Highly Efficient Catalytic Reactions via Activation of a Si—H Bond of Organohydrosilanes by Triruthenium Carbonyl Clusters Bearing Bridging an Acenaphthylene or Azulene Ligand

Abstract

Highly efficient catalytic reactions have been achieved via activation of Si-H bonds of organohydrosilanes by triruthenium carbonyl clusters bearing bridging acenaphthylene or azulene ligands. A ruthenium complex, (μ2, η2:η3:η5-acenaphthylene) Ru3 (CO)7 (1) catalyzes hydrosilylation of ketones and aldehydes in solution at room temperature to form the corresponding silyl ether in high yields. Prior activation of the catalyst by excess amounts of the hydrosilane results in dramatic increase of the catalytic activity. Application of the hydrosilylation catalyzed by preactivated 1 to the reduction of carboxylic acids and their derivatives has provided efficient preparative methods for silyl and alkyl ethers from esters, silyl ethers from carboxylic acids, and amines from amides, which are hardly achieved with other transition metal catalysts. The cluster 1 also behaves as an active catalyst for ring-opening polymerization of cyclic ethers and cyclic siloxanes and addition polymerization of vinyl ethers, which are induced by hydrosilanes. Spectroscopic analysis of the polymers obtained reveals existence of an organosilyl moiety at the end group, which is useful for further chemical transformation of the formed polymer. Isolation, characterization, and reactions of possible catalytically active species help discussion on the reaction mechanisms, in which a triruthenium hydridosilyl cluster is involved in the catalytic cycle.