Involvement of Multiply Bonded Dirhenium Complexes in Mixed-Metal Assemblies. Isolation and Characterization of a New Type of Re₄Pd₂ Cluster

The Re−Clt bond that is cis to the μ-CO unit in the edge-sharing bioctahedral complex Re2(μ-Cl)(μ-CO)(μ-dppE)2Cl3(CO) (1b; dppE = Ph2PC(CH2)PPh2) is labile toward substitution by anionic and neutral thiocyanate and cyanide containing metal fragments to afford mixed-metal Re4Pd2, Re2W, and Re2Pt assemblies. These products (3−5) retain the ReRe bond of the parent dirhenium(II) complex as demonstrated by the crystal structure of the Re4Pd2 cluster [Re2(μ-Cl)(μ-CO)(μ-dppE)2Cl2(CO)]2(μ-NCS)2[Pd2(μ-SCN)(μ-NCS)Cl2].