Homo- and Heteropolymetallic Complexes of the Hybrid, Ambidentate N-Heterocyclic Carbene Ligand IMes-acac

[Image: see text] The anionic 5-acetylimidazol-2-ylidene-4-olate 1(–), named as “IMes-acac”, is composed of fused diaminocarbene and acetylacetonato units in the same IMes-based imidazolyl ring. The bifunctional compound 1(–) is shown to act as an effective, ditopic bridging ligand for transition metal centers. Several new complexes supported by this ligand were prepared, including the complex [RuCl(p-Cym)(κ(2)O,O–1·H)](BF(4)) (2), which can be regarded as a metallated imidazolium salt, the homobimetallic complex [((COD)Rh)(RhCl(COD))(μ-1κ(2)O,O:2κ(1)C–1)] (4), the heterobimetallic complexes [((p-Cym)ClRu)(RhCl(COD))(μ-1κ(2)O,O:2κ(1)C–1)] (3), [((p-Cym)ClRu)(RhCl(CO)(2))(μ-1κ(2)O,O:2κ(1)C–1)] (5), [((p-Cym)ClRu)(Cu(IPr))(μ-1κ(2)O,O:2κ(1)C–1)] (9), the anionic homoleptic Cu(I) complexes [Cu(κ(1)C–1)(2)]K ([10]K) and [Cu(κ(1)C–1)(2)](NEt(4)) ([10](NEt(4))), and the heterotrimetallic complex [((p-Cym)RuCl)(2)(Cu)(μ-1κ(2)O,O:3κ(1)C–1)(μ-2κ(2)O,O:3κ(1)C–1)](PF(6)) (11). Preliminary studies on the possible preparation of supramolecular metallopolymers and electrochemical studies on the series of complexes are also reported.