New Carbide Clusters in the Cobalt Subgroup .17. Preparation and structural characterization of the mixed-metal octahedral Dianion [CO2RH4C(CO)13]2- AS ITS [PPH4]+ SALT

The title complex has been prepared by direct reaction of [Co3(CO)9CCl] with [PPh4][Rh(CO)4] in the molar ratio 1 :4 in tetrahydrofuran solution, and characterized by chemical and crystallographic methods. The anion belongs to the family of octahedral carbido-carbonyl clusters (86 valence electrons) with 13 ligands. The Co atoms are found to be contiguous with no trace of Co/Rh disorder. The ligand distribution differs from that of the analogous homometallic species [CO6C(CO)13]2- and [Rh6C(CO)13]2-. The factors controlling the ligand arrangements in the three species are discussed.