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)

Abstract

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.