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

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)­(κ2O,O–1·H)]­(BF4) (2), which can be regarded as a metallated imidazolium salt, the homobimetallic complex [((COD)­Rh)­(RhCl­(COD))­(μ-1κ2O,O:2κ1C–1)] (4), the heterobimetallic complexes [((p-Cym)­ClRu)­(RhCl­(COD))­(μ-1κ2O,O:2κ1C–1)] (3), [((p-Cym)­ClRu)­(RhCl­(CO)2)­(μ-1κ2O,O:2κ1C–1)] (5), [((p-Cym)­ClRu)­(Cu­(IPr))­(μ-1κ2O,O:2κ1C–1)] (9), the anionic homoleptic Cu­(I) complexes [Cu­(κ1C–1)2]K ([10]­K) and [Cu­(κ1C–1)2]­(NEt4) ([10]­(NEt4)), and the heterotrimetallic complex [((p-Cym)­RuCl)2(Cu)­(μ-1κ2O,O:3κ1C–1)­(μ-2κ2O,O:3κ1C–1)]­(PF6) (11). Preliminary studies on the possible preparation of supramolecular metallopolymers and electrochemical studies on the series of complexes are also reported.