Study of the Coordination Modes of Hybrid NNCp Cyclopentadienyl/Scorpionate Ligands in Ir Compounds.

A new coordination mode for the hybrid scorpionate/cyclopentadienyl ligand bpzcp, [bpzcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethylcyclopentadienyl] is observed in iridium complexes. The reaction of the lithium precursor, [Li(bpzcp)(THF)], with a range of [IrCl(diene)] compounds leads to an unprecedented binding mode of the hybrid scorpionate/cyclopentadienyl ligand as η-Cp-coordinated and the formation of Ir(I) derivatives [Ir(η-Cp-bpzcp)(η-cod)] (1), [Ir(η-Cp-bpzcp){η-CH═C(Me)C(Me)═CH}] (2), [Ir(η-Cp-bpzcp)(η-coe)] (3), and [Ir(η-Cp-bpzcp)(η-CH═CH)] (4). The Ir(I) complex 4 reacts with CO or bromine to afford the compound [Ir(η-Cp-bpzcp)(CO)] (5) and the 18e Ir(III) complex [Ir(κ-N-η-Cp-bpzcpBr)Br] (6), respectively. Reaction of the iridium compounds (2-4) with CuI or [PdCl(CHCN)] yields the heterobimetallic iridium-copper or iridium-palladium complexes [Ir(η-Cp-bpzcp){η-CH═C(Me)C(Me)═CH}(μ-bpzcp){CuI(κ-NN-bpzcp)}] (7), [Ir(η-Cp-bpzcp)(η-coe)}(μ-bpzcp){CuI(κ-NN-bpzcp)}] (8), [Ir(η-Cp-bpzcp)(η-CH═CH)}(μ-bpzcp){CuI(κ-NN-bpzcp)}] (9), [Ir(η-Cp-bpzcp)(coe)}(μ-bpzcp){PdCl(κ-NN-bpzcp)}] (10), and [Ir(η-Cp-bpzcp)(η-CH═CH)(μ-bpzcp){PdCl(κ-NN-bpzcp)}] (11). All products were characterized by spectroscopic methods and the X-ray crystal structures of 1, 2, 3, 4, and 6 were also established.