title: Oxothiomolybdenum derivatives of the superlacunary crown heteropolyanion {P8W48}: structure of [K4{Mo4O4S4(H2O)3(OH)2}2(WO2)(P8W48O184)]30– and studies in solution.
abstract: Reaction of the cyclic lacunary [H(7)P(8)W(48)O(184)](33-) anion (noted P(8)W(48)) with the [Mo(2)S(2)O(2)(H(2)O)(6)](2+) oxothiocation led to two compounds, namely, [K(4){Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(WO(2))(P(8)W(48)O(184))](30-) (denoted 1) and [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(P(8)W(48)O(184))](36-) (denoted 2), which were characterized in the solid state and  solution. In the solid state, the structure of [K(4){Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(WO(2))(P(8)W(48)O(184))](30-) reveals the presence of two disordered {Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2+) "handles" connected on both sides of the P(8)W(48) ring. Such a disorder is consistent with the presence of two geometrical isomers where the relative disposition of the two {Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2+) handles are arranged in a perpendicular or parallel mode. Such an interpretation is fully supported by (31)P and (183)W NMR solution studies. The relative stability of both geometrical isomers appears to be dependent upon the nature of the internal alkali cations, i.e., Na(+) vs K(+), and increased lability of the two {Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2+) handles, compared to the oxo analogous, was clearly identified by significant broadening of the (31)P and (183)W NMR lines. Solution studies carried out by UV-vis spectroscopy showed that  formation of the adduct [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(P(8)W(48)O(184))](36-) occurs in the 1.5-4.7 pH range and corresponds to a fast and quantitative condensation process. Furthermore, (31)P NMR titrations in solution reveal  formation of the "monohandle" derivative [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(P(8)W(48)O(184))](38-) as an intermediate prior to  formation of the "bishandle" derivatives. Furthermore, the electrochemical behavior of [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(P(8)W(48)O(184))](36-) was studied in aqueous medium and compared with the parent anion P(8)W(48).
authors.affiliation: Institut Lavoisier de Versailles, UMR 8180, University of Versailles, 45 avenue des Etats-Unis, 78035 Versailles, France.
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Korenev
authors.forename: Sébastien
authors.initials: S
authors.lastname: Floquet
authors.forename: Jérôme
authors.initials: J
authors.lastname: Marrot
authors.forename: Mohamed
authors.initials: M
authors.lastname: Haouas
authors.forename: Israël-Martyr
authors.initials: IM
authors.lastname: Mbomekallé
authors.forename: Francis
authors.initials: F
authors.lastname: Taulelle
authors.forename: Maxim N
authors.initials: MN
authors.lastname: Sokolov
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Fedin
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Cadot
mesh_terms: D047248:Crown Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008982:Molybdenum / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry
chemical_list: D047248:Crown Compounds; D008982:Molybdenum; D009942:Organometallic Compounds; D010100:Oxygen; D000071228:Polyelectrolytes; D011108:Polymers; D013438:Sulfhydryl Compounds; D017973:Tungsten Compounds