Activity of a new class of ruthenium based ring-closing metathesis and ring-opening metathesis polymerization catalysts coordinated with a 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene and a Schiff base ligand

A new class of ruthenium based catalysts coordinated with a 1,3-dimesityl-4.5-diliydroimidazol-2-ylidene and a Schiff base ligand have been tested in ring-closing metathesis and ring-opening metathesis polymerization reactions. The results obtained point out that the synergy of Schiff base ligands with a strong Lewis basic N-heterocyclic carbene ligand lead to mixed ligand catalytic systems that combine very high activity with excellent stability. Furthermore, the catalytic activity of these catalysts is very dependent on the steric and electronic environment of the Schiff base. (C) 2002 Elsevier Science Ltd. All rights reserved.