Mixed Ruthenium-Iridium Carbonyl Cluster Complexes. Synthesis of the Anions [Ru3Ir2(CO)14]2- and [Ru3Ir2(CO)14H]- and Crystal Structures of Their [tetraphenylphosphonium]+ Salts

The reaction of Ru3(CO)12 and [Ir(CO)4]- (as [PPh4]+ or [N(PPh3)2]+ salts) yields the anion [Ru3Ir2(CO)14]2- (1) which has been found to derive from the intermediate [Ru3Ir(CO)13]- anion. Treatment of (1) with acids gives the conjugated hydrido species [Ru3Ir2(CO)14H]- (2). The two anions were characterized by single-crystal X-ray diffraction of their [ PPh4]+ salts. [PPh4]2[Ru3Ir2(CO)14]: space group C2/c, Z = 4, a = 22.121(5) Å, b = 10.546(5) Å, c = 25.931(5) Å, β = 103.870(5)°, R = 0.052 and Rw = 0.130 for 3128 independent reflections with I > 2σ(I). [PPh4][Ru3Ir2(CO)14H]: space group P21/c, Z = 8, a = 22.833(5) Å, b = 13.893(5) Å, c = 25.810(5) Å, β = 92.650(5)°, R = 0.070 and Rw = 0.150 for 12141 independent reflections with I > 2σ(I). Both anions 1 and 2 have a trigonal bipyramidal metal frame. There are two independent anions in the asymmetric unit of 2 differing in their ligand stereochemistry.