[IrCl{N(CHCHPtBu2)2}]−: a versatile source of the IrI(PNP) pincer platform

Abstract

The iridium(II) complex [IrCl{N(CHCHPtBu₂)₂}] is reduced by KC₈ to give the anionic iridium(I) pincer complex [IrCl{N(CHCHPtBu₂)₂}]⁻ which was isolated and fully characterized upon stabilization of the counter cation with crown ether as [K(15-cr-5)₂][IrCl{N(CHCHPtBu₂)₂}]. This unprecedented anionic iridium(I) pincer complex completes the unusual, structurally characterized Ir^I/Ir^II/Ir^III redox series [IrCl{N(CHCHPtBu₂)₂}]^−/0/+, all in a square-planar coordination geometry, emphasizing the versatility of this PNP pincer ligand in stabilizing a broad range of oxidation states. The anionic chloro complex is a versatile source of the Ir(PNP) platform. Its reactivity was examined towards chloride ligand substitution against CO and N₂, and oxidative addition of C-electrophiles, C–H bonds and dioxygen, allowing for the isolation of iridium(I) and iridium(III) (PNP) carbonyl, hydrocarbyl and peroxo complexes which were spectroscopically and crystallographically characterized.