Heterobimetallic Au I /M (M = Ru II , Ir III ) Complexes Supported by a Dipyridylamine Functionalized Triazol-5-ylidene

In recent years, the design and construction of heterobimetallic complexes have gained a great deal of attention owing to their various applications in fields such as medicinal chemistry and materials, and more recently in their emerging synthetic applications in catalysis. In this work, we report the preparation of a dipyridylamine-functionalized 1,2,3-triazolium salt ( 1 ), which can be readily deprotonated in the presence of AuCl(SMe 2 ), generating the monometallic triazol-5-ylidene gold complex 2 . Taking advantage of the free dipyridylamine fragment available in 2, the addition of [Ru( p -cymene)Cl 2 ] 2 and [Ir(Cp*)Cl 2 ] 2 precursors permits the formation of the air-stable heterobimetallic Au I /Ru II ( 3 ) and Au I /Ir III ( 4 ) complexes in good yields. Alternative synthesis of the heterobimetallic complexes by the initial coordination of the Ru ( 5 ) and Ir ( 6 ) centers to the dipyridyl ligand and subsequent metalation at the triazolylidene scaffold was also achieved. All complexes have been fully characterized by multinuclear NMR spectroscopy, elemental analysis, and, in the case of complexes 2 and 3, single-crystal X-ray diffraction. Furthermore, the photophysical properties of the heterobimetallic complexes 3 and 4 and their preliminary catalytic applications in the tandem hydration-transfer hydrogenation of haloalkynes are discussed.