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Abstract
Reactions of Mo(CO)6 with Na2WO4 · 2H2O in refluxing carboxylic anhydride produce the triangular bioxo-capped mixed-metal carboxylate clusters Na[MoW2O2(O2CR)9] (R = Me, 1; Et, 2), the propionate being hydrolyzed in 2M HCl containing ZnCl2 to form [MoW2O2(O2CEt)6(H2O)3]ZnCl4·2H2O (3). Cluster 2 is converted to the incomplete cuboidal tetraanion [MoW2O4(O2CEt)8]4- upon reacting with Cr(CO)6 in propionic anhydride at 120°, the latter species being trapped by Cr3± and Na± ions in the reaction mixture to afford the octanuclear heterometallic chain-like cluster Na2Cr2 [MoW2O4(O2CEt)8]2 (4). Clusters 1, 3 and 4 have been characterized by X-ray crystallography with the following crystal data, for 1: monoclinic, space group P21/c, a = 16.666(8), b = 11.096(3), c = 16.541(7) Å, β = 94.60(4)°, V = 3048.9 Å3, Z = 4, R, Rw = 0.070, 0.079; for 3, monoclinic, space group Cm, a = 10.259(3), b = 15.756(3), c = 10.870(3) Å, β = 96.18(3)°, V = 1746.8 Å3, Z = 2, R, Rw = 0.028, 0.034; for 4, triclinic, space group P-1, a = 13.013(5), b = 14.005(4), c = 12.357(4) Å, α = 109.71(2), β = 117.77(3), γ = 90.41(3)°, V = 1838.9 Å3, Z = 1, R, Rw = 0.037, 0.042.