Facile generation of iridium PCcarbeneP pincer complexes via water elimination from an alcohol proligand

Abstract

We report the facile generation of Ir PC_carbeneP pincer systems. These systems are accessed from the reaction between [IrCl(COD)]₂ and a bis(diphenyl)phenylene P(OH)P proligand (1) with concomitant dehydration, followed by salt metathesis/ligand exchange in the case of cationic examples. In contrast to previously reported double C–H activation synthetic strategies to access similar complexes, accessing Ir PC_carbeneP complexes through dehydration proceeds rapidly at room temperature and provides the first example of the incorporation of phosphino aryl substituents. The generated complexes are shown to possess the ability to activate inert C–H bonds and partake in ligand cooperativity. Mechanistic evidence suggests that divergent C–H and O–H activation pathways of ligand 1 ultimately lead to the same Ir PC_carbeneP product (2). It is hoped that the stability and synthetic accessibility of these complexes will encourage their increased use in catalyst surveys.