Addition of propargyl groups to [Fe2(CO)6(μ-E2] (E = S, Se, Te) and reactions of [Fe2(CO)6(μECH2CCH)2] (E = S, Se) with Co2(CO)8 ;: Crystal structures of [Fe2(CO)6(μ-SeCH2CCH)2], [Fe2(CO)6{(μ-SCH2C=CH)Co2(CO)6}2] and [Fe2(CO)6{(μ-SeCH2C=CH)Co2(CO)6}2]

The dianionic compounds [Fe-2(CO)(6)E-2](2-) (E = S, Se, or Te) show contrasting reactivitites toward propargyl bromide. When E = S or Se, [Fe-2(CO)(6) (mu-ECH2C=CH)(2)] are isolated from the reactions of [Fe-2(CO)(6)E-2](2-) with propargyl bromide. The S-compound, [Fe-2(CO)(6)(mu-SCH2C=CH)(2)] is isolated in only one isomeric form (a, e) in which the two (CH2C=CH) moieties have different orientations, whereas the Se-compound is isolated in two isomeric forms, (a, e) and (e, e). Reaction of [Fe-2(CO)(6)Te-2](2-) with propargyl bromide yields [Fe-2(CO)(6)(mu-TeCH=C=CH2)(mu-TeCH2C=CH)], which also exists in two isomeric forms. Room temperature reactions of [Fe-2(CO)(6)(mu-ECH2C= CH)(2)] with two equivalents of Co-2(CO)(8) yielded [Fe-2(CO)(6){mu-ECH2C= CH)Co-2(CO)(6)}(2)] (E = S, a, e isomer; E = Se, a, e and e, e isomers. All new compounds were characterised by IR and H-1, C-13, Se-77, and Te-125 NMR spectroscopy. Structures of [Fe-2(CO)(6)(mu-SeCH2C=CH)(2)] (e, e), [Fe-2(CO)(6) {(mu-SCH2C = CH)Co-2(CO)(6)}(2)] (a, e), and [Fe-2(CO)(6) {(mu-SeCH2C=CH)Co-2 (CO)(6)}(2)] (e, e) were further established by single crystal X-ray diffraction methods.