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

摘要

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.