Single-Step Synthesis of Dinuclear Neutral Gold(I) Complexes with Bridging Di(N-heterocyclic carbene) Ligands and Their Catalytic Performance in Cross Coupling Reactions and Alkyne Hydroamination

We report on a single-step procedure for the synthesis of dinuclear gold­(I) complexes with bridging di­(N-heterocyclic carbene) (diNHC) ligands of general formula Au 2 Br 2 L 1–9 (L = diNHC). The obtained complexes differ in the bridging group between the carbene donors and in the terminal wingtip substituents at the imidazol-2-ylidene rings. The complexes have been characterized by means of elemental analysis, NMR spectroscopy, ESI-MS spectrometry, and single-crystal X-ray structure analysis. The dinuclear gold­(I) complexes have been tested as homogeneous catalysts in technologically relevant reactions such as the cross coupling between phenyl­boronic acid and aryl bromides and the intermolecular hydroamination of alkynes. The catalytic performance has been compared for complexes Au 2 Br 2 L 1–9 and the benchmark mononuclear complex IPrAuCl.