IMIDO TRANSITION METAL COMPLEX METATHESIS CATALYSTS

An olefin metathesis catalyst system and process for the metathesis polymerization of cyclic olefins, such as dicyclopendatiene, an disclosed. The catalyst system comprises the reaction product of: (a) an imido transition metal halide complex of formula (I) wherein Ar is C6-20 aryl, preferably phenyl; M is a transition metal selected from the second and third rows of groups 5, 6, 7 and 8 of the Periodic Table and including for example niobium, tantalum, molybdenum, tungsten rhenium, ruthenium or osmium, preferably tungsten or molybdenum; R is independently halide, C1-20 alkyl, C1-12 alkoxy, C1-12 haloalkyl, C6-20 aryl, C6-20 aryloxy, cyano or combinations thereof; L is independently a complexing ligand selected from carbonyl, C1-12 alkoxy, C1-12 haloalkoxy C1-12 alkyl ethers, including C1-12 alkylnitriles, C5-20 pyridines, C3-36 tri(hydrocarbyl)phosphines, X is independently halide, x is 2 to 4; r is independently 0 to 5; 7 is 0 to 3, preferably 0 or 1; and x + y = 3, 4 or 5; and (b) a biphenol of formula (II) in which each Ar represents an aromatic ring-containing moiety having at least one hydroxyl group attached to an aromatic ring; each R is independently selected from C1 - 12 alkyl, aryl, halide, mono-, di or trihalo methyl, cyano and alkoxy or together form an alkylene; each n is independently 0-4; and m is independently 1-4; and the catalyst system further includes a co-catalyst.