Isolation and X-ray structure determination of the cluster dianion [Os20Hg(C)2(CO)48]2–, and the identification of the cluster previously reported with this stoicheiometry as [Os18Hg3(C)2(CO)42]2–

Abstract

The reaction of [Os₁₀C(CO)₂₄]^2–(3) with mercuric salts has been reinvestigated and with Hg(O₂CCF₃)₂ it gives mixtures of two 21 metal heteronuclear cluster dianions [Os₁₈Hg₃(C)₂(CO)₄₂]^2–(4) and [Os₂₀Hg(C)₂(CO)₄₈]^2–(5) together with an intermediate, [Os₁₀C(CO)₂₄(HgO₂CCF₃)](6) in varying proportions depending on reaction conditions; X-ray structure analysis of salts of [Os₁₀C(CO)₂₄(HgCF₃)]^–(6a), an analogue of (6), and of [Os₂₀Hg(C)₂(CO)₄₈]^2–(5) are reported, the latter having a previously unobserved metal framework consisting of two [Os₁₀C(CO)₂₄] units linked by a single mercury atom bridge; the previously reported solid state 21 metal framework, believed to be that of [Os₂₀Hg(C)₂(CO)₄₈]^2– has now been reassigned as that of the cluster dianion [Os₁₈Hg₃(C)₂(CO)₄₂]^2–(4)