Synthesis and characterization of organotransition metal double μ3-RCCo2M (M=Mo, W) cluster complexes containing bridged dicyclopentadienyl ligands. Crystal structure of [μ3-MeCCo2Mo(CO)8]2 [η5-C5H4C(O) CH2]2

While the succinyl-bridged dicyclopentadienyl M/Na salts [η5-C5H4C(O)CH2]2[M(CO)3Na]2, prepared from [η5-C5H4C(O)CH2]2Na2 and M(CO)6 (M=Mo, W), react with single clusters μ3-RCCo3(CO)9 (2, R=Me, Ph) to give the succinyl-bridged dicyclopentadienyl-bridged double clusters [μ3-RCCo2M(CO)8]2[η5-C5H4C(O)CH2]2 (3a–d, M=Mo, W; R=Me, Ph), the ether chain-bridged dicyclopentadienyl M/Na salts [η5-C5H4CH2(CH2OCH2)3CH2C5H4-η5][M(CO)3Na]2, generated from [η5-C5H4CH2(CH2OCH2)3CH2C5H4-η5]Na2 and M(CO)6 (M=Mo, W), react with single clusters 2 to afford the ether chain-bridged dicyclopentadienyl-bridged double clusters [μ3-RCCo2M(CO)8]2[η5-C5H4CH2(CH2OCH2)3CH2C5H4-η5] (5a–d, M=Mo, W; R=Me, Ph). Further treatment of 3a, b (M=Mo, W; R=Me) with NaBH4 has been shown to give the corresponding dihydroxy carbon chain-bridged dicyclopentadienyl-bridged double clusters [μ3-MeCCo2M(CO)8]2[η5-C5H4CH(OH)CH2]2 (6a, b, M=Mo, W). All the new clusters 3a–d, 5a–d and 6a, b have been characterized by elemental analysis, IR and 1H-NMR spectroscopy, as well as by X-ray diffraction techniques for 3a (M=Mo, R=Me).