Fast and Reversible Intramolecular Cleavage of an Au−C Bond in the Spiked-Triangular Metal Complexes [Fe₃Au(μ₄,η²-C⋮C^tBu)(CO)₉(PR₃)] (R = Ph, ⁱPr)

The C−S bond cleavage in the alkynethiolate ligand of the compound Li[Fe₃(μ₃-SC⋮C^tBu)(CO)₉] (1a) takes place in its reaction with [AuClPR₃] (R = Ph, ⁱPr), affording the complexes [Fe₃Au(μ₄,η²-C⋮C^tBu)(CO)₉(PR₃)] (R = Ph (3a), ⁱPr (3b)). The gold fragment displays an unexpected bonding mode, and a fast and reversible process of oxidative addition/reductive elimination of the Au−C bond has been observed in solution.