Oxidative Addition Reactions to Novel Heterotrinuclear Iridium Complexes with Mixed Bridging Ligands. Crystal Structure of [{Ir(.mu.-pz)(.mu.-StBu)I2(CO)[P(OMe)3]}2Pd

Abstract

The formation and properties of trinuclear heterobridged complexes of general formula [{Ir(μ-pz)(μ-StBu)L2}2Pd] [L2 = cycloocta-1,5-diene 1, (CO)2 2, (CO)[P(OMe)3] 3; pz = pyrazolate] are reported. Complex 3 reacts with methyl iodide or mercury(II) iodide to give compounds [{Ir2(μ-pz)2(μ-StBu) 2I(X)(CO)2[P(OMe)3]2}Pd] [X = Me (4) I (5)]. Compound 5 undergoes a further oxidative addition with I2 to form [{Ir(μ-pz)(μ-StBu)I2(CO)[P(OMe)3]} 2Pd], 6. Compound 6 can be also obtained by direct addition of iodine to complex 3 in a 2:1 molar ratio. The molecular structure of compound 6 has been determined by X-ray diffraction methods. The complex crystallizes in the triclinic system, space group P1, with a = 8.763(1) A, b = 12.023(2) A, c = 12.713(2) A, α = 102.086(6)°, β = 94.108(7)°, γ = 109.174(8)°, and Z = 1. Refinement by full-matrix least-squares techniques gave final R = 0.0322. Complex 6 is trinuclear with two octahedral IrI2(CO)[P(OMe)3] moieties symmetrically connected to a central square-planar Pd atom bridged through the nitrogens of a pyrazolate group and the S atom of a 2-methyl-2-propanethiolate ligand. © 1995 American Chemical Society.