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)(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.