Azolium hydrogen carbonates and azolium carboxylates as organic pre-catalysts for N-heterocyclic carbene-catalysed group transfer and ring-opening polymerisations

Abstract : Various imidazolium-2-carboxylates and (benz) imidazolium hydrogen carbonates, denoted as NHC-CO2 adducts and [NHC(H)][HCO3], respectively, were employed as masked N-heterocyclic carbenes (NHCs) to bring about both the ring opening polymerisation (ROP) of D, L-lactide (LA) and the group transfer polymerisation (GTP) of methyl methacrylate (MMA). Polymerisation reactions could be performed at room temperature by generation of related free NHCs by a simple solvation effect. Catalytic efficiencies of imidazolium-2-carboxylates were found to be approximately three times higher than that of their hydrogen carbonate counterparts for the ROP of D, L-LA, except in the particular case of 1,3-dicyclohexylbenzimidazolium hydrogen carbonate that exhibited a similar catalytic performance to that of NHC-CO2 adducts. The catalytic efficiencies of free NHCs and NHC precursors were thus in the following order: [NHC(H)][HCO3] < NHC-CO2 adducts << free NHCs. Only NHC-CO2 adducts allowed the catalysis of the GTP of MMA in bulk in a controlled manner, [NHC(H)][HCO3] precursor salts being poorly soluble in the monomer substrate, causing a loss of control of GTP under solvent-less conditions.
Document type :
Journal articles
Complete list of metadatas

https://hal.archives-ouvertes.fr/hal-00930998
Contributor : Dominique Richard <>
Submitted on : Tuesday, January 14, 2014 - 5:31:10 PM
Last modification on : Thursday, January 11, 2018 - 6:28:09 AM

Identifiers

Collections

Citation

Maréva Fèvre, Joan Vignolle, Daniel Taton. Azolium hydrogen carbonates and azolium carboxylates as organic pre-catalysts for N-heterocyclic carbene-catalysed group transfer and ring-opening polymerisations. Polymer Chemistry, Royal Society of Chemistry - RSC, 2013, 4 (6), pp.1995-2003. ⟨10.1039/c2py20915b⟩. ⟨hal-00930998⟩

Share

Metrics

Record views

128