Thermolysis of Fe3(CO)9(μ3-Se)(μ3-E) (E = S, Te) with Cp2Mo2(CO)6 and formation of new mixed-chalcogenide, mixed Fe-Mo carbonyl clusters. Crystal structures of Cp2Mo2Fe2(CO)6(μ3-Se)2(μ4-Te), Cp2Mo2Fe2(CO)7(μ3-Se)(μ3-Te) and Cp2Mo2Fe2(CO)6(μ3-S)(μ3-Se)(μ4-Se)

Abstract

Abstract The thermolytic reaction of Fe3(CO)9(μ3-Se)(μ3-Te) with Cp2Mo2(CO)6 in benzene yielded the new mixed-metal, mixed trichalcogenide clusters Cp2Mo2Fe2(CO)6(μ3-Se)(μ3-Te)(μ4-Te) (2a), Cp2Mo2Fe2(CO)6(μ3-Te)2(μ4-Se) (2b) and Cp2Mo2Fe2(CO)6(μ3-Se)2(μ4-Te) (3a), Cp2Mo2Fe2(CO)6(μ3-Se)(μ3-Te)(μ4-Se) (3b) as well as the dichalcogenide cluster Cp2Mo2Fe2(CO)7(μ3-Se)(μ3-Te) (8). Similarly, the thermolysis of Fe3(CO)9(μ3-S)(μ3-Se) with Cp2Mo2(CO)6 in benzene afforded the new mixed-metal, mixed trichalcogenide clusters Cp2Mo2Fe2(CO)6(μ3-S)2(μ4-Se) (10), Cp2Mo2Fe2(CO)6(μ3-S)(μ3-Se)(μ4-Se) (11) and the dichalcogenide cluster Cp2Mo2Fe2(CO)7(μ3-S)(μ3-Se) (13). In the case of 10 and 11, formation of isomers containing the sulphido in the μ4-site was not observed. Compounds 2a and 2b could also be obtained when Cp2Mo2Fe2(CO)6(μ3-Te)2 was refluxed with selenium powder in benzene. Similarly, refluxing of benzene solutions containing selenium powder and Cp2Mo2Fe2(CO)6(μ3-Se)(μ3-Te) formed 3a and 3b, and sulphur powder with Cp2Mo2Fe2(CO)6(μ3-S)(μ3-Se) or Cp2Mo2Fe2(CO)6(μ3-Se)2 yielded the compounds 10 and 11 respectively. The new clusters have been characterised by IR and by 1H, 13C, 77Se and 125Te NMR spectroscopy. Clusters 3a, 8 and 11 have also been structurally characterised by single-crystal X-ray diffraction methods.