Selective CO oxidation of heterometallic carbonyl clusters with the oxygen transfer reagent (p-CH3OC6H4)2TeO. Crystal structures of (μ3-S)FeCoMo(CO)7(η5-C5H4COCH3)(PPh3) and (μ3-Se)FeCoMo(CO)7(η5-C5H4COCH3)(PPh3)

The oxygen transfer reaction of the heterometallic carbonyl cluster (μ3-S)FeCo2(CO)9 with bis(p-methoxyphenyl)telluroxide (BMPTO) gives bis(p-methoxyphenyl)telluride (BMPT) coordinated metal cluster products (μ3-S)FeCo2(CO)8(BMPT) (1a) and (μ3-S)FeCo2(CO)7(BMPT)2 (1b), which react further with PPh3 to afford Ph3P-substituted derivatives (μ3-S)FeCo2(CO)8(PPh3) (1c) and (μ3-S)FeCo2(CO)7(PPh3)2 (1d), respectively. Similarly, the reactions of heterometallic clusters (μ3-S)FeCoM(CO)8(η5-C5H4R) or (μ3-Se)FeCoM(CO)8(η5-C5H4R) with BMPTO afford (μ3-S)FeCoM(CO)7(η5-C5H4R)(BMPT) (2a, M=Mo, R=H; 2b, M=Mo, R=COCH3; 2c, M=Mo, R=CO2CH3; 2d, M=Mo, R=C(CH3)NNHC6H3(NO2)2-2,4; 2e, M=W, R=H; 2f, M=W, R=COCH3) and (μ3-Se)FeCoM(CO)7(η5-C5H4R)(BMPT) (2g, M=Mo, R=COCH3; 2h, M=W, R=C(CH3)NNHC6H3(NO2)2-2,4), whereas 2a–2d and 2g react with PPh3 to produce (μ3-S)FeCoMo(CO)7(η5-C5H4R)(PPh3) (3a, R=H; 3b, R=COCH3; 3c, R=CO2CH3; 3d, R=C(CH3)NNHC6H3(NO2)2-2,4) and (μ3-Se)FeCoMo(CO)7(η5-C5H4COCH3)(PPh3) (3e). The products have been characterized by elemental analyses, IR, 1H-NMR 125Te-NMR and FAB-MS spectroscopies. The X-ray diffraction analyses for 3b and 3e have not only confirmed their structures, but also proved such oxygen transfer reactions to be highly selective towards Co atoms in those heterometallic carbonyl cluster substrates.