Syntheses and Characterization of Cubane-Type Clusters with Molybdenum-Iron-Sulfur (Mo3FeS4) or Molybdenum-Nickel-Sulfur (Mo3NiS4) Cores. X-Ray Structures of (CH3C6H4SO3)4*7H2O and Cl4, and Discrete Variational (DV)-Xα Calculation of the Electronic...

Article abstract of DOI:10.1246/bcsj.68.2769

Reaction of the incomplete cubane-type cluster ⁴⁺ (A) with iron gives a novel cubane-type aqua cluster (CH3C6H4SO3)4*7H2O (B').An ammonia coordinated derivative cluster Cl4 (C') is also synthesized.X-ray structural analyses of B' and C' revealed that the clusters, ⁴⁺ (B) and ⁴⁺ (C), have an approximate symmetry of C_3v.The iron atom has fairly regular tetrahedral geometry in both clusters.The effective magnetic moments of B' at 2.16 K and 269.95 K are 2.78 and 3.26 B.M., respectively. 57Fe-Moessbauer spectroscopy showed that the oxidation states of iron in B' and C' were assignable to be +2.39 and +2.54, respectively, which indicates that the reaction is a reductive addition of an iron atom to the Mo3S4 core in A.The cyclic voltammograms of A, B, and ⁴⁺ (D) show three consecutive one electron reductive steps, respectively, and the oxidation states of metals in B and D are assigned as Mo^IVMo^III2M^II (M = Fe, Ni).Discrete variational (DV)-Xα calculation of B, C, and D explains the magnetic behavior, XPS spectra, and reactivity toward CO, C2H2, and C2H4.