Trinuclear ReFePt clusters with a μ 3 -phenylvinylidene ligand: synthetic approaches, rearrangement of vinylidene, and redox-induced transformations.

A series of trinuclear μ 3 -vinylidene ReFePt clusters were synthesized by the application of two approaches: (i) reactions of the binuclear RePt μ-vinylidene complexes with Fe 2 (CO) 9 ; (ii) ligand substitution or exchange reactions at the Pt atom in the synthesized ReFePt clusters. The molecular structures of CpReFePt(μ 3 -CCHPh)(CO) 5 [P(OEt) 3 ]L [L = CO; P(OEt) 3 ] were determined by an X-ray diffraction study. The obtained compounds were studied by IR and 1 H, 13 C and 31 P NMR spectroscopy. The spectroscopic study revealed that the clusters CpReFePt(μ 3 -CCHPh)(CO) 5 [P(OEt) 3 ]L [L = CO; P(OEt) 3 ] and CpReFePt(μ 3 -CCHPh)(CO) 6 [P(OPr i ) 3 ] undergo isomerization upon dissolution, resulting in three isomers with different positions of the μ 3 -vinylidene ligand over the ReFePt core. The redox properties of the clusters were studied by electrochemical methods. The relatively stable cation-radicals obtained by chemical oxidation of CpReFePt(μ 3 -CCHPh)(CO) 6 [P(OPr i ) 3 ] and CpReFePt(μ 3 -CCHPh)(CO) 5 [P(OEt) 3 ] 2 with ferrocenium tetrafluoroborate were characterized by EPR spectroscopy.