Mixed-Metal Sulfido Clusters Containing Noble Metals and Group 15 Metals. Stepwise Construction of Bimetallic and Trimetallic Ru₂MS₂ (M = Sb, Bi), Ru₂PdSbS₂, and Ru₂Pd₂SbS₂ Cores

By starting from a diruthenium bis(μ-hydrosulfido) complex [(Cp°RuCl)2(μ-SH)2] (1; Cp° = η5-C5Me4Et), a series of new mixed-metal sulfur clusters containing both noble metals and group 15 metals have been synthesized. Thus, 1 was allowed to react with 1 equiv of MCl3 (M = Sb, Bi) to give the trinuclear Ru2M clusters [(Cp°RuCl)2(μ-SMCl2)(μ-SH)] (3a, M = Sb; 3b, M = Bi) containing bridging SH and SMCl2 ligands. Treatment of 3a with 1 equiv of [Pd(PPh3)4] at room temperature gave a mixture of the Ru−Pd−Sb clusters [(Cp°Ru)(Cp°RuCl)(μ-SSbCl2){PdCl(PPh3)}(μ3-S)(μ-H)] (4), [(Cp°Ru)2(SbCl2){Pd(PPh3)}2(μ3-S)2(μ-Cl)] (5), and [(Cp°Ru)(Cp°RuCl){PdCl(PPh3)}(SbCl)(μ3-S)2] (6). An analogous reaction carried out at −5 °C gave 4 as the major product. By contrast, isolation of the Bi analogues from the reaction of 3b and [Pd(PPh3)4] was unsuccessful. It was also confirmed that the isolated 4 was treated with 1 equiv of [Pd(PPh3)4] in THF either at 50 °C or at room temperature in the presence of triethylamine to give 5, while 4 was converted to 6 upon either warming to 50 °C or dehydrochlorination by the use of triethylamine in THF. Cluster 6 was readily transformed into 5 by treatment with [Pd(PPh3)4] in THF at room temperaure. Structures of the new clusters 3a, 3b, 4, 5, and 6 have been determined by single-crystal X-ray analysis.