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 [eta(5)-C5H4C(O)CH2](2)[M(CO)(3)Na](2), prepared from [eta(5)- C5H4C(O)CH2](2)Na-2 and M(CO)(6) (M = Mo, W), react with single clusters mu(3)-RCCo3(CO)(9) (2, R = Me, Ph) to give the succinyl-bridged dicyclopentadienyl-bridged double clusters [mu(3)-RCCo2M(CO)(8)](2)[eta(5)-C5H4C(O)CH2](2) (3a-d, M = Mo, W; R = Me, Ph), the ether chain-bridged dicyclopentadienyl M/Na salts [eta(5)-C5H4CH2(CH2OCH2)(3)CH2C5H4-eta(5)][M(CO)(3)Na](2), generated from [eta(5)-C5H4CH2(CH2OCH2)(3)CH2C5H4-eta(5)]-Na-2 and M(CO)(6) (M = MO, W), react with single clusters 2 to afford the ether chain-bridged dicyclopentadienyl-bridged double clusters [mu(3)-RCCo2M(CO)(8)](2)[eta(5)-C-5 H4CH2(CH2OCH2)(3)CH2C5H4-eta(5)] (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 [mu(3)-MeCCo2M(CO)(8)](2)[eta(5)-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 H-1-NMR spectroscopy, as well as by X-ray diffraction techniques for 3a (M = Me, R = Me). (C) 2002 Elsevier Science B.V. All rights reserved.