Dicobalt Complexes with syn ‐ and anti ‐Coordinated μ‐Cycloheptatriene Bridges

Despite their similar composition the two cycloheptatriene‐bridged dinuclear complexes [(CpCo) 2 (μ‐C 7 H 8 )] and [(Cp * Co) 2 (μ‐C 7 H 8 ] 1 , which are accessible in good yields by reaction of [CpCo(η 4 ‐C 7 H 8 )] and [Cp * Co (η 4 ‐C 7 H 8 )] with [CpCo(C 2 H 4 ) 2 ] and [Cp * Co‐(C 2 H 4 ) 2 ] respectively, have very different structures. The Cp complex shows an unsymmetrical syn ‐bonding (σ 2 , η 2 :η 3 ) of the cycloheptatriene to a (CpCo) 2 skeleton, whereas in 1 a structure with anti ‐cycloheptatriene bridge (η 4 :η * ) is realized for the first time.