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

Abstract

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)]2 compounds leads to an unprecedented binding mode of the hybrid scorpionate/cyclopentadienyl ligand as η5-Cp-coordinated and the formation of Ir­(I) derivatives [Ir­(η5-Cp-bpzcp)­(η4-cod)] (1), [Ir­(η5-Cp-bpzcp)­{η4-CH2C­(Me)­C­(Me)CH2}] (2), [Ir­(η5-Cp-bpzcp)­(η2-coe)2] (3), and [Ir­(η5-Cp-bpzcp)­(η2-CH2CH2)2] (4). The Ir­(I) complex 4 reacts with CO or bromine to afford the compound [Ir­(η5-Cp-bpzcp)­(CO)2] (5) and the 18e– Ir­(III) complex [Ir­(κ-N-η5-Cp-bpzcpBr2)­Br2] (6), respectively. Reaction of the iridium compounds (2–4) with CuI or [PdCl2(CH3CN)2] yields the heterobimetallic iridium–copper or iridium–palladium complexes [Ir­(η5-Cp-bpzcp)­{η4-CH2C­(Me)­C­(Me)CH2}­(μ-bpzcp)­{CuI­(κ2-NN-bpzcp)}] (7), [Ir­(η5-Cp-bpzcp)­(η2-coe)2}­(μ-bpzcp)­{CuI­(κ2-NN-bpzcp)}] (8), [Ir­(η5-Cp-bpzcp)­(η2-CH2CH2)2}­(μ-bpzcp)­{CuI­(κ2-NN-bpzcp)}] (9), [Ir­(η5-Cp-bpzcp)­(coe)2}­(μ-bpzcp)­{PdCl2(κ2-NN-bpzcp)}] (10), and [Ir­(η5-Cp-bpzcp)­(η2-CH2CH2)2(μ-bpzcp)­{PdCl2(κ2-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.

Iron(ii) complexes supported by pyrazolyl-substituted cyclopentadienyl ligands: synthesis and reactivity

“…1 Hybrid ligands containing two pyrazolyl groups and a cyclopentadienyl unit represent a particularly interesting class of heteroscorpionate ligands. [2][3][4][5][6][7] Bis( pyrazolyl)cyclopentadienyl complexes of group 3 2 and group 4 3 transition metals as well as tungsten, 4 iridium, 5 zinc, 6 and lanthanum 7 have been reported. These compounds have garnered interest for their capacity as olefin 2a and ringopening 2b,6a,b polymerization catalysts and as mediators of carbon dioxide fixation 2d and hydroamination 7 reactions.…”