Synthesis and spectroscopic characterization of heterobimetallic (α-alkynyl)iron-cobalt hexacarbonyl complexes, μ-(1-σ, 2-3, η2-R2C-CCR′)][(CO)3Fe-Co(CO)3] and [μ-(1-σ, 2-3, η2-H2C-CCCH2OH)] [(CO)3Fe-Co(CO)2(PPh3)]

The title compounds have been prepared from reactions of Co₂(CO)₆(μ-HOR₂CC₂R′) or Co₂(CO)₆(μ-HOR₂CC₂CR₂OH) complexes with Fe(CO)₅ in acetone. In the latter set of reactions the homobimetallic butatriene compounds, Fe₂(CO)₆-(μ-R₂CCCCR₂), are also obtained. The striking feature of these reactions is the ability of Fe(CO)₅ to dehydroxylate the organic moiety and to replace a Co(CO)₃ unit forming mixed iron-cobalt derivatives. A direct interaction between the iron and the carbon atom, originally bearing the lost -OH group, is evident from the bulk of the spectroscopic data; thus the organic chain acts as an overall 5 electron donor, according to the E.A.N. formalism. The heterobimetallic compounds have been characterized by elemental analysis, mass spectrometry, IR spectroscopy and NMR studies. For the phosphine derivative FeCo(CO)₅(PPh₃)(H₂CC₂OH) a crudely refined X-ray analysis has been performed.