Synthesis and spectroscopic characterization of (CO)(6)Fe-2{mu-EC(H)=C(H)E'} (E not equal E'; E,E'=S, Se, Te) and (CO)(6)Fe-2{mu-TeC(H)=C(H)Te}. Structural characterization of (CO)(6)Fe-2{mu-SC(Ph)=C(H)Se} and (CO)(6)Fe-2{mu-SC(H)=C(Ph)Te}

When acetylene gas was bubbled through methanol solutions containing the mixed-chalcogenide compounds (CO)(6)Fe-2(mu-EE') (E not equal E'; E, E' = S, Se, Te), the acetylene adducts (Co)(6)Fe-2{mu-EC(H)=C(H)E'} (1, 52%, E, E' = S, Se; 2, 46%, Et E' = S, Te; 3, 38%, E, E' = Se, Te) were obtained, In addition, trace amounts of the homochalcogenide derivatives (CO)(6)Fe-2-{mu-EC(H)=C(H)E} (E = S, Se, Te) were also obtained. The Te-2 compound (CO)(6)Fe-2{mu-TeC-(H)=C(H)Te) (4) was obtained in 32% yield from the reaction of (CO)(6)Fe-2(mu-Te-2) with acetylene. Compounds 1-4 were characterized by IR and H-1, C-13, Se-77, and Te-125 NMR spectroscopy. Crystallographic analysis of the phenylacetylene adducts (CO)(6)Fe-2{mu-SC(Ph)=C(H)Se} (5) and (CO)(6)Fe-2(CO)(6)Fe-2{mu-SC(H)=C(Ph)Te) (6) were carried out. The structures of both 5 and 6 can be described as Fe(2)SE (E = Se, Te) tetrahedral butterfly cores containing the phenylacetylene as a bridge between the two wingtip chalcogen atoms, with three terminally bonded carbonyl groups on each Fe atom.