Synthesis and spectroscopic characterization of heterobimetallic (α-alkynyl)iron-cobalt hexacarbonyl complexes, μ-(1-σ, 2-3, η 2-R 2C-CCR′)][(CO) 3Fe-Co(CO) 3] and [μ-(1-σ, 2-3, η 2-H 2C-CCCH 2OH)] [(CO) 3Fe-Co(CO) 2(PPh 3)

Abstract

The title compounds have been prepared from reactions of Co 2(CO) 6(μ-HOR 2CC 2R′) or Co 2(CO) 6(μ-HOR 2CC 2CR 2OH) complexes with Fe(CO) 5 in acetone. In the latter set of reactions the homobimetallic butatriene compounds, Fe 2(CO) 6-(μ-R 2CCCCR 2), 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(PPh 3)(H 2CC 2OH) a crudely refined X-ray analysis has been performed.