title: {AsW9O33}-{Mo3S4} based polyoxometalates including a metal-metal bond with Pd or Ni. Synthesis, structure and studies in solution.
abstract: Heterometallic cuboidal clusters [Mo(3)S(4)M(H(2)O)(9)Cl](3+) M = Pd or Ni react with the trivacant [AsW(9)O(33)](9-) anion to give tetramodular complexes [(H(2)AsW(9)O(33))(4){Mo(3)S(4)M(H(2)O)(5)}(2)](20-) (M = Pd for anion 2 and M = Ni for anion 3) in good yield. Both anions crystallized as single crystals of potassium salts to give K-2 and K-3 salts which have been characterized structurally by X-ray diffraction. Both compounds are isomorphous and the anions 2 and 3 are described as two dimeric moeties, associated by internal hydrogen bonds, electrostatic interactions involving four outer potassium ion and coordination bonds within a central {M(2)S(2)} unit containing a M-M metallic bond. Studies in solution reveal that the dimeric association is maintained in solution in the 2 × 10(-4)-2 × 10(-3) mol L(-1) range. Conversely, in the presence of exogeneous ligands, such as iodide or pyridine the UV-vis data are consistent with the dissociation of the anion 2 into monomer through a Pd-L coordination bond (L = I(-) or Py). Furthermore, (183)W NMR spectrum of 2 shows that molecular structure of 2 is retained in solution. Elemental analysis and IR are also supplied. Electrochemical behavior of 2 and 3 are given and compared with the Pd or Ni free parent anion. The CVs are dominated mainly by irreversible reduction or oxidation processes, where the peak potentials appear dependent upon the ionic charge of the complex. However, the CV of the Pd-containing anion (2) is consistent with the deposition of Pd metal at the electrode, which gives rise to an oxidation process into palladium oxide.
authors.affiliation: University of Versailles Saint Quentin, Institute Lavoisier of Versailles, ILV, UMR CNRS 8180, Versailles, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Duval
authors.forename: Jérôme
authors.initials: J
authors.lastname: Marrot
authors.forename: Corine
authors.initials: C
authors.lastname: Simonnet-Jégat
authors.forename: Israël Martyr
authors.initials: IM
authors.lastname: Mbomekallé
authors.forename: Maxim
authors.initials: M
authors.lastname: Sokolov
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Cadot
mesh_terms: D015394:Molecular Structure; D008982:Molybdenum; D009532:Nickel / Q000737:chemistry*; D010087:Oxides; D010165:Palladium / Q000737:chemistry*; D012996:Solutions; D013440:Sulfides; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D008982:Molybdenum; D009532:Nickel; D010087:Oxides; D010165:Palladium; D012996:Solutions; D013440:Sulfides; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates; C048320:palladium oxide