Synthesis of the clusters with the molybdenum iron sulfide core and core rearrangements of molybdenum/iron/sulfur clusters under reducing conditions.

Intrigued by unique functions and structures of the FeMo-cofactor (FeMoco) and the P-cluster in the nitrogenase, the synthesis of the new Mo/Fe/S clusters have been achieved. The reaction of the edge-fused (Cl4-cat) 2Mo2Fe6S8(PR3)6 (R = Et, nPr) (I) double cubanes with a high pressure of CO produced the (Cl4-cat)Mo(L)Fe3S3(PR 3)n(CO)m (L = O, Pyridine, or PnPr 3, n = 2 or 3, m = 4, 5 or 6, R = Et or nPr) clusters (II) which have a partial structural motif of the FeMoco and show a dramatic structural change upon addition-removal of two electrons. In the presence of DMF, the same reaction produced an additional product, Fe(DMF)Cl(Cl4-cat)2Mo2Fe2S 4(PEt3)2ClFe4S4(PEt 3)3(CO)6Cl (III), as well as II, Mo2Fe2S4(PEt3) 4 (IV) and Fe4S4Cl(PEt3) 3(CO)6 (V). The isolation of III, IV and V from the reaction of I and CO inspired the new synthetic approach for high nuclearity Mo/Fe/S clusters. An alternative synthetic route for I has been developed and generalized by the synthesis of the [(Cl4-cat)2Mo2Fe2S 3O(PEt3)3Cl]- (VI) and the known Fe6S6(PEt3)4Cl 2 (VII) clusters.PhDInorganic chemistryPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125434/2/3016861.pd