Efficient Exchange in a Bioinspired Dynamic Covalent Polymer Network via a Cyclic Phosphate Triester Intermediate

Soumabrata Majumdar; Brahim Mezari; Huiyi Zhang; Jeroen van Aart; Rolf A T M van Benthem; Johan P A Heuts; Rint P Sijbesma

doi:10.1021/acs.macromol.1c01504

Efficient Exchange in a Bioinspired Dynamic Covalent Polymer Network via a Cyclic Phosphate Triester Intermediate

Macromolecules. 2021 Sep 14;54(17):7955-7962. doi: 10.1021/acs.macromol.1c01504. Epub 2021 Aug 17.

Authors

Soumabrata Majumdar¹, Brahim Mezari², Huiyi Zhang¹, Jeroen van Aart³, Rolf A T M van Benthem^{3

4}, Johan P A Heuts¹, Rint P Sijbesma¹

Affiliations

¹ Department of Chemical Engineering & Chemistry and Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
² Department of Chemical Engineering & Chemistry, Laboratory of Inorganic Materials and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
³ Department of Chemical Engineering & Chemistry, Laboratory of Physical Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
⁴ DSM Materials Science Center, 6167 RD Geleen, The Netherlands.

Abstract

Bond exchange via neighboring group-assisted reactions in dynamic covalent networks results in efficient mechanical relaxation. In Nature, the high reactivity of RNA toward nucleophilic substitution is largely attributed to the formation of a cyclic phosphate ester intermediate via neighboring group participation. We took inspiration from RNA to develop a dynamic covalent network based on β-hydroxyl-mediated transesterifications of hydroxyethyl phosphate triesters. A simple one-step synthetic strategy provided a network containing phosphate triesters with a pendant hydroxyethyl group. ³¹P solid-state NMR demonstrated that a cyclic phosphate triester is an intermediate in transesterification, leading to dissociative network rearrangement. Significant viscous flow at 60-100 °C makes the material suitable for fast processing via extrusion and compression molding.