Harnessing non-covalent interactions synthesis & catalysis

Exploiting non-covalent interactions in polymerization catalysis: Highly active aluminum catalysts for ring-opening polymerization

Charles Romain 2 , Sami Gesslbauer 1 , R. Savela 2 , A. J. P. White 1 1 Imperial College London, UK, 2 Åbo Akademi University, Finland

There is a growing interest in harnessing non-covalent interactions (NCI) in metal catalysis to increase catalyst activity and selectivity.NCIs have largely been applied to catalytic organic reactions, 1 however, similar strategies are emerging in polymerization catalysis. 2 In olefin polymerisation, non-covalent attractive interactions have been proposed to explain the livingness of some post-metallocene catalysts. 3 In epoxide/CO 2 ring-opening copolymerization, electrostatic interactions between polymer chain end and the co-catalyst were found to improve catalyst selectivity. Finally, in cyclic ester ROP, NCIs between the growing polymer and the ligand were found to increase polymer tacticity. 3 Here, we report the benefit of hydrogen bond donors in the catalytic pocket to explain the high activity and stereoselectivity of a new family of aluminium catam complexes in cyclic ester ring-opening polymerization (Figure 1). 4 Structural characterization of the catalysts, mechanistic, kinetic (including isotope effects) and computational studies highlighting the benefit of such non-covalent interactions in ROP will be discussed (Figure 2).

Figure1:Lactide ROP using aluminum catalysts

Figure 2:Ligand-assisted monomer activation using “actor” ligands References 1. M. Raynal, P. Ballester, A. Vidal-Ferran and P. W. N. M. van Leeuwen, Chem. Soc. Rev., 2014, 43, 1660-1733; (b) J. Trouvé and R. Grammage-Doria,Chem. Soc. Rev., 2021,50, 3565-3584 2. C. Romain and S. Gesslbauer, Review under preparation; 3. C. Chen, Nat. Rev. Chem., 2018, 2, 6-14; (b) A. Iwashita, M. C. W. Chan, H. Makio and T. Fujita, Catal. Sci. Tech., 2014,4, 599-610; 4. S. Gesslbauer, H. Cheek, A. J. P. White and C. Romain, Dalton Trans., 2018, 47, 10410-10414; (b) S. Gesslbauer, R. Savela, Y. Chen, A. J. P. White and C. Romain, ACS Catal., 2019,9, 7912–7920; (c)S Gesslbauer, G.Hutchinson, A. J. P. White, J. Burés and C. Romain, ACS Catal., 2021, 11 4084-4093.

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© The Author(s), 2023

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