Lactide polymerisation by ring-expanded NHC complexes of zinc

The reaction of the ring-expanded N-heterocyclic carbenes (RE-NHCs) with [ZnMe2] affords the structurally characterised complexes [(6-Mes)ZnMe2] (1) and [(7-Mes)ZnMe2] (2). The activity of the two complexes, along with that of the free carbenes, for the ring-opening polymerisation of rac-lactide has been probed. Even for such strongly σ-donating carbenes, dissociation from the metal centre cannot be ruled out.

The activity of ring-expanded N-heterocyclic carbene complexes of zinc for the ring-opening polymerisation of rac-lactide has been probed alongside that of the free carbenes.Figure optionsDownload as PowerPoint slide