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