Iridium–Ruthenium–gold cluster complexes: Structures, and skeletal Rearrangements

Three new IrRuAu trimetallic cluster complexes: IrRu3(CO)13AuPPh3, 1, HIrRu3(CO)12(AuPPh3)2, 2 and IrRu3(CO)12(AuPPh3)3, 3 were obtained in low yields from the reaction of HIrRu3(CO)13 with [(AuPPh3)3O][BF4]. Compounds 1 and 3 were subsequently obtained in much better yields (82%) and (84%) from the reactions of [AuPPh3][NO3] and [(AuPPh3)3O][BF4] with [PPN][IrRu3(CO)13], respectively. The molecular structures of all three compounds were established by single crystal x-ray diffraction methods. Compounds 1 and 2 contain an Au(PPh3) group that bridges one triangular face of a tetrahedral IrRu3 cluster. Compound 2 contains a second Au(PPh3) capping group that bridges an Ir–Ru–Au triangle. Compound 3 consists of a pentagonal bipyramidal Au3IrRu3 cluster that has three gold atoms and two of the ruthenium atoms in the equatorial plane. There is a bond between the apical Ir and Ru atoms. Compounds 2 and 3 exhibit dynamical activity in the metal skeleton that leads to a rapid averaging of the inequivalent Au(PPh3) groups on the NMR timescale at room temperature.