The ditertiary-phosphane-bridged heteronuclear cluster RuOs 3(μ-H)2(CO)9(μ-CO)2(μ-dppm) : Synthesis and reactivity with alkynes

Abstract

A high-yielding alternative synthesis of the dppm-bridged heteronuclear cluster RuOs3(μ-H)2(CO)9(μ-CO) 2(μ-dppm) (1) [dppm = bis(diphenylphosphanyl)methane] has been developed. Thermolysis of 1 resulted in dephenylation of both phosphane groups to afford the butterfly cluster RuOs3(CO)12(μ 4,κ2:κ2-PhPCH2PPh) (2). The reaction of 1 with selected alkynes afforded the products RuOs 3(μ-H)(CO)8(μCO)(μ3, κ2:κ1-PhPCH2PPh2) (μ3η1:η2:η1-L) (3) (L = alkyne) in which the alkyne is aligned parallel to an Os-Os bond (// Os-Os isomer). The clusters incorporating internal alkynes underwent isomerization to the //Ru-Os isomer by alkyne and hydride migration. Several other cluster products of these reactions were also identified, including RuOs 3(μ-H)-(CO)8(μ-CO)(μ3, κ2:K1-PhPCH2PPh2) (μ3,η1:η2:η1- tBuC2CHO) (6) in which the methyl group of the alkyne has been oxidized to an aldehyde. © Wiley-VCH Verlag GmbH & Co. KGaA, 2007.