Reactivity of metal acetylides with chalcogen-bridged metal carbonyl cluster in presence of free alkyne molecule:: synthesis and characterisation of [(η5-C5Me5)MFe3(μ3-S){(μ3-C(H)=C(R)S}(CO)6(μ3-CCPh)] (R = Ph, n-Bu and M = W, Mo) and [(η5-C5Me5)MFe3(μ3-S){(μ3-C(Fc)=C(H)S}(CO)7(μ3-CCPh)] (M = W, MO)

Photolysis of benzene solution of [Fe-3(CO)(9)(mu(3)-S)(2)](1),[(eta(5)-C5Me5)M(CO)(3)(CdropCPh)] (2a: M = W, 2b: M = Mo) and HC drop CR (3a: R = Ph, 3b: R = n-Bu, 3c: R = {(eta(5)-C5H5)(eta(5)-C5H4)Fe}(Fc) yields two types of clusters: [(eta(5)-C5Me5)MFe3(mu(3)-S){(mu(3)-C(H) = C(R)S}(CO)(6)(mu(3)-CCPh)] (4: M=W, R=Ph; 5: M=Mo, R=Ph: 6: M=W, R=n -Bu; 7: M=Mo, R=n-Bu) and [(eta(5)-C5Me5)MFe3(mu(3)-S){(mu(3)-C(Fc)=C(H)S}(CO)(7)(mu(3)-CCPh)] (8: M=W; 9: M=Mo) featuring new C-S bond formation. The formation of 8 and 9 involve an unusual head to tail flip of the coordinated acetylide group. All compounds have been characterised by IR and H-1- and C-13-NMR spectroscopy. The structures of 5 and 8 have been established by X-ray crystallography. (C) 2003 Elsevier Science B.V. All rights reserved.