Electrochemical and Spectroscopic Studies on the Reduction of Linear Mo/Fe/S Complexes

The reduction studies of linear Mo/Fe/S complexes, [CI2FeS2MoS2FeCl2]2 Complex 1, and [CI2FeS2MoS2]2, Complex 2 which are models of enzyme nitrogenase, were studied. The reduction products were stabilized by the presence of chloride. However, the reduced complex dimerized, to form dimer of trianion. UV-Visible/ IR/ Raman spectroscopic methods were employed to study the reduction products of these complexes. Electrochemical methods were also used to understand the redox properties of the complex. Reduction of Complex 1 was studied by coulometric reduction using the mediator benzil and by chemical reduction, using TBABH4 as the reducing agent. Both reduction methods showed similar bands in IR spectrum, indicating that the reduction products were the same by both methods. Moreover, the bands at 457 and 466 cm-1 which were repeatedly seen after reduction in IR, is presumed to be the bands pertaining to , the dimer of the trianion. Mossbauer spectrum and the elemental analysis gave evidence to the dimeric structure that we proposed. However elemental analysis done after reducing Complex 2 by TBABH4 , were not very conclusive. So more work needs to be done to confirm the products formed by the reduction of this complex