Synthesis, structure, and electrochemistry of the dicluster molecular pincer [Pt(3)(mu-PBu(t)(2))(3)(CO)(2)](2)(mu-1',1'''-diethynylbiferrocene).

The CuI catalyzed dehydro-halogenation of 1',1'''-diethynylbiferrocene and {Pt(3)}Cl [{Pt(3)} = Pt(3)(mu-PBu(t)(2))(3)(CO)(2)] (1:2 molar ratio) in diethylamine gives in high yields the bicluster derivative [{Pt(3)}CC-(eta(5)-C(5)H(4))Fe(eta(5)-C(5)H(4))](2), 3, in which two platinum triangles are connected by a diethynylbiferrocene spacer. In the structure of 3, confirmed by a diffractometric study, the two {Pt(3)} fragments lie, perfectly eclipsed, on the same side of the biferrocenyl moiety; this folded structure is also preferred in solution, as suggested by NMR Diffusion Ordered Spectroscopy (DOSY) and 1D Rotating-frame Overhauser Enhancement (ROE) measurements. Compound 3 exhibits a rich redox behavior, with a crowded sequence of six one-electron oxidation processes, the electrode potentials of which have been evaluated by digital simulations. On the basis of a spectroelectrochemical study, the first two oxidations are assigned to the iron centers of the diferrocenyl unit and the subsequent four electrons are removed from the {Pt(3)} units.