THE ELECTRONIC-STRUCTURE OF (ETA-5-C5H5)2CO2 - COMMENT ON THE EXISTENCE OF A COMPLEX WITH AN UNSUPPORTED CO-CO DOUBLE-BOND

Bridging hydrido ligands possibly cause the magnetic behavior of the Cp*Co dimer formulated by Schneider et al. as CP*Co=CoCp* (Angew. Chem. Int. Ed. 1992, 30, 1124). This would agree with the calculated electron structures of the model compound CpCo=CoCp and the hydrido complexes derived from them. Also the lack of reactivity of the dimer's "naked" Co-Co double bond toward CO and ethylene can be explained without difficulty by a stabilizing influence of bridging hydrido ligands. The results of this theoretical study will certainly spark further investigations.