Exploring the Reactivity of Na[W2(μ-Cl)3Cl4(THF)2]∙(THF)3 towards the Polymerization of Selected Cycloolefins.

The bimetallic compound Na[W2(μ-Cl)3Cl4(THF)2]·(THF)₃ (1, {W (3) W}(6+), a'2e'4) is a highly efficient room-temperature initiator for ring opening metathesis polymerization (ROMP) of norbornene (NBE) and some of its derivatives. In most cases, addition of phenylacetylene (PA) as co-initiator improves the catalytic activity and retains the high cis-stereoselectivity. On the other hand, 1 can polymerize cyclopentadiene (CPD), not via a metathetic, but rather, via a cationic mechanism.