New Fe/Mo/S Clusters with MoFe3S3 Cuboidal Cores Similar to the One in the Fe/Mo Cofactor of Nitrogenase. Synthesis and Structural Characterization of the (C14-cat)MoFe3S3(PEt3)2(CO)6 and (C14-cat)Mo(O)Fe3S3(PEt3)3(CO)5 Clusters

The reaction of the double cubane [(Cl4-cat)MoFe3S4(PEt3)3]2 with CO in THF solution affords the neutral, heterometallic clusters (Cl4-cat)MoFe3S3(PEt3)2(CO)6, at 350 psi, and (Cl4-cat)Mo(O)Fe3S3(PEt3)3(CO)5, under ambient pressure. The corner-sulfide voided MoFe3S3 cuboidal cores of these clusters make them potentially useful synthetic precursors for a structural model of the Fe/Mo cofactor.