, Y.; Wachiralarpphaithoon, C.; Akiyoshi, K. Macromolecules 2007, 40, 8136-8138
Xiao, C.-S.; Wang, Y.-C.; Du, J.-Z.; Chen, X.-S.; Wang, J. Macromolecules 2006, 39, 6825-6831
Wang, Y. C.; Shen, S. Y.; Wu, Q. P.; Chen, D. P.; Wang, J.; Steinhoff, G.; Ma, N. Macromolecules 2006, 39 (26) 8992-8998
Chen, D. P.; Wang, J. Macromolecules 2006, 39, 473-475
Dove, A. P.; Pratt, R. C.; Lohmeijer, B. G. G.; Waymouth, R. M.; Hedrick, J. L. J. Am. Chem. Soc. 2005, 127 (40) 13798-13799
Lohmeijer, B. G. G.; Pratt, R. C.; Leibfarth, F.; Logan, J. W.; Long, D. A.; Dove, A. P.; Nederberg, F.; Choi, J.; Wade, C.; Waymouth, R. M.; Hedrick, J. L. Macromolecules 2006, 39, 8574-8583
Pratt, R. C.; Lohmeijer, B. G. G.; Long, D. A.; Waymouth, R. M.; Hedrick, J. L. J. Am. Chem. Soc. 2006, 128, 4556-4557
Pratt, R. C.; Lohmeijer, B. G. G.; Long, D. A.; Lundberg, P. N.; Dove, A. P.; Li, H.; Wade, C. G.; Waymouth, R. M.; Hedrick, J. L. Macromolecules 2006, 39, 7863-7871
Iwasaki, Y.; Yamaguchi, E. Macromolecules 2010, 43, 2664-2666
Zhang, S.; Li, A.; Zou, J.; Lin, Y. L.; Wooley, K. L. ACS Macro Lett. 2012, 1, 328-333
Kowalski, A.; Duda, A.; Penczek, S. Macromolecules 2000, 33, 689-695
Kowalski, A.; Duda, A.; Penczek, S. Macromolecules 2000, 33, 7359-7370
Kowalski, A.; Libiszowski, J.; Biela, T.; Cypryk, M.; Duda, A.; Penczek, S. Macromolecules 2005, 38, 8170-8176
Kaljurand, I.; Kütt, A.; Sooväli, L.; Rodima, T.; Mäemets, V.; Leito, I.; Koppel, I. A. J. Org. Chem. 2005, 70, 1019-1028
