Assembly, disassembly, and reassembly of a large mercury cobalt carbonyl cluster, Hg9Co6(CO)18

Article abstract of DOI:10.1021/om00097a004

The reaction of an aqueous basic solution of Hg(CN)₂ with Hg[Co(CO)₄]₂ in methanol/water formed the largest mercury-containing cluster yet reported, Hg₉Co₆(CO)₁₈ (1). A single-crystal X-ray structure determination on the bis(acetone) solvate, Hg₉Co₆(CO)₁₈·2(CH₃) ₂CO [P2₁/c; a = 14.339 (5) A?, b = 21.024 (6) A?, c = 18.535 (8) A?, β = 94.48 (3)°; V = 5570 (36) A?³; Z = 4; R₁ = 8.1%, R₂ = 12.0%], showed 1 to have fac-(CO)₃Co fragments at the corners of a rectangular trigonal prism with a mercury atom at the center of each edge. In addition to forming a 1:3 adduct with Et₄N⁺I^-, cluster 1 reacted with HgX₂ compounds forming monocobalt compounds (CO)₃Co(HgX)₃ (X = I (2), Cl (3), CF₃CO₂). The chloro derivative 3 re-formed 1 in high yield when treated with Ph₃P. Possible mechanisms are discussed. Compound 2 was used to form analogous derivatives, (CO)₃Co(HgY)₃: Y = p-CH₃C₆H₄SO₃ with silver toluenesulfonate and Y = Ph with phenyllithium. It also formed an 1:1 adduct with n-Bu₄NI.