Synthesis, reactivity and structural characterization of some heterometallic complexes containing naked arsenic ligands

摘要

The reactions of [Co(μ-As_2)(CO)_6] with [Mo_2Cp_2(CO)_4](Cp=#eta#~5-C_5H_5) and with [(OC)_4CoMCp(CO)_3][M = Mo or W] gave, respectively, the known product [Mo_2(μ-As_2)Cp_2(CO)_4] 1 and the new heterobimetallic complexes [(OC)_3Co(μ-As_2)MCp(CO)_2][M = Mo 2 or W 3]. The mixed-metal complexes have been treated with PPh_3 to give the substituted complexes [(Ph_3P)(OC)_2Co(μ-As_2)MCp(CO)_2][M = Mo 4 or W 5]. Complex 2 reacted with [Cr(CO)_5]. THF to give [(OC)_3Co{μ-As_2[Cr(CO)_5]_2}MoCp(CO)_2] 6. Reaction of {MoWCp_2(CO)_4] with [Co_2(μ-As_2)-(CO)_6] does not lead to the compex [MoW(μ-As_2)Cp_2(CO)_4]although this can be obtained by co-thermolysis of [Mo_2Cp_2(CO)_6] and [W_2Cp_2(CO)_6] with grey arsenic which affords three bimetallic products, [MM′(μ-As_2)-Cp_2(CO)_4](M = M′= Mo 1; M = Mo, M′= W 7; M = M′= W), and four trimetallic products, [M_2M′(μ_3-As)-Cp_3(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.