Self‐Assembly of a Bis‐NHC Ligand and Coinage Metal Ions: Unprecedented Metal‐Driven Chemistry between the Tri‐ and Tetranuclear Species.

The discrete multinuclear AgI−NHC complexes [Agn(1)n)](X)n; (n=3 or 4, X=BF4, PF6), synthesized from a bis‐NHC ligand 1 and AgI ions via multiligand self‐assembly, were observed to be in equilibrium between two forms (tri‐ and tetranuclear) in solution on the NMR timescale, which is unprecedented in CNHC‐donor based chemistry. The existence of both the species was confirmed by various studies such as NMR (1H, VT, 2D‐DOSY) and ESI‐MS analysis along with concentration studies. Importantly, replacing AgI with other coinage metals (AuI and CuI) was found to alter the phenomenon entirely: a slow exchange from the tetra‐ to trinuclear species was noticed for the AuI complexes (4 a, b), whereas no such process was detected in case of the CuI complexes (5 a, b). [ABSTRACT FROM AUTHOR]