Alkyne-Substituted Carbonyl Clusters of Iridium: Synthesis, Characterization, and Solid-State Structures of Ir6(CO)13(μ-CO)(μ3-η2-PhCCPh) and Ir6(CO)13(μ3-η2-PhCCPh)2·CH2Cl2

The carbonyl cluster Ir6(CO)14(μ3-η2-PhCCPh) (1) is obtained by oxidation of [Ir6(CO)15]2- with the [Fe(C5H5)2]+ cation, in the presence of diphenylacetylene. Complex 1 crystallizes in the triclinic space group (No. 2) P1 with a = 9.443 (1) Å, b = 16.622 (1) Å, c = 21.560 (3) Å, α = 89.87 (1)°, β = 96.45 (1)°, γ = 101.78 (1)°, V = 3291 (1) Å3, and Z = 4; R = 0.034 for 6236 observed reflections having I ≥ σ3(I). When complex 1 is heated with excess of PhC=CPh, a further substitution occurs, yielding the carbonyl cluster Ir6(CO)12(μ3-η2-PhCCPh)2 (2). Crystals of 2 are monoclinic, space group C2/c (No. 15) with a = 10.751 (6) Å, b = 17.393 (7) Å, c = 23.240 (7) Å, β = 85.42 (4)°, V = 4332 (5) Å3, and Z = 4; R = 0.028 for 1645 observed reflections having I ≥ σ3(I). Both compounds contain an octahedron of iridium atoms, with the alkynyl units interacting with the faces of the metallic cores, in a μ3-η2 fashion. © 1992, American Chemical Society. All rights reserved.