Metathesis polymerization of norbornene and terminal acetylenes catalyzed by bis(acetonitrile) complexes of molybdenum and tungsten

The ring-opening metathesis polymerization (ROMP) of norbornene catalyzed by bis(acetonitrile) complexes of molybdenum and tungsten, [M(η3-C3H5)Cl(CO)2(NCMe)2], has been investigated. The poly(norbornene) obtained from this system shows a significantly high cis content. These complexes also catalyze the polymerization of terminal acetylenes. A highly active catalytic system for the ROMP of norbornene was achieved by the activation of the tungsten complex with one equivalent of phenylacetylene, and the high cis selectivity of the resulting poly(norbornene) was maintained.