Dynamic behaviour of high-nuclearity osmium–mercury clusters in solution

Abstract

The dynamic behaviour of the Hg-capped decaosmium cluster anions [Os₁₀C(CO)₂₄(HgY)]^–[Y = Cl, Br, I, CF₃ or Mo(CO)₃(cp); cp =η⁵-C₅H₅]2a–2e as well as the Hg-linked cluster [{Os₁₀C(CO)₂₄}₂Hg]^2–3 in solution has been investigated by variable-temperature ¹³C NMR spectroscopy. The mercury fragment HgY has been found to be highly mobile on the surface of the Os₁₀ cluster core and to undergo rapid exchange between the different µ-bridging and µ₃-capping sites of the parent cluster. Based on the spectroscopic results a unified model for the observed metal-core fluxionality is proposed.