Search

Abstract: A series of rod‐shaped polyoxometalates (POMs) [Bu4N]7[Mo6O18NC(CH2O)3MnMo6O18(OCH2)3CNMo6O18] and [Bu4N]7[ArNMo6O17NC(CH2O)3MnMo6O18(OCH2)3CNMo6O17NAr] (Ar=2,6‐dimethylphenyl, naphthyl and 1‐methylnaphthyl) were chosen to study the effects of cation–π interaction on macroionic self‐assembly. Diffusion ordered spectroscopy (DOSY) and isothermal titration calorimetry (ITC) techniques show that the binding affinity between the POMs and Zn2+ ions is enhanced significantly after grafting aromatic groups onto the clusters, leading to the effective replacement of tetrabutylammonium counterions (TBAs) upon the addition of ZnCl2. The incorporation of aromatic groups results in the significant contribution of cation–π interaction to the self‐assembly, as confirmed by the opposite trend of assembly size vs. ionic strength when compared with those without aromatic groups. The small difference between two aromatic groups toward the Zn2+ ions is amplified after combining with the clusters, which consequently triggers the self‐recognition behavior between two highly similar macroanions. [ABSTRACT FROM AUTHOR]

Abstract: The efficient evolution of hydrogen through electrocatalysis is considered a promising approach to the production of clean hydrogen fuel. Platinum (Pt)‐based materials are regarded as the most active hydrogen evolution reaction (HER) catalysts. However, the low abundance and high cost of Pt hinders the large‐scale application of these catalysts. Active, inexpensive, and earth‐abundant electrocatalysts to replace Pt‐based materials would be highly beneficial to the production of cost‐effective hydrogen energy. Herein, a novel organoimido‐derivatized heteropolyoxometalate, Mo4‐CNP, is designed as a precursor for electrocatalysts of the HER. It is demonstrated that the carbon, nitrogen, and phosphorus sources derived from the Mo4‐CNP molecules lead to in situ confined carburization, phosphorization, and chemical doping on an atomic scale, thus forming nitrogen‐doped porous molybdenum carbide and phosphide hybrids, which exhibit remarkable electrocatalytic activity for the HER. Such an organically functionalized polyoxometalate‐assisted strategy described here provides a new perspective for the development of highly active non‐noble metal electrocatalysts for hydrogen evolution. [ABSTRACT FROM AUTHOR]

Several novel triol-ligands functionalized Anderson–Evans type polyoxotungstates, K3Na3[{HOCH2C(CH2O)3}AlO3W6O18], K3Na3[{HOCH2C(CH2O)3}CrO3W6O18], K3Na3[{HOCH2C(CH2O)3}CoO3W6O18], and K3Na3[{H3CC(CH2O)3}CoO3W6O18], were successfully synthesized and characterized, in which some of the central metal ions have never been found in the Anderson-type polyoxotungstates. The single crystal X-ray diffraction analysis indicated that the clusters were on a status, in which only one-side μ3-O was protonated. This indicates that the three-protonated cluster is a common type of Anderson cluster aside zero-protonated (A-type) and six-protonated (B-type), which could be named as the T-type. [ABSTRACT FROM AUTHOR]

On the basis of the well-developed N, N′-dicyclohexylcarbodiimide (DCC) imidoylization strategy, the novel trans-dinitrosyl-substituted polyoxometalate (POM) (NBu4)4[Mo6O17(≡NO)2] was synthesized in moderate yield with high purity through a highly selective reaction route under mild reaction conditions. Its structure was elucidated by IR and UV/Vis spectroscopy, ESI-MS, and single-crystal X-ray diffraction studies. Furthermore, its ability to undergo controlled NO release was confirmed by ESI-MS, and a curve of the amount of NO released as a function of time within a simulated body fluid system was obtained by UV spectroscopy. The rate of NO release is controlled by changing the pH of the system. This is the first time that the decomposition of a POM has been used to produce therapeutic NO species. This study provides a new route to controlled-release technology for NO storage and targeted delivery. [ABSTRACT FROM AUTHOR]

Abstract: The hexamolybdate cluster has been functionalized with fluorine-containing aromatic amine by the DCC (N,N′-dicyclohexylcarbodiimide) dehydrating protocol and two novel mono-functionalized arylimido derivatives of hexamolybdates bearing the electron-withdrawing trifluoromethyl group and trifluoromethoxy group, (Bu4N)2[Mo6O18(≡NAr)] (Ar= o-CF3C6H4) 1 and (Bu4N)2[Mo6O18(≡NAr)] (Ar= p-OCF3C6H4) 2 have been synthesized by improved method. Complete assignments were achieved for the title compounds by elemental analysis, IR, 1H NMR, UV/visible and single-crystal X-ray diffraction analyses. The preliminary herbicidal activity test indicated that they have some herbicidal activities. [Copyright &y& Elsevier]

Abstract: A bicapped Keggin anion-supported cobalt–phenanthroline complex (1) has been hydrothermally synthesized and structurally characterized by elemental analyses, single crystal X-ray diffraction and IR spectrum. Interestingly, all the polyanions constitute an anionic layer, while all the polycations are linked to form a cationic layer by the hydrogen bonding interactions. The result of magnetic measurement for compound 1 shows a typical antiferromagnetic interactions in the 2–300K temperature range. [Copyright &y& Elsevier]

Abstract: A novel polyoxometalate-based organic–inorganic hybrid compound, [Co(bpy)3]2 [Mo6O19] [β-(H2Mo8O26)]·4H2O (1), have been hydrothermally synthesized and structurally characterized by elemental analysis, single-crystal X-ray diffraction, IR and X-ray photoelectron spectra. Compound 1 represents the first example that racemic complexes coexisting with two kinds of polyoxomolybdate anions in the same crystal architecture, which should be of rare chance that four kinds of complexes crystallizes into a compound. [Copyright &y& Elsevier]