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Two new YIII containing sandwich‐type heterometallic tungstophosphates: [Y{PM2W10O38(H2O)2}2]11– (M = CoII (1) and ZnII (2)) have been synthesized under mild reaction conditions. Both the molecular complexes 1 a and 2 a were synthesized by reacting Y(NO3)3⋅6H2O, M(NO3)2⋅6H2O (M = CoII and ZnII) with Wells‐Dawson type divacant K14[P2W19O69(H2O)]⋅24H2O precursor. The potassium salts of single crystalline material were collected and further used for characterization with different analytical techniques including single crystal X‐ray diffraction (SC‐XRD), Fourier transform infrared (FT‐IR) spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP‐AES), 31P, 183W and 89Y nuclear magnetic resonance (NMR) spectroscopy, high‐resolution electro‐spray ionization mass spectrometry (HR‐ESI‐MS) as well as thermogravimetric analysis. Single crystal X‐ray diffraction analysis shows that both polyanions crystallize in the orthorhombic crystal system with space group Iba2. Each polyanion consists of (1,5) isomer of di‐metal substituted α‐Keggin type tungstophosphates, which sandwiched a YIII ion. We have reported two new purely inorganic YIII containing di‐metal substituted sandwich‐type tungstophosphate nanoclusters [Y{PM2W10O38(H2O)2}2]11– (M=CoII (1) and ZnII (2)) followed by one pot reaction procedure under mild reaction conditions. Both compounds were well characterized with different analytical techniques. The polyanion 1 and 2 consist of two units of (1,5) isomers of di‐metal substituted hetero Keggin [PM2W10O38(H2O)2]7– anion, sandwiched by yttrium ion. [ABSTRACT FROM AUTHOR]

We report on the synthesis and structural characterization of four bismuth(III)‐containing sandwich‐type heteropolytungstates with Bi in 8‐coordination. The three isostructural Keggin‐type ions [Bi(α‐XW11O39)2]n– {X = Si (1), Ge (2), n = 13; X = P (3), n = 11} and the Wells–Dawson‐type ion [Bi(α2‐P2W17O61)2]17– (4) were prepared via simple one‐pot synthetic procedures in aqueous medium. The novel polyanions comprise a Bi3+ ion linking two monolacunary {XW11} or {X2W17} units in a sandwich‐type fashion. The Bi3+ ion is coordinated by four oxygens of each monolacunary POM unit, resulting in 8‐coordination with square‐antiprismatic geometry. Such a coordination mode is rare for Bi3+. We demonstrate that bismuth(III) can link two monolacunary Keggin‐ and Dawson‐type heteropolytungstates resulting in sandwich‐type structures with 8‐coordinated bismuth(III) in square‐antiprismatic coordination geometry. The four novel polyanions were characterized in the solid state and in solution. [ABSTRACT FROM AUTHOR]

The 15-copper(ii)-containing 36-tungsto-4-silicates [Cu15O2(OH)10X(A-α-SiW9O34)4]25− (X = Cl, 1; Br, 2) have been prepared in 70% yield by reaction of the trilacunary 9-tungstosilicate precursor [A-α-SiW9O34]10− with Cu2+ ions in aqueous pH 8 medium. Both polyanions 1 and 2 were isolated as hydrated mixed potassium/sodium salts and characterized in the solid state by FT-IR, TGA, single-crystal XRD, and elemental analysis. DC magnetic susceptibility measurements from 1.8–300 K established the ground state to be paramagnetic with a magnetic moment corresponding to 15 uncoupled Cu2+ (S = 1/2) ions. EPR measurements and simulations were consistent with this analysis. Electrochemical studies were performed for polyanions 1 and 2 dissolved in solution to elucidate the electroactivity of both copper and tungstate sites. Using 2 as a representative example, the electrocatalytic activity towards CO2 reduction upon deposition on a glassy carbon electrode surface, while retaining selectivity relative to hydrogen evolution, was demonstrated. [ABSTRACT FROM AUTHOR]

The Preyssler‐Pope‐Jeannin polyanion [NaP5W30O110]14– (1) was prepared by microwave‐assisted synthesis in only 2 h with a yield comparable to the reported hydrothermal procedure. The purity of 1 was confirmed by FT‐IR and multinuclear NMR (31P, 183W) analysis. The silver(I)‐containing analogue [AgP5W30O110]14– (2) was also prepared by hydrothermal (6 d) as well as microwave‐based (2 h) procedures. Polyanion 2 was characterized in the solid state by FT‐IR, single‐crystal XRD, TGA, and elemental analysis and in solution by 31P and 183W NMR, and ESI‐MS. The antiproliferative activities against human cells as well as the antimicrobial properties towards Gram‐positive and Gram‐negative bacteria were comparatively evaluated for 1 and 2. [ABSTRACT FROM AUTHOR]

Abstract: Electrocatalytic reduction of water, also known as the hydrogen evolution reaction (HER), may be one of the solutions for a sustainable energy supply in the future, but the current use of precious platinum electrocatalysts is a major drawback, owing to the high cost. So, it is urgent to discover cost‐effective and earth‐abundant materials to replace precious‐metal electrocatalysts in order to make this technology economically viable. Herein, we report the preparation and application of three new nanocomposites based on polyoxometalates (POMs) and reduced oxidized‐graphene flakes (rGF_ox) as HER electrocatalysts (ECs). In highly acidic medium (pH=0.3), the POM@rGF_ox ECs showed similar overpotentials (0.033–0.044 V vs. RHE) for a current density of 10 mA cm−2, and these are very close to the state‐of‐the‐art HER EC, 20 wt% Pt/C (0.024 V). The POM‐based nanocomposites also exhibited excellent exchange current densities (0.65–1.02 mA cm−2) and very low Tafel slopes (0.033–0.041 V dec−1). P5W30@rGF_ox exhibited the best HER metrics and also showed long‐term electrochemical stability, as the overpotential only changed 0.009 V for j=10 mA cm−2 after 1000 linear sweep voltammetry cycles. Besides highlighting POM‐oxidized‐graphene flakes composites as a new class of nanomaterial with several important electrochemical applications, this work also points out that the POM shape, size, charge, and composition (W/P ratio) may play an important role in fine‐tuning the HER activity, and opens new avenues for designing a new set of highly efficient, cost‐effective, and durable non‐precious‐metal HER ECs in acidic medium. [ABSTRACT FROM AUTHOR]

We have reinvestigated the dilacunary 19-tungsto-2-arsenate(III) [AsIII2W19O67(H2O)]14- ( 1), resulting in the mixed potassium-sodium salt K8Na6[AsIII2W19O67(H2O)] ·28H2O ( KNa-1), which was structurally characterized in the solid state by single-crystal XRD, IR, TGA, and elemental analysis, as well as in aqueous solution by 183W NMR spectroscopy for the first time. [ABSTRACT FROM AUTHOR]

We report on a fast microwave-assisted synthetic procedure of the Wells-Dawson-type 18-tungsto-2-phosphate [P2W18O62]6− with a 35% yield in 24 h, rather than a week using conventional heating. [ABSTRACT FROM AUTHOR]

Two new YIII containing sandwich‐type heterometallic tungstophosphates: [Y{PM2W10O38(H2O)2}2]11– (M = CoII (1) and ZnII (2)) have been synthesized under mild reaction conditions. Both the molecular complexes 1 a and 2 a were synthesized by reacting Y(NO3)3⋅6H2O, M(NO3)2⋅6H2O (M = CoII and ZnII) with Wells‐Dawson type divacant K14[P2W19O69(H2O)]⋅24H2O precursor. The potassium salts of single crystalline material were collected and further used for characterization with different analytical techniques including single crystal X‐ray diffraction (SC‐XRD), Fourier transform infrared (FT‐IR) spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP‐AES), 31P, 183W and 89Y nuclear magnetic resonance (NMR) spectroscopy, high‐resolution electro‐spray ionization mass spectrometry (HR‐ESI‐MS) as well as thermogravimetric analysis. Single crystal X‐ray diffraction analysis shows that both polyanions crystallize in the orthorhombic crystal system with space group Iba2. Each polyanion consists of (1,5) isomer of di‐metal substituted α‐Keggin type tungstophosphates, which sandwiched a YIII ion. We have reported two new purely inorganic YIII containing di‐metal substituted sandwich‐type tungstophosphate nanoclusters [Y{PM2W10O38(H2O)2}2]11– (M=CoII (1) and ZnII (2)) followed by one pot reaction procedure under mild reaction conditions. Both compounds were well characterized with different analytical techniques. The polyanion 1 and 2 consist of two units of (1,5) isomers of di‐metal substituted hetero Keggin [PM2W10O38(H2O)2]7– anion, sandwiched by yttrium ion. [ABSTRACT FROM AUTHOR]

We report on the synthesis and structural characterization of four bismuth(III)‐containing sandwich‐type heteropolytungstates with Bi in 8‐coordination. The three isostructural Keggin‐type ions [Bi(α‐XW11O39)2]n– {X = Si (1), Ge (2), n = 13; X = P (3), n = 11} and the Wells–Dawson‐type ion [Bi(α2‐P2W17O61)2]17– (4) were prepared via simple one‐pot synthetic procedures in aqueous medium. The novel polyanions comprise a Bi3+ ion linking two monolacunary {XW11} or {X2W17} units in a sandwich‐type fashion. The Bi3+ ion is coordinated by four oxygens of each monolacunary POM unit, resulting in 8‐coordination with square‐antiprismatic geometry. Such a coordination mode is rare for Bi3+. We demonstrate that bismuth(III) can link two monolacunary Keggin‐ and Dawson‐type heteropolytungstates resulting in sandwich‐type structures with 8‐coordinated bismuth(III) in square‐antiprismatic coordination geometry. The four novel polyanions were characterized in the solid state and in solution. [ABSTRACT FROM AUTHOR]

We have discovered the first polythioplatinate(II), [Pt II S 3 S 2 (SO 3 ) 6 ] 10- ( 1 ), which was synthesized in aqueous basic medium (pH 11) by hydrothermal heating at 150 °C. Polyanion 1 comprises a discrete, triangular assembly of three Pt 2+ -sulfido ligands, and their square-planar coordination geometry is completed by two terminal S-bound sulfito ligands. Polyanion 3 -sulfido ligands, and their square-planar coordination geometry is completed by two terminal S-bound sulfito ligands. Polyanion 1 was isolated as a hydrated sodium salt, Na 10 [Pt II -S) 3 (μ 3 -S) 2 (SO 3 ) 6 ]·22H 2 O ( Na-1 ), which was characterized in the solid state by single-crystal X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectra, and elemental analysis, in solution by 195 Pt NMR and atomic absorption spectroscopy, and in the gas phase by electrospray ionization mass spectrometry. Density functional theory calculations were performed, and the 195 Pt NMR chemical shifts of 1 were computed theoretically and shown to match well with the experimental data. Furthermore, the discrete title polyanion 1 was immobilized on mesoporous SBA-15 support and used as a precatalyst for the hydrogenation of o -xylene.

The synthesis of four organometallic RhCp*- and IrCp*-containing heteropoly-20-tungstates, [{RhCp*} 2 Bi 2 W 20 O 70 ] 10- ( 1 ), [{IrCp*} 2 Bi 2 W 20 O 70 ] 10- ( 2 ), [{RhCp*} 2 Sb 2 W 20 O 70 ] 10- ( 3 ), and [{IrCp*} 2 Sb 2 W 20 O 70 ] 10- ( 4 ) has been accomplished by reaction of (MCp*Cl 2 ) 2 with [X 2 W 22 O 74 (OH) 2 ] 12- in aqueous solution at pH 6 and 70 °C. The four polyanions 1 - 4 were structurally characterized in the solid state by single-crystal XRD, FTIR, and TGA and in solution by 183 W and 13 C NMR. For the Rh derivatives 1 and 3 the 183 W- 103 Rh coupling ( 2 J W-Rh 3.0 Hz) could be identified by 183 W NMR., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

We report on the synthesis and structural characterization of a giant, discrete, and neutral molecular disk, [Pd 40 O 24 (OH) 16 {(CH 3 ) 2 AsO 2 } 16 ] ( Pd 40 ), comprising a 40-palladium-oxo core that is capped by 16 dimethylarsinate moieties, resulting in a palladium-oxo cluster (POC) with a diameter of ∼2 nm. Pd 40 , which is the largest known neutral Pd-based oxo cluster, can be isolated either as a discrete species or constituting a 3D H-bonded organic-inorganic framework (HOIF) with a 12-tungstate Keggin ion, [SiW 12 O 40 ] 4- or [GeW 12 O 40 ] 4- . 1 H and 13 C NMR as well as 1 H-DOSY NMR studies indicate that Pd 40 is stable in aqueous solution, which is also confirmed by ESI-MS studies. Pd 40 was also immobilized on a mesoporous support (SBA15) followed by the generation of size-controlled Pd nanoparticles (diameter ∼2-6 nm, as based on HR-TEM), leading to an effective heterogeneous hydrogenation catalyst for the transformation of various arenes to saturated carbocycles.