[IrCl{N(CHCHPtBu2)2}]-: a versatile source of the Ir(I)(PNP) pincer platform

Dalton Trans. 2014 Mar 21;43(11):4506-13. doi: 10.1039/c3dt53304b.

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.