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

Abstract

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 Os3(CO)11(NCMe) (2) yielded the new hexaosmium compound Os6(CO)22(μ6-η8-FcC4C⋮CC⋮CC4Fc) (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 Co2(CO)8 to afford Co8(CO)24(μ8-η2:η2:η2:η2-FcC2C⋮CC4C⋮CC2Fc) (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, 1H 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.