Relative Lability and Chemoselective Transmetallation of NHC in Hybrid Phosphine‐NHC Ligands: Access to Heterometallic Complexes

The relative lability and transmetallation aptitude of trialkylphosphine and NHC donors, integrated in semi‐rigid hybrid ligands attached to [Ag 4 Br 4 ] pseudo‐cubanes, lies in favor of the NHC and is used to selectively access unprecedented NHC complexes with heterobimetallic cores, such as Ag–Cu ( 4 Cy ) and Ag–Ir ( 5 t Bu ). These can be viewed as an arrested state before the full transmetallation of both donors, which gives the homodinuclear Cu ( 3 Cy ) and Ir ( 6 Cy ) complexes. The observed NHC transmetallation aptitude and reactivity urges caution in the common notion that views the NHC as a universal spectator.