Abstract
Neutral 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)(2)M-2} (M=Ag, Au) [L=2,2-dioxo-biphenyl, NHC=1-methyl-3-(-2-phenyl-acetamido)-imidazol-2-ylidene (1f); L=2,2'-dioxo-binapthyl, NHC=1-methyl-3-(-2-phenyl-acetamido)-imidazol-2-ylidene (2e)] 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)}Ag-2 complexes. Quite interestingly, a weaker argentophilic interaction was observed in the solid state X-ray crystalllographic structure of binapthyl derivative 2e, as Ag center dot center dot center dot Ag contact of 3.3011 angstrom while in case of biphenyl derivative 1f there is no such aurophilic interaction exhibited a significant Au center dot center dot center dot Au contact.