Studies of metal exchange reactions: the synthesis and structures of heteronuclear metal clusters containing the indenyl ligand (μ3-CR)Co2M(CO)8(η5- Ind)(R=H,CH3,C6H5,COOC2H5; M=Mo,W)

The novel tetrahedral clusters (μ3-CR)Co2M(CO)8(η5-Ind) (M=Mo,W; R=H, CH3, C6H5, COOC2H5) 5–12 containing the indenyl ligand were isolated from reactions of tricobalt clusters (μ3-CR)Co3(CO)9 (R=H, CH3, C6H5, COOC2H5) and K(η5-Ind)M(CO)3 (M=Mo,W) under mild conditions. The cluster complex (μ3-CC6H5)CoMo2(CO)7(η5-Ind)(η5-Cp (Cp*=C5H4C(O)CH3) 16 was obtained via the stepwise metal exchange reaction of complex (μ3-CC6H5)Co2Mo(CO)8(η5-Ind) 9 with Na(η5-CpMo(CO)3, but the reaction of (μ3-CC6H5)Co2Mo(CO)8(η5-Cp*) 15 with K(η5-Ind)Mo(CO)3 yielded only 9. The crystal structures of compounds 7, 9 and 13 were established by single crystal X-ray diffraction methods and show structural evidence for “slippage” of the indenyl ring.