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The digold-tetrarhenium cluster Re4(AuPPh3)2(CO)12(μ3-C≡CFc)2 (1) was obtained by the thermolysis of known complex Re2(AuPPh3)(CO)8(μ-C≡CFc) (2) and fully characterized by a single crystal X-ray diffraction study. Cluster 1 has a butterfly Re4 geometry, and both Re3 wings are capped with AuPPh3 groups. Two ferrocenylethynyl ligands symmetrically coordinated within cavity of the wings. The dihedral angle between the Re3 wings is rather narrow, 73.2°, whereas the 64e butterfly clusters usually have a more flattened structure. An examination of the carbonyl region of the 13C NMR of 1 and 2 revealed that 1 is stereochemically rigid while 2 is fluxional with respect to a σ-π interconversion of the ferrocenyl ethynyl group across the Re−Re edge of the Re2Au triangle. Complex 1 revealed a very rare electronic communication between the ferrocene units across the cluster core. According to the cyclic voltammetric (CV) data, cluster 1 undergoes two reversible redox process with ferrocene oxidations separated by 109...

Reactions of acetylide clusters M3H(C⋮CFc)(CO)9 (1a, M = Ru; 1b, M = Os; Fc = ferrocenyl) with Ru3(CO)12 in refluxing hexane yield the tetranuclear clusters RuM3H(C⋮CFc)(CO)12 (2a,b) with a butterfly metal core. The μ4-acetylide ligand of these complexes undergoes migration, indicated by variable-temperature 1H and 13C NMR studies. Compounds 2a and 2b are relatively unstable in solution as well as in the solid state and decompose with formation of corresponding trinuclear acetylide precursors and Ru3(CO)12. The molecular structures of 1a and 2a were established by the X-ray diffraction study of a mixed crystal, which contains both clusters in a 1:1 ratio.

International audience; Palladium P,C,P pincer complexes based on ferrocene were synthesized for the first time. The reaction of the 1,3-bis((dialkylphosphino)methyl)ferrocenes {1,3-(R2PCH2)2C5H3}Fe(C5H5) (2a, R = Pri; 2b, R = But) with PdCl2(NCPh)2 in refluxing 2-methoxyethanol leads to the corresponding pincer complexes PdCl[{2,5-(R2PCH2)2C5H2}Fe(C5H5)] (3a,b). The ferrocene-based binuclear compound 3b reacts with [Cp2Fe]PF6 to form the ferrocenium-based pincer complex {PdCl[{2,5-(But2PCH2)2C5H2}Fe(C5H5)]}PF6 (4b), and this is the first example of ferrocene-based phosphine chelate oxidation centered on the iron atom. Treatment of complexes 3a,b with NaBH4 in refluxing ethanol affords the complexes Pd(BH4)[{2,5-(R2PCH2)2C5H2}Fe(C5H5)] (5a, R = Pri; 5b, R = But), containing a BH4− group coordinated to the metal in the rarely occurring unidentate mode. The structures of 3a,b and 5b were confirmed by X-ray analyses. Cyclic voltammetric investigations of complexes 2b and 3a,b are also reported. The structural and spectroscopic features of the palladium ferrocene-based pincer complexes are discussed and compared with those of related compounds.