Similarities and Contrasts between Silyl and Stannyl Derivatives of Ruthenium and Osmium

Abstract

Silyl and stannyl complexes of ruthenium and osmium bearing halogen substituents on the silicon and tin atoms undergo many interesting reactions. While there are formal similarities, there are also marked differences between these silyl and stannyl derivatives. This review first surveys the synthetic approaches we have developed to the silyl and stannyl complexes that involve oxidative addition of halogenated silanes coupled with reductive elimination for the preparation of the silyl complexes LnM(SiRnX3-n) (M = Ru, Os) and reaction between LnMH and the vinylstannane R3SnCHCH2 to give first the triorganostannyl complexes LnM(SnR3) (M = Ru, Os), which are then functionalized by redistribution reactions to give LnM(SnRnX3-n) (M = Ru, Os). Among the unusual compounds derived from these halogenated silyl and stannyl complexes are derivatives with the following novel ligands: Si(OH)3, Sn(OH)3, silatranyl, stannatranyl, SnH3, and SnMe2SnPh3. A contrast between the osmasilanol LnOs(SiMe2OH) and the osmastannol LnOs(SnMe2OH) is that the former deprotonates to a silanolate anion, [LnOs(SiMe2O)]-, while the latter, when treated with base, ortho-stannylates a triphenylphosphine ligand. Another contrast is provided by the ease with which osmium trimethylstannyl complexes undergo α-methyl migration reactions.