source: e-Polymers year: 2003 number: P_018 doi: not available
Abstract: Stable nucleophilic N-heterocyclic carbenes (NHCs) are neutral, two-electron ligands with a negligible pi-back-bonding tendency. They behave as phosphine mimics, yet they are better sigma-donors and they form stronger bonds to metal centers than most phosphines. Their electronic and steric properties are liable to ample modification simply by varying the substituents on the nitrogen atoms. Therefore, NHCs constitute a promising new class of ligands available for catalyst engineering and fine-tuning. In this communication, we report on the synthesis of new ruthenium-arene complexes bearing NHC ligands - either preformed or generated in situ - and their use to promote the ring-opening metathesis polymerization (ROMP) of cyclooctene, a typical low-strain cyclic olefin.