Exploring the Reactivity of NaW2(μ-Cl)3Cl4(THF)2∙(THF)3 towards the Polymerization of Selected Cycloolefins

摘要

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. Here, we present a comparison of the reactivity of the two catalytic systems (>1 and >1/>PA) between themselves and with other systems reported in the literature, the characterization of the polymers formed and mechanistic aspects of the corresponding reactions.