Ring-Expansion Metathesis Polymerization under Confinement

• DOI: 10.1021/jacs.4c18171
• Publication Date: 2025-02-26T15:13:57Z
• Authors: Patrick Probst; Moritz Lindemann; Johanna R. Bruckner; Boshra Atwi; Dongren Wang; Felix R. Fischer; Marc Högler; Matthias Bauer; Niels Hansen; Michael Dyballa; Michael R. Buchme...
• Keywords: Ring-opening metathesis polymerisation

The cationic molybdenum alkylidyne N-heterocyclic carbene (NHC) complex [Mo(C-p-OMeC6H4)(OCMe(CF3)2)2 (IMes)][B(ArF4] (IMes = 1,3-dimesitylimidazol-2-ylidene) was selectively immobilized inside the pores of ordered mesoporous silica (OMS) with pore diameters 66, 56, and 28 Å used in ring-expansion metathesis polymerization (REMP) cyclic olefins to yield polymers. A strong confinement effect observed for cis-cyclooctene (cCOE), 1,5-cyclooctadiene (COD), (+)-2,3-endo,exo-dicarbomethoxynorborn-5-ene ((+)-DCMNBE), 2-methyl-2-phenylcycloprop-1-ene (MPCP), allowing synthesis low-molecular-weight polymers even at a high monomer concentration. exclusive formation demonstrated by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. Confinement also influences stereoselectivity, resulting pronounced increase Z-selectivity an increased cis-syndiospecificity.