Ruthenium‐Based NHC‐Arene Systems as Ring‐Opening Metathesis Polymerisation Catalysts

Abstract

Abstract The availability of starting materials, the complexity of the preparative routes and the cost to make the catalyst are key in the development of industrially relevant olefin metathesis catalysts. With this in mind, new synthetic routes, which lead to alternatives for the classic ruthenium benzylidene complexes and circumvent the need for patented Grubbs intermediates were explored. The research presented herein focuses on the coordination of “saturated” N‐heterocyclic carbene (NHC) ligands to Ru dimer [( p ‐cymene)RuCl 2 ] 2 . As the coordination of the standard NHC ligand H 2 IMes (1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene) was found to be unattainable, bidentate NHC analogues were synthesized instead. These are O ‐hydroxyaryl‐substituted NHCs, capable of binding with the metal centre through the oxygen atom as well as through the carbene carbon atom. Their chelating properties improved the stability of the corresponding ruthenium arene complexes, which allowed more successful isolation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)