Dynamic Au-C σ-Bonds Leading to an Efficient Synthesis of []Cycloparaphenylenes ( = 9-15) by Self-Assembly.

The transmetalation of the digold(I) complex [AuCl(dcpm)] () (dcpm = bis(dicyclohexylphosphino)methane) with oligophenylene diboronic acids gave the triangular macrocyclic complexes [Au(CH) (dcpm)] ( = 3, 4, 5) with yields of over 70%. On the other hand, when the other digold(I) complex [AuCl(dppm)] () (dppm = bis(diphenylphosphino)methane) was used, only a negligible amount of the triangular complex was obtained. The control experiments revealed that the dcpm ligand accelerated an intermolecular Au(I)-C σ-bond-exchange reaction and that this high reversibility is the origin of the selective formation of the triangular complexes.