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One halide ion (X−) can bind on the surface of nanoscale Anderson‐type polyoxometalate (POMs) clusters [(n‐C4H9)4N]3{AlMo6O18(OH)3[(OCH2)3CCH3]}, and form stable complexes in solution with binding constant K=1.53×103. Single‐crystal structural analysis showed that this binding behavior occurs through multiple hydrogen bonding between X− and three hydroxy groups on the uncapped side of the cluster. This supramolecular interaction in the cluster systems means that their catalytic activities, evaluated from the oxidation of alcohols to aldehydes, can be switched upon the introduction of halide ions and water molecules. The halide ions work as inhibitors by blocking the active sites of the clusters while they can be re‐activated by the addition of water. [ABSTRACT FROM AUTHOR]

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]

Cover Feature: Unprecedented Halide-Ion Binding and Catalytic Activity of Nanoscale Anionic Metal Oxide Clusters (ChemPlusChem 11/2019) B The cover feature b shows that halide ions can bind on the surface of nanoscale, anionic metal oxide clusters and form stable complexes in solution. Anion binding, heterogeneous catalysis, clusters, hydrogen bonding, polyoxometalates. [Extracted from the article]

Abstract: Two lanthanide-decorated polyoxometalates K[Ln2(α-SiW11O39)(H2O)11] (Ln=La, Ce) have been successfully synthesized and characterized with single-crystal X-ray diffraction, IR spectroscopy and thermogravimetric analysis. The two compounds have analogy structures, which consist of one-dimensional chains based on [α-SiW11O39]8− building blocks. The chains are further connected to a two-dimensional layer by potassium ions. The magnetic studies of compound 1 demonstrate a ferromagnetic interaction in 1. [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]

A novel bifunctionalized arylimido derivative of hexamolybdate, (Bu4N)2[Mo6O17(&z.tbnd6;NAr)2]2− (Ar=o-CH3C6H4) 1, in which the two o-tolylimido groups are bounded to hexamolybdate at the cis positions, was synthesized by self-assembled metathesis of α-type octamolybdate ion and o-toluidine with DCC as a dehydration agent. The most interesting characteristic of 1 is that the cluster anions form dimers via the π–π stacking between one of its two phenyl rings, and four such dimers are linked in turn via C–H⋯O hydrogen bonding involving terminal hexamolybdate oxygen atoms into ring-like tetramers in the solid state. [Copyright &y& Elsevier]

Abstract: A new disubstituted imido derivative [Bu4N]2[Mo6O17(NAr)2] (1) (Ar=2,4-(CH3)2C6H3), has been synthesized under a mild and convenient reflux reaction of [Bu4N]2[Mo6O19], 2,4-dimethylaniline, and DCC, and characterized by IR spectroscopy, elemental analysis, UV–vis absorption spectroscopy, and single-crystal X-ray diffraction. The most interesting characteristic of 1 is that its anion segment is linear and centrosymmetric with two imido groups occupying two terminal positions of hexamolybdate in an unusual trans fashion. This is the first trans-bis(imido)hexamolybdate prepared via a convenient synthetic route. [Copyright &y& Elsevier]