Coupling of co-ordinated acetylide ligands with and without CO on chalcogen-stabilised mixed-metal clusters. Synthesis and characterisation of [M(2)Fe(3)(L)(2)(CO)(6)(mu(3)-E)(2){mu-CC(Ph)C(Ph)C}] and [M(2)Fe(2)(L)(2)(CO)(4)(mu(3)-E)(2){mu-CC(Ph)(CO)C(Ph)C}] (L = eta(5)-C(5)Me(5) or eta(5)-C(5)H(5), M = Mo or W, E = S, Se or Te)

Thermolysis of a toluene solution containing [Fe(3)(CO)(9)(mu(3)-E)(2)] (E=S or Se) and [M(L)(CO)(3)(C=CPh)], M=Mo or W, resulted in coupling of co-ordinated acetylide ligands with and without CO and formation of mixed-metal clusters [M(2)Fe(3)(L)(2)(CO)(6)(mu(3)-E)(2){mu-CC(Ph)C(Ph)C}] (L=eta(5)-C(5)Me(5), M=Mo, E=S 1 or Se 2; M=W, E=S 3 or Se 4; M=W, E=Te 5; L=eta(5)-C(5)H(5), M=Mo, E=S 6 or Se 7; M=W, E=S 8 or Se 9 and [M(2)Fe(2)(L)(2)(CO)(4)(mu(3)-E)(2){mu-CC(Ph)(CO)C(Ph)C}] (L=eta(5)-C(5)H(5), M=Mo, E=S 10 or Se 11; M=W, E=S 12 or Se 13). From the thermolysis reaction of [Mo(eta(5)-C(5)H(5))(CO)(3)(C=CPh)], the new compound [{Mo(eta(5)-C(5)H(5))(CO)(2)}(2){mu-C(Ph)C(CO)C=C(Ph)}] 15 was isolated. All compounds have been characterised by IR and (1)H, (13)C and (77)Se or (125)Te NMR spectroscopy. The crystal structures of 8, 12 and 15 were elucidated by X-ray diffraction methods