Tail-to-tail carbon-carbon bond coupling of acetylides on chalcogen-bridged Fe/W mixed-metal clusters

Abstract

On thermolysis of a toluene solution containing [Fe₃(CO)₉(μ₃-E)₂] (E = S 1a, Se 16 or Te 1c) and [W(η⁵-C₅Me₅)₂(CO)₃(C≡CPh)]₂ the new clusters [W₂Fe₃(η⁵-C₅Me₅)₂(CO)₆(μ³-E)₂{μ⁴-CC(Ph)C(Ph)C}] (E = S 3, Se 4 or Te 5) were isolated. Compounds 3-5 were characterised by IR and ¹H, ¹³C, ⁷⁷Se and ¹²⁵Te NMR spectroscopy. The crystal structure of 3 was elucidated by X-ray diffraction methods. It shows a novel tail-to-tail coupling of substituted acetylides on a sulfur-bridged mixed-metal Fe-W cluster.