Binuclear complexes of rhodium or copper with pentamethylcyclopentadienyltricarbonyltungsten. Crystal structure of (η5-C5Me5)(CO)W(μ-CO)2Rh(PPh3)2

Article abstract of DOI:10.1016/0022-328X(94)05252-7

The reaction of Li*> (Cp^* = η⁵-C5Me5) with affords *(CO)W(μ-CO)2Rh(PPh3)2>, 3, which has been structurally characterised by an X-ray diffraction study, and shown to contain a short W-Rh bond of 2.5820(6) Angstroem and two semi-bridging CO ligands.Variable temperature 31P<1H> NMR spectra show that complex 3 is fluxional in solution and undergoes intramolecular interchange of inequivalent PPh3 with ΔG^<*> ca. 30 kJ mol^-1 at -105 deg C.Reaction of Li*> with gives the mono-triphenylphosphine complex *W(CO)3Cu(PPh3)>, 4a, which has the same valence electron count as 3 and has been characterised analytically and by IR and NMR spectroscopy.Evidence for a related molybdenum-copper species, 4b, is also presented.The structural and spectroscopic properties of new products are discussed in relation to those of related heterobinuclear compounds.Keywords: Rhodium; Copper; Tungsten; Carbonyl; Pentamethylcyclopentadienyl; Fluxionality