Organogold oligomers: exploiting iClick and aurophilic cluster formation to prepare solution stable Au4 repeating units

Abstract

A novel synthetic method to create gold based metallo–oligomers/polymers via the combination of inorganic click (iClick) with intermolecular aurophilic interactions is demonstrated. Complexes [PEt₃Au]₄(μ-N₃C₂C₆H₅) (1) and [PPhMe₂Au]₄(μ-N₃C₂C₆H₅) (2) and {[PEt₃Au]₄[(μ-N₃C₂)₂-9,9-dihexyl-9H-fluorene]}_n (8) have been synthesized via iClick. The tetranuclear structures of 1 and 2, induced by aurophilic bonding, are confirmed in the solid state through single crystal X-ray diffraction experiments and in solution via variable temperature NMR spectroscopy. The extended 1D structure of 8 is constructed by aurophilic induced self-assembly. ¹H DOSY NMR analysis reveals that the aurophilic bonds in 1, 2, and 8 are retained in the solution phase. The degree of polymerization within complex 8 is temperature and concentration dependent, as determined by ¹H DOSY NMR. Complex 8 is a rare example of a solution stable higher ordered structure linked by aurophilic interactions.