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