Synthesis and Characterization of 1,12-Bis(ferrocenyl)-1,3,5,7,9,11-dodecahexayne and Its Coordination to Triosmium and Dicobalt Carbonyls

1,12-Bis(ferrocenyl)-1,3,5,7,9,11-dodecahexayne ( 1 ) was synthesized by in situ oxidative coupling of the terminal triyne FcC⋮CC⋮CC⋮CH ( 5 ). The reaction of hexayne 1 with Os 3 (CO) 11 (NCMe) ( 2 ) yielded the new hexaosmium compound Os 6 (CO) 22 (μ 6 -η 8 -FcC 4 C⋮CC⋮CC 4 Fc) ( 6 ) in 15% yield. Compound 6 contains two open triosmium clusters coordinated parallel to opposite sides of the hexayne chain. Compound 1 also reacted with Co 2 (CO) 8 to afford Co 8 (CO) 24 (μ 8 -η 2:η 2:η 2:η 2 -FcC 2 C⋮CC 4 C⋮CC 2 Fc) ( 7 ) in 35% yield. In compound 7, four dicobalt hexacarbonyl groups have been added to the hexayne chain. Compounds 1, 6, and 7 were characterized by IR, 1 H NMR, and single-crystal X-ray diffraction analyses. Differential pulse voltammograms show only one two-electron oxidation peak for compounds 1, 6, and 7, indicating that there is no detectable electronic communication between the two terminal ferrocenyl groups by this method.