COBALT-PLATINUM CARBONYL-COMPLEXES WITH CARBIDO LIGANDS - CRYSTAL-STRUCTURE OF THE HEXANUCLEAR MIXED-METAL CLUSTER [CO3PT3(MU-H)(MU-6-C)(MU-CO)4(CO)5(PPRI3)3]

Reactions between the μ3-methylidyne tricobalt complex [Co3(μ3-CH)(CO)9] and the platinum reagents [Pt(C2H4)2(PR3)] (R = cyclo-C6H11 or Pri) in light petroleum at room temperature afford the mixed-metal carbido-carbonyl clusters [Co3Pt2(μ-H)(μ5-C)(μ-CO)2(CO)7(PR3)2] (R = cyclo-C6H11 or Pri) and [Co3Pt3(μ-H)(μ6-C)(μ-CO)4(CO)5(PPri3)3]. The structure of the latter has been established by an X-ray diffraction study. The carbido-carbon atom is located inside the Co3Pt3 core, with the metal atoms occupying essentially octahedral sites and with meridional arrangements of the Co3 and Pt3 groups. However, the core is open, since one Pt···Pt separation (3.260(1) Å) is too long for a direct metal-metal connectivity. The other Pt-Pt distance (2.868(1) Å) is such as to suggest that this vector is bridged by the hydrido ligand; a feature confirmed by the 1H NMR data. The three platinum atoms are ligated by PPri3 groups. Four of the Co-Pt vectors (2.599(2)-2.661(2) Å) are bridged by CO ligands, and a fifth (2.842(2) Å) is semi-bridged. The three non-bridged Co-Pt connectivities are longer (2.937(2)-3.060(2) Å). One cobalt atom carries two terminal CO groups and the other two cobalts are each coordinated by one such group. The NMR spectra (1H, 13C-{1H}, and 31P-{1H}) of the new cluster compounds are reported and discussed. © 1990.