Advertisement

Chinese Journal of Polymer Science

, Volume 36, Issue 2, pp 231–236 | Cite as

Stereoselective ring-opening polymerization of rac-lactide by bulky chiral and achiral N-heterocyclic carbenes

  • Hui Li
  • Bai-Ru Ai
  • Miao Hong
Article

Abstract

Despite the extraordinary success has been achieved in metal catalyst-promoted stereoselective ring-opening polymerization (ROP) of rac-lactide (rac-LA), well-controlled stereoselective rac-LA ROP by organic catalyst still remains a scientific challenge. Here we report our investigations into organocatalytic stereoselective ROP of rac-LA by utilizing novel bulky chiral and achiral N-heterocyclic carbenes (NHC), 1,3-bis-(1′-naphthylethyl)imidazolin-2-ylidene. The effect of polymerization conditions (e.g. solvent, temperature, alcohol initiator) on ROP behavior by these bulky NHCs has been fully studied, leading to the formation of isotactic-rich stereoblock polylactide (Pi = 0.81) under optimized conditions with high activity (Conv. = 98% in 30 min) and narrow molecular weight dispersity (Ɖ = 1.05).

Keywords

Polylactide Ring-opening polymerization Stereoselectivity Organic catalyst N-heterocyclic carbene 

Notes

Acknowledgments

This work was financially supported by the Science and Technology Commission of Shanghai Municipality (No. 17JC1401200).

References

  1. 1.
    Auras, R., “Poly(lactic acid) in encyclopedia of polymer science and technology, Vol. 10”, ed. by Mark, H. F., Wiley, Hoboken, 2014, p. 165.Google Scholar
  2. 2.
    Stanford, M. J.; Dove, A. P. Stereocontrolled ring-opening polymerisation of lactide. Chem. Soc. Rev. 2010, 39(2), 486–494.CrossRefGoogle Scholar
  3. 3.
    Thomas, C. M. Stereocontrolled ring-opening polymerization of cyclic esters: synthesis of new polyester microstructures. Chem. Soc. Rev. 2010, 39(20), 165–173.CrossRefGoogle Scholar
  4. 4.
    Carpentier, J. F. Rare-earth complexes supported by tripodal tetradentate bis(phenolate) ligands: a privileged class of catalysts for ring-opening polymerization of cyclic esters. Organometallics 2015, 34(17), 4175–4189.CrossRefGoogle Scholar
  5. 5.
    Sauer, A.; Kapelski, A.; Fliedel, C.; Dagorne, S.; Kol, M.; Okuda, J. Structurally well-defined group 4 metal complexes as initiators for the ring-opening polymerization of lactide monomers. Dalton Trans. 2013, 42(25), 9007–9023.CrossRefGoogle Scholar
  6. 6.
    O’Keefe, B. J.; Hillmyer, M. A.; Tolman, W. Polymerization of lactide and related cyclic esters by discrete metal complexes. J. Chem. Soc., Dalton Trans. 2001, 15(15), 2215–2224.CrossRefGoogle Scholar
  7. 7.
    Dechy-Cabaret, O.; Martin-Vaca, B.; Bourissou, D. Controlled ring-opening polymerization of lactide and glycolide. Chem. Rev. 2004, 104(12), 6147–6176.CrossRefGoogle Scholar
  8. 8.
    Carpentier, J. F. Discrete metal catalysts for stereoselective ring-opening polymerization of chiral racemic ²-lactones. Macromol. Rapid Commun. 2010, 31(19), 1696–1705.CrossRefGoogle Scholar
  9. 9.
    Jérôme, C.; Lecomte, P. Recent advances in the synthesis of aliphatic polyesters by ring-opening polymerization. Adv. Drug Delivery. Rev. 2008, 60(9), 1056–1076.CrossRefGoogle Scholar
  10. 10.
    Wu, J.; Yu, T. L.; Chen, C. T.; Lin, C. C. Recent developments in main group metal complexes catalyzed/initiated polymerization of lactides and related cyclic esters. Coord. Chem. Rev. 2006, 250(5), 602–626.CrossRefGoogle Scholar
  11. 11.
    Ovitt, T. M.; Coates, G. W. Stereoselective ring-opening polymerization of meso-lactide: synthesis of syndiotactic poly(lactic acid). J. Am. Chem. Soc. 1999, 121(16), 4072–4073.CrossRefGoogle Scholar
  12. 12.
    Rosen, T.; Goldberg, I.; Venditto, V.; Kol, M. Tailor-made stereoblock copolymers of poly(lactic acid) by a truly living polymerization catalyst. J. Am. Chem. Soc. 2016, 138(37), 12041–12044.CrossRefGoogle Scholar
  13. 13.
    Myers, D.; White, A. J. P.; Forsyth, C. M.; Bown, M.; Williams, C. K. Phosphasalen indium complexes showing high rates and isoselectivities in rac-lactide polymerizations. Angew. Chem. Int. Ed. 2017, 56(19), 5277–5282.CrossRefGoogle Scholar
  14. 14.
    Xu, T. Q.; Yang, G. W.; Liu, C.; Lu, X. B. Highly robust yttrium bis(phenolate) ether catalysts for excellent isoselective ring-opening polymerization of racemic lactide. Macromolecules 2017, 50(2), 515–522.CrossRefGoogle Scholar
  15. 15.
    Robert, C.; Schmid, T. E.; Richard, V.; Haquette, P.; Raman, S. K.; Rager, M.; Gauvin, R. M.; Morin, Y.; Trivelli, X.; Guérineau, V.; Rosal, I.; Maron, L.; Thomas, C. M. Mechanistic aspects of the polymerization of lactide using a highly efficient aluminum(III) catalytic system. J. Am. Chem. Soc. 2017, 139(17), 6217–6225.CrossRefGoogle Scholar
  16. 16.
    Douglas, A. F.; Patrick, B. O.; Mehrkhodavandi, P. A highly active and site selective indium catalyst for lactide polymerization. Angew. Chem. Int. Ed. 2008, 47(12), 2290–2293.CrossRefGoogle Scholar
  17. 17.
    Bakewell, C.; White, A. J. P.; Long, N. J.; Williams, C. K. Metal-size influence in iso-selective lactide polymerization. Angew. Chem. Int. Ed. 2014, 53(35), 9226–9230.CrossRefGoogle Scholar
  18. 18.
    Mou, Z.; Liu, B.; Wang, M. Y.; Xie, H. Y.; Li, P.; Li, L.; Li, S. H.; Cui, D. M. Isoselective ring-opening polymerization of rac-lactide initiated by achiral heteroscorpionate zwitterionic zinc complexes. Chem. Commun. 2014, 50(77), 11411–11414.CrossRefGoogle Scholar
  19. 19.
    Ovitt, T. M.; Coates, G. W. Stereochemistry of lactide polymerization with chiral catalysts: new opportunities for stereocontrol using polymer exchange mechanisms. J. Am. Chem. Soc. 2002, 124(7), 1316–1326.CrossRefGoogle Scholar
  20. 20.
    Nomura, N.; Ishii, R.; Akakura, M.; Aoi, K. Stereoselective ring-opening polymerization of racemic lactide using aluminum-achiral ligand complexes: exploration of a chain-end control mechanism. J. Am. Chem. Soc. 2002, 124(21), 5938–5939.CrossRefGoogle Scholar
  21. 21.
    Kiesewetter, M. K.; Shin, E. J.; Hedrick, J. L.; Waymouth, R. M. Organocatalysis: opportunities and challenges for polymer synthesis. Macromolecules 2010, 43(43), 2093–2107.CrossRefGoogle Scholar
  22. 22.
    Kamber, N. E.; Jeong, W.; Waymouth, R. M.; Pratt, R. C.; Lohmeijer, B. G. G.; Hedrick, J. L. Organocatalytic ring-opening polymerization. Chem. Rev. 2007, 107(12), 5813–5840.CrossRefGoogle Scholar
  23. 23.
    Lin, B. H.; Waymouth, R. M. Urea anions: simple, fast, and selective catalysts for ring-opening polymerizations. J. Am. Chem. Soc. 2017, 139(4), 1645–1652.CrossRefGoogle Scholar
  24. 24.
    Zhang, X. Y.; Jones, G. O.; Hedrick, J. L.; Waymouth, R. M. Fast and selective ring-opening polymerizations by alkoxides. Nat. Chem. 2016, 8(11), 1047–1053.CrossRefGoogle Scholar
  25. 25.
    Makiguchi, K.; Yamanaka, T.; Kakuchi, T.; Terada, M.; Satoh, T. Binaphthol-derived phosphoric acids as efficient chiral organocatalysts for the enantiomer-selective polymerization of rac-lactide. Chem. Commun. 2014, 50(22), 2883–2885.CrossRefGoogle Scholar
  26. 26.
    Miyake, G. M.; Chen, E. Y. X. Cinchona alkaloids as stereoselective organocatalysts for the partial kinetic resolution polymerization of rac-lactide. Macromolecules 2011, 44(11), 4116–4124.CrossRefGoogle Scholar
  27. 27.
    Zhu, J. B.; Chen, E. Y. X. From meso-lactide to isotactic polylactide: epimerization by B/N lewis pairs and kinetic resolution by organic catalysts. J. Am. Chem. Soc. 2015, 137(39), 12506–12509.CrossRefGoogle Scholar
  28. 28.
    Zhang, L.; Nederberg, F.; Messman, J. M.; Pratt, R. C.; Hedrick, J. L.; Wade, C. G. Organocatalytic stereoselective ring-opening polymerization of lactide with dimeric phosphazene bases. J. Am. Chem. Soc. 2007, 129(42), 12610–12611.CrossRefGoogle Scholar
  29. 29.
    Dove, A. P.; Li, H. B.; Pratt, R. C.; Lohmeijer, B. G. G.; Culkin, D. A.; Waymouth, R. M.; Hedrick, J. L. Stereoselective polymerization of rac-and meso-lactide catalyzed by sterically encumbered N-heterocyclic carbenes. Chem. Commun. 2006, 27(27), 2881–2883.CrossRefGoogle Scholar
  30. 30.
    Herrmann, W. A.; Goossen, L. J.; Artus, G. R. J.; Köcher, C. Metal complexes of chiral imidazolin-2-ylidene ligands. Organometallics 1997, 16(11), 2472–2477.CrossRefGoogle Scholar
  31. 31.
    Herrmann, W. A.; Goossen, L. J.; Köcher, C.; Artus, G. R. J. Chiral heterocylic carbenes in asymmetric homogeneous catalysis. Angew. Chem. Int. Ed. 1996, 35(23), 2805–2807.CrossRefGoogle Scholar
  32. 32.
    Coudane, J.; Ustariz-Peyret, C.; Schwach, G.; Vert, M. More about the stereodependence of DD and LLpair linkages during the ring-opening polymerization of racemic lactide. J. Polym. Sci., Part A: Polym. Chem. 1997, 35(9), 1651–1658.CrossRefGoogle Scholar

Copyright information

© Chinese Chemical Society, Institute of Chemistry, Chinese Academy of Sciences and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Key Laboratory of Marine Materials and Related Technologies, Key Laboratory of Marine Materials and Protective Technologies of Zhejiang Province, Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingboChina
  2. 2.University of Chinese Academy of SciencesBeijingChina
  3. 3.State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina

Personalised recommendations