Neutral Binuclear Ag(I) and Au(I) N‐Heterocyclic Carbene Complexes of Axially Chiral and Racemic Scaffolds: Synthesis and Characterization

Abstract

AbstractNeutral bimetallic silver(I) and gold(I) complexes of N‐ heterocyclic carbene ligands derived from racemic biphenyl and axially chiral binapthyl frameworks have been synthesized and structurally characterized. In particular, the neutral bimetallic silver(I) complexes of the type {L(NHC)2M2} (M=Ag, Au) [L=2,2′‐dioxo‐biphenyl, NHC=1‐methyl‐3‐(‐2‐phenyl‐acetamido)‐imidazol‐2‐ylidene (1 f); L=2,2′‐dioxo‐binapthyl, NHC=1‐methyl‐3‐(‐2‐phenyl‐acetamido)‐imidazol‐2‐ylidene (2 e)] are synthesized from the corresponding imidazolium chloride salts (1‐2)d by the reaction with Ag2O in quantitative yields. The gold(I) complexes are synthesized by the transmetallation of their corresponding {L(NHC)2}Ag2 complexes. Quite interestingly, a weaker argentophilic interaction was observed in the solid state X‐ray crystalllographic structure of binapthyl derivative 2 e, as Ag⋅⋅⋅Ag contact of 3.3011 Å while in case of biphenyl derivative 1 f there is no such aurophilic interaction exhibited a significant Au⋅⋅⋅Au contact.