A Supramolecular Tetra‐Dawson Polyoxothiometalate: [(α‐H₂P₂W₁₅O₅₆)₄{Mo₂O₂S₂(H₂O)₂}₄{Mo₄S₄O₄(OH)₂(H₂O)}₂]²⁸⁻

Abstract

Fours for thought: The title compound was prepared by condensation of the preformed unit {Mo2O2S2}2+ as a linker on to the trivacant anion [α‐P2W15O5]12−. The self‐assembled structure exhibits a modular arrangement (see structure). 31P and 183W NMR spectroscopy revealed that the structure of the supramolecular tetra‐unit anion was maintained in solution.

Oxothiomolybdenum Derivatives of the Superlacunary Crown Heteropolyanion {P8W48}: Structure of [K4{Mo4O4S4(H2O)3(OH)2}2(WO2)(P8W48O184)]30– and Studies in Solution

“…In addition, the coordination sphere of the two peripheral Mo atoms of the tetranuclear arch is completed by a terminal inward directed aquo ligand (Mo···OH 2 = 2.331 Å) to give octahedral Mo­(V) centers. Such a tetranuclear fragment was already observed in the supramolecular assembly formed by combination of [Mo 2 O 2 S 2 ] 2+ and P 2 W 15 and in the coordination compound [Mo 4 S 4 O 4 (OH) 2 (H 2 O) 3 (pba)] 2– . The molecular structure of 1 closely ressembles the fully oxo analogue previously described by Müller et al, which represents the unique example where the oxo cation {Mo 2 O 4 } 2+ exhibits a similar mode of junction as those usually observed for the oxothio {Mo 2 O 2 S 2 }-based molecules.…”

“…The results obtained at pH = 3 are shown in Figure , whereas titrations at pH = 1.5 and 4.7 are shown in the Supporting Information (Figures S7 and S8). Absorptions in the 420–500 nm range are characteristic of the red-brown thioderivatives of POMs ,,− since {Mo 2 O 2 S 2 }-based species and P 8 W 48 alone do not exhibit significant absorptions in this region. Gradual addition of P 8 W 48 to a constant quantity of [Mo 2 O 2 S 2 ] 2+ leads to gradual increasing of the absorbance in this region until a break point at P 8 W 48 /[Mo 2 O 2 S 2 ] 2+ = 1/4, consistent with the stoichiometry of the saturated complex (Figure b).…”

“…The dinuclear cation [Mo 2 O 2 S 2 (H 2 O) 6 ] 2+ exhibits coordination requirements restricted to three available sites on each molybdenum center, thus allowing one to develop predictable POM–{Mo 2 O 2 S 2 } based coordination chemistry. The oxothiocation has been proved to react with basic lacunary POMs such as PW 9 , AsW 9 , SiW 10 , PW 10 , PW 11 , P 2 W 15 , and P 2 W 17 to give species ranging from monomeric to tetramodular assembly.…”

Three-Dimensional Interpenetrating Frameworks Based on {P4Mo6} Tetrameric Clusters and Filled with In Situ Generated Alkyl Viologens

“…As a significant member of the polyoxomolybdate library, [P 4 Mo 6 O 31 ] 12– (denoted as {P 4 Mo 6 }) demonstrates the following advantages: (i) it possesses many coordination sites where the Mo–O bonds can interact with the metal cation to form stable dimers and the P–O bonds can provide versatile coordination sites to various linking units; (ii) the {P 4 Mo 6 } units can facilitate multidirectional coordination connections to connect one or both metal ions, thus forming novel compounds with numerous topological structures and excellent properties. Various research works were devoted to the assembly of poly­(oxomolybdophosphate) anions into one-dimensional (1-D) polymers, − two-dimensional (2-D) structures, − and three-dimensional (3-D) microporous frameworks. − Hitherto, the trimeric/tetrameric species and high-dimensional structures were obtained using the Keggin/Dawson fragments, − while only a few examples based on {P 4 Mo 6 } are available. − As reported, the {P 4 Mo 6 } tetrameric clusters combined with transition metal complexes generally use H 3 PO 4 /Na 3 PO 4 and Na 2 MoO 4 /MoO 3 as their phosphorus and molybdenum sources and molybdenum powder, phosphite, and organic N-containing ligands as their reductants …”