Synthesis and structural characterization of organometallic cyclynes: novel nanoscale, carbon-rich topologies

A combination of Pd- and Cu-catalyzed couplings make the ferrocene and cyclobutadiene(cyclopentadienylcobalt)-based half-wheels and the cyclobutadiene(cyclopentadienylcobalt)-based seco-wheel accessible. These targets can formally be constructed by fusing two or three organometallic benzohexadehydro[14]annulenes along an alkyne unit. In addition, a ferrocene-based, enlarged version of the half wheel was prepared. This target compound is obtained by formally fusing two organometallic benzododecadehydro[18]annulenes. Single crystal structures of three target molecules, the cyclobutadiene complex C51H37Co, the ferrocene derivative C51H36Fe, and the cyclobutadiene complex C69H59Co were performed to verify the proposed geometries.