HPLC STUDIES OF FE2(CO)6(LIGAND) COMPLEXES

We present a systematic study of the reverse-phase high performance liquid chromatography (HPLC) of complexes containing an Fe2(CO)6 unit bonded to a variety of organic chains, namely the butatriene moiety R2C=C=C=CR2, the butadienyl fragment, -RC=CR-RC=CR- (the ferroles), and the ring-opened cyclopentadienone diradical, -RC=CR-C(O)-RC=CR- (the flyover bridges). Since the Fe2(CO)6 unit shows an almost identical conformation in all the complexes, this enables us to evaluate the effect of the geometrical arrangement of the organic chains and of their substituents on chromatographic behaviour. Reverse-phase HPLC allows the separation of the positional isomers of ferroles and flyover bridges (R = Me or Ph), but not the cis/trans isomers of butatrienes (R = H or Me).