The Co3(CO)9C moiety acts as an electroreducible marker for estradiol detection enhancement in the HPLC-ED technique

The tricobalt enneacarbonylethynylestradiol derivative Co3(CO)9CCCE (E=estradiol) proved to be elusive, due to the strong electron-withdrawing properties of both the 17β OH and the Co3(CO)9C groups. However, the advantage of introducing the Co3C core, which undergoes a reversible 1 e reduction, can be achieved by the interposition of a spacer arm, namely C(O)NHC6H4, generated in situ during the synthesis in the appropriate experimental conditions. The corresponding bioorganometallic product Co3(CO)9CC(O)NHC6H4CCE retains an acceptable relative binding affinity for estradiol receptor affording a new electrochemical marker suitable for biochemical analyses.