Formation and Reactivity of a Co4‑μ-Alkyne Cluster from a Co(I)-Alkene Complex

Highly reactive Co­(I) complex [CpCo­(H2CCHSiMe3)2] (1) easily forms a tetranuclear Co4 cluster in hydrocarbon solvents under mild conditions, possessing a bridging alkyne ligand stemming from an unusual C–H activation of the H2CCHSiMe3 ligand. The cluster was structurally characterized, and the catalytic reactivity in [2+2+2] cycloaddition, hydroformylation, and hydrogenation reactions investigated. Interesting differences were found and compared to the mononuclear complex 1, which could be relevant for the real catalytically active species.