Reactions of Gold(I) Acetylides with 1,1′-Diisocyanoferrocene: From Orthodox to Unorthodox Behavior

Abstract

1,1′-Diisocyanoferrocene (1) reacts with the gold(I) acetylides [Au(C≡C-p-C6H4R)]n (2a R = CF3, 2b R = H, 2c R = OMe, 2d R = NMe2) to afford the respective dinuclear gold complexes [{Au(C≡C-p-C6H4R)}2(μ-1)] (3), whose aurophilic aggregation in the solid state depends on the nature of the substituent R. The product of the reaction of 1 with [Au(C≡C-Fc)]n (2e, Fc = ferrocenyl) is the hexanuclear gold cluster [(Fc-C≡C-Au-C≡N-C5H4)Fe{C5H4-N═C(Au)-C≡C-Fc}]3, which is composed of three subunits 4 and exhibits an unusual arrangement of gold atoms. The formation of (4)3 is based on a different specific reaction of the two chemically equivalent functional groups of 1 with 2e, viz., coordination and 1,1-insertion. This “schizoid” behavior apparently is a novel variant of induced reaction asymmetry and constitutes a new phenomenon in chemistry. The reaction of 2e with 1,1′-bis(diphenylphosphanyl)ferrocene (5) affords the expected [(Au-C≡C-Fc)2(μ-5)] (6), which does not exhibit aurophilic interactions.