A 197Au Mossbauer study of reaction products of trimeric 1-benzyl-2gold(I)-imidazole leading to Au(I) carbene or Au(I) imidazoline complex and trinuclear Au(III) imidazolylderivatives. X-ray crystal structure of [(m-1-benzylimidazolatto-N3C2)Au)3I2]

Reactions of the trinuclear [Au3Rim3] compound (Rim = [μ-1-benzylimidazolato-N3,C2] with several reagents capable of oxidative addition have been investigated by 197Au Mössbauer spectroscopy. The reaction products are either AuI carbene mononuclear and binuclear complexes or trinuclear AuIII and mixed-valence compounds. The X-ray crystal structure of the mixed-valence complex [AuIIIAuI2Rim3I2] has been determined. Two two-coordinate AuI centres show average AuC and AuN distances of 2.02(3) and 2.04(2) Å and average CAuN angles of 175.0(1.2)°, whereas the four-coordinate AuIII centre gives AuC and AuN 1.96(4) and 1.91(3) Å with the CAuN angle 170.5(1.6)°, and AuI average distances 2.598(3) Å, with an IAuI angle 175.8(1)°. The AuAu intramolecular distances [Au(1) ⋯ Au(2) 3.432(3), Au(1) ⋯ Au(3) 3.508(3), Au(2) ⋯ Au(3) 3.464(3) Å] indicate a weak metal-metal interaction.