Synthesis and characterisation of cis and trans isomers of the mixed chalcogen clusters Cp2Mo2Fe2(CO)8(μ3-S)(μ3-Se) and Cp2Mo2Fe2(CO)8(μ3-S)(μ3-Te)

The reaction of Fe2(CO)6(μ-SSe) and Cp2Mo2(CO)4 in benzene at room temperature for 2 h, yielded the new isomeric mixed-metal, mixed-dichalcogenide clusters trans-Cp2Mo2Fe2(CO)8(μ3-S)(μ3-Se) (1) and cis-Cp2Mo2Fe2(CO)8(μ3-S)(μ3-Se) (4). The new mixed-metal clusters 1 and 4 could also be obtained when Fe3(CO)9(μ3-S)(μ3-Se) and Cp2Mo2(CO)6 were heated at 65°C in benzene for 36 h. Similarly, the room-temperature reaction of Fe2(CO)6(μ-STe) with Cp2Mo2(CO)4 in benzene for 2 h and the thermolytic reaction of Fe3(CO)9(μ3-S)(μ3-Te) with Cp2Mo2(CO)6 in benzene for 36 h afforded the new isomeric clusters trans-Cp2Mo2Fe2(CO)8(μ3-S)(μ3-Te) (9) and cis-Cp2Mo2Fe2(CO)8(μ3-S)(μ3-Te) (11). The new clusters have been characterised by IR and by 1H-, 77Se-, 125Te-NMR spectroscopy. Clusters 1 and 4 have also been structurally characterised by single-crystal X-ray diffraction methods.© Elsevie