Synthesis, reactivity and structural characterization of some heterometallic complexes containing naked arsenic ligands†
Abstract
The reactions of [Co2(µ-As2)(CO)6] with [Mo2Cp2(CO)4] (Cp = η5-C5H5) and with [(OC)4CoMCp(CO)3] [M = Mo or W] gave, respectively, the known product [Mo2(µ-As2)Cp2(CO)4] 1 and the new heterobimetallic complexes [(OC)3Co(µ-As2)MCp(CO)2] [M = Mo 2 or W 3]. The mixed-metal complexes have been treated with PPh3 to give the substituted complexes [(Ph3P)(OC)2Co(µ-As2)MCp(CO)2] [M = Mo 4 or W 5]. Complex 2 reacted with [Cr(CO)5]·THF to give [(OC)3Co{µ-As2[Cr(CO)5]2}MoCp(CO)2] 6. Reaction of [MoWCp2(CO)4] with [Co2(µ-As2)(CO)6] does not lead to the complex [MoW(µ-As2)Cp2(CO)4] although this can be obtained by co-thermolysis of [Mo2Cp2(CO)6] and [W2Cp2(CO)6] with grey arsenic which affords three bimetallic products, [MM′(µ-As2)Cp2(CO)4] (M = M′ = Mo 1; M = Mo, M′ = W 7; M = M′ = W), and four trimetallic products, [M2M′(µ3-As)Cp3(CO)6] (M = M′ = Mo; M = Mo, M′ = W 8; M = W, M′ = Mo 9; M = M′ = W). The new heterometallic complexes 2, 3, 5, 6 and 9 have been characterized by X-ray diffraction analyses.