Platinum-osmium cluster complexes from the addition of Pt(PBu3t) groups to Os3(CO)12

Three new compounds, PtOs3(CO)(12)(PBu3t) (10), Pt2Os3(CO)(12)(PBu3t)(2) (11), and Pt3Os3(CO)(12)(PBu3t)(3) (12), have been obtained from the reaction of Pt(PBu3t)(2) with Os-3(CO)(12) (9). The products were formed by the sequential addition of 1-3 Pt(PBu3t) groups to the three Os-Os bonds of the metal cluster of Os-3(CO)(12). In solution, compounds 10-12 interconvert among themselves by intermolecular exchange of the Pt(PBu3t) groups. When 11 is treated with PPh3, the mono- and bis(PPh3) derivatives of 9, Os-3(CO)(11)(PPh3) and Os-3(CO)(10)(PPh3)(2), were obtained by elimination of the Pt(PBu3t) groups together with one and two CO ligands, respectively. When heated, compound 11 was transformed into the new compound Pt2Os3(CO)(10)(PBu3t)((PBu2CMe2CH2)-C-t)(mu-H) (13) by the loss of two CO ligands and a metalation of one of the methyl groups of one of the PBu3t ligands. Compounds 10-13 have been characterized by single-crystal X-ray diffraction analyses.