Building block libraries and structural considerations in the self-assembly of polyoxometalate and polyoxothiometalate systems

Inorganic metal-oxide clusters form a class of compounds that are unique in their topological and electronic versatility and are becoming increasingly more important in a variety of applications. Namely, Polyoxometalates (POMs) have shown an unmatched range of physical properties and the ability to form structures that can bridge several length scales. The formation of these molecular clusters is often ambiguous and is governed by self-assembly processes that limit our ability to rationally design such molecules. However, recent years have shown that by considering new building block principles the design and discovery of novel complex clusters is aiding our understanding of this process. Now with current progress in thiometalate chemistry, specifically polyoxothiometalates (POTM), the field of inorganic molecular clusters has further diversified allowing for the targeted development of molecules with specific functionality. This chapter discusses the main differences between POM and POTM systems and how this affects synthetic methodologies and reactivities. We will illustrate how careful structural considerations can lead to the generation of novel building blocks and further deepen our understanding of complex systems

Addition of {M2S2O2}(2+), M = Mo, W, to A-alpha-[PW9O34](9-). Synthesis and structural characterizations in the solid state and in solution

Bereau V, Cadot E, Bögge H, Müller A, Secheresse F. Addition of {M2S2O2}(2+), M = Mo, W, to A-alpha-[PW9O34](9-). Synthesis and structural characterizations in the solid state and in solution. INORGANIC CHEMISTRY. 1999;38(25):5803-5808.The [P2W18M6S6O74(H2O)(6)](12-) anions, M = Mo, W, were obtained through the stereospecific addition of the dithiocation [M2O2S2](2+) to the trivacant A-alpha-[PW9O34](9-). K-12[P2W18Mo6S6O74(H2O)(6)]. 26H(2)O has been isolated as crystals and has been characterized by X-ray diffraction (orthorhombic Pmn2(I) with a = 31.530(6) Angstrom, b = 19.703(4) Angstrom, c = 18.761(4) Angstrom, Z = 4). The structure of the anion consists of a sandwich-like arrangement of two alpha-[PW9O34](9-) subunits bridged by three [Mo2O2S2(H2O)(2)] cores. The X-ray diffraction structural analysis showed that one [Mo2O2S2] bridging unit was rotated through an angle of 180 degrees with respect to the other two. Among the six water molecules attached to the Mo centers, four are directed toward the inner cavity while the two remaining ones are directed out of the cavity. According to the X-ray data, W-183 NMR characterizations of both compounds show the lowering of the local symmetry of the alpha-[PW9O34](9-) subunit from C-3v to C-s. For [P2W24S6O74(H2O)(6)](12-) two additional deshielded resonances were observed characteristic of the distribution of the three [W2O2S2(H2O)(2)] bridging units. Infrared data are also given

Mo-V-Mo-VI mixed valence polyoxometalates for facile synthesis of stabilized metal nanoparticles: Electrocatalytic oxidation of alcohols

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