A Twisted Tetragold Cyclophane from a Fused Bis-Imidazolindiylidene

The reaction between an angular bis-imidazolidinium salt and [AuCl­(SMe)₂] allowed the preparation of a discrete digold complex, with a rigid angular bridging bis-imidazolindiylidene ligand. This complex reacts with a diethynylcarbazole to afford a tetragold cyclophane that contains two bis-imidazolindiylidenes and two carbazolyl-diethynyl ligands. Both the dimetallic and the tetrametallic complexes have been characterized by spectroscopic techniques and by single-crystal X-ray diffraction. Due to the geometric constraints of the ligands, the cyclophane deviates from the expected planarity and shows a twisted structure. The work demonstrates that the rigid angular di-NHC ligand is a suitable scaffold for the reliable construction of organometallic-based metallosupramolecular assemblies.