Silane-induced ring-opening polymerization of 1,1,3,3-tetramethyl-2-oxa-1,3-disilacyclopentane catalyzed by a triruthenium cluster

The silane-induced ring-opening polymerization of a cyclic siloxane, 1,1,3,3-tetramethyl-2-oxa-1,3-disilacyclopentane (2), is catalyzed by a ruthenium cluster, (μ3,η2:η3:η5-acenapthylene)Ru3(CO)7 (1), to give poly(tetramethylsilethylenesiloxane) with Mn=6300–780,000 and Mw/Mn=1.5–3.0. The molecular weight of the polymer can be controlled by changing the concentration of the monomer solution. Addition of acetone results in formation of the polymer with Mn=4400, spectroscopic analysis of which reveals existence of a siloxy and an isopropoxy moieties at the end group.