Cyclohexadiene-linked clusters: synthesis and molecular structure of [{Os4(CO)8(MeCCMe)(η6-C6H6)}2(μ2-η2:η2-C6H8-1,3)]

The reaction of [Os4(CO)9(RCCR)(η6-C6H6)] (R=Me, Ph) with Me3NO in the presence of 1,3-cyclohexadiene or 1,4-cyclohexadiene yields the clusters [{Os4(CO)8(RCCR)(η6-C6H6)}2(μ2-η2:η2-C6H8-1,3)] and [{Os4(CO)8(RCCR)(η6-C6H6)}2(μ2-η2:η2-C6H8-1,4)], respectively. The molecular structure of [{Os4(CO)8(MeCCMe)(η6-C6H6)}2(μ2-η2:η2-C6H8-1,3)] has been determined by single crystal X-ray diffraction, and represents the first example of two osmium cluster fragments linked by 1,3-cyclohexadiene through a μ2-η2:η2-bridge.