SYNTHESIS AND SOLID-STATE STRUCTURE OF [PD6RU6(CO)24]2- - ELECTROCHEMISTRY AND C-13 NUCLEAR-MAGNETIC-RESONANCE SPECTRA OF [FE6PD6H(CO)24]3- AND [PD6RU6(CO)24]2-

The cluster [Pd6Ru6(CO)24]2- was obtained in good yield from the reaction of [Ru3H(CO)11]- with [Pd(NCPh)2Cl2]. The salt [NEt4]2[Pd6Ru6(CO)24] crystallized in the triclinic space group P1BAR (no. 2) with a = 11.514(5), b = 11.602(5), c = 11.933(5) angstrom, alpha = 73.01(3), beta = 78.25(3), gamma = 65.26(4)-degrees, Z = 1. Data were collected at room temperature, giving 5968 unique reflections. The structure was solved by direct methods. The final discrepancy indices were R = 0.024 and R' = 0.026 for 4129 independent reflections with I > 3sigma(I). The metal skeleton consists of a trigonally distorted octahedron of palladium atoms, capped by six ruthenium atoms with twelve terminal, six edge- and six face-bridging carbonyl ligands. This ruthenium-palladium cluster adopts the same metallic polyhedron as [Fe6Pd6H(CO)24]3- but possesses two valence electrons less. The solution C-13 NMR spectra of both anions are in agreement with the solid-state structures and electrochemical analysis shows that they produce labile congeners: [Pd6Ru6(CO)24]2- undergoes a one-electron oxidation with formation of the relatively stable monoanion; [Fe6Pd6H(CO)24]3- can be oxidized and reduced, to give corresponding anions with charges of 2- to 5-.