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The complex {Na2(H2O)8[GdCu5(GlyHA)5(H2O)4L]2}L2 ⋅ 2.5DMF ⋅ 10.5H2O (1, where GlyHA2−= glycinehydroxamate, L2−= 4,4′‐bis(2‐sulfonatostyryl)biphenyl) was obtained as the outcome of the metathesis reaction of previously reported [GdCu5(GlyHA)5(CO3)(NO3)(H2O)5] ⋅ 3.5H2O with an excess of the disulfonate's sodium salt. X‐Ray analysis of 1 shows a dimeric structure in which 15‐metallacrown‐5 units {GdCu5}3+ are arranged in an "edge‐to‐edge" manner by way of two linking disulfonates, L2−. Magnetic studies of polycrystalline 1 over a temperature range of 2–300 K revealed both Gd‐Cu ferromagnetic and Cu‐Cu antiferromagnetic interactions within the metallacrown unit. Experimental χMT vs. T data for 1 were fitted using different theoretical models. A two‐J model, which takes into account both exchange interactions between adjacent copper(II) ions and the Gd‐Cu exchange interactions allows fitting of the χMT vs. T data in the whole temperature range. The values obtained for the exchange parameters are in accord with previously reported parameters for Ln(III)‐Cu(II) 15‐metallacrowns‐5. The 240 GHz powder EPR spectra for 1 were recorded between 30 and 150 K. [ABSTRACT FROM AUTHOR]

The aim of the paper was to synthesize Mn/Ca entities that are structurally similar to the reported oxygen‐evolving complex (OEC) of photosystem II (PSII). Here we have ventured Schiff base combinations of racemic (±)‐3‐Aminopropane‐1,2‐diol and Salicyladehyde (H3L1)/o‐Vanillin (H3L2) with varied ratios of ligand : CaIIsalt : MnIIIsalt. Interestingly, H3L2 : CaCl2 : MnCl2 (2 : 1 : 1) afforded [{MnIII2CaII2(HL2)2Cl2(μ3‐OH)2(H2O)6}Cl2 ⋅ 2H2O] (3) whereas H3L1 : CaCl2 : Mn(acetate)2 (2 : 1 : 1) and H3L1 : CaCl2 : MnCl2 (2 : 1 : 2), generated [{MnIV(HL1)2}2 ⋅ 6H2O](1) and [{MnIII3MnII(HL1)3(μ2‐Cl)3(μ3‐O)} ⋅ 2CH3OH ⋅ 2H2O] (2) respectively. More importantly, we have been able to get a structure which offers partial similarity to reported structure of the OEC. Variable temperature magnetic susceptibility measurements have been performed in the 1.8–30 K region for all the compounds. Overall, these studies provide a critical understanding for the rational design and construction of synthetic OEC. [ABSTRACT FROM AUTHOR]

Interaction of the trilacunary 9-tungstosilicate [A-α-SiW9O34]10− with cobalt(II), nickel(II) and zinc(II) ions in pH 9 aqueous medium at room temperature led to the formation of the respective M4-containing heteropolytungstates [M4(OH)3(H2O)2(α-SiW10O36.5)2]13− (M = Co2+ (1), Ni2+ (2), and Zn2+ (3)). Polyanions 1–3 were characterized in the solid state by single-crystal XRD, FT-IR spectroscopy, and thermogravimetric and elemental analyses. Electrochemical studies showed that the Co2+ ions in 1 can be oxidized to Co3+ and the CVs of the WVI centers of the polyanions feature well-defined and chemically reversible reduction waves. Magnetic measurements on 1 and 2 showed paramagnetism with complex ferromagnetic and antiferromagnetic interactions. A model was presented for extracting the exchange constants for the magnetic exchange interaction. [ABSTRACT FROM AUTHOR]

NH4CuCl3, a well-studied antiferromagnet best known for its gapless magnetization and unusual magnetization plateaus, is shown here to exhibit magnetoelectric behavior below the antiferromagnetic transition temperature of 1.3 K. This is based on magnetic field and temperature dependent capacitance measurements made at millikelvin temperatures, along with the appearance of spontaneous polarization and electric-field reversible pyroelectric current. The possession of both long-range magnetic and dielectric order, combined with magnetoelectric coupling, renders this material a rather unique Cu-based multiferroic and serves as a unique template for the design of such materials. [ABSTRACT FROM AUTHOR]

NH4CuCl3, a well-studied antiferromagnet best known for its gapless magnetization and unusual magnetization plateaus, is shown here to exhibit magnetoelectric behavior below the antiferromagnetic transition temperature of 1.3 K. This is based on magnetic field and temperature dependent capacitance measurements made at millikelvin temperatures, along with the appearance of spontaneous polarization and electric-field reversible pyroelectric current. The possession of both long-range magnetic and dielectric order, combined with magnetoelectric coupling, renders this material a rather unique Cu-based multiferroic and serves as a unique template for the design of such materials. [ABSTRACT FROM AUTHOR]

Ammonium trichlorocuprate, NH4CuCl3, a member of the family of quantum antiferromagnets M3CuCl3(M = K,Tl,NH+4), well known for its gapless magnetization with unusual plateaus, is shown here to exhibit ferroelectricity below 67 K based on anomalies of the specific heat and dielectric constant, along with the appearance of spontaneous polarization and electric-field reversible pyroelectric current, making it a rare example of a Cu(II)-based ferroelectric. This suggests that the general M3CuCl3 family could be rendered multiferroic by alloying its alkali metals with NH+4 ions. [ABSTRACT FROM AUTHOR]

Interaction of the trilacunary 9-tungstosilicate [A-α-SiW9O34]10− with cobalt(II), nickel(II) and zinc(II) ions in pH 9 aqueous medium at room temperature led to the formation of the respective M4-containing heteropolytungstates [M4(OH)3(H2O)2(α-SiW10O36.5)2]13− (M = Co2+ (1), Ni2+ (2), and Zn2+ (3)). Polyanions 1–3 were characterized in the solid state by single-crystal XRD, FT-IR spectroscopy, and thermogravimetric and elemental analyses. Electrochemical studies showed that the Co2+ ions in 1 can be oxidized to Co3+ and the CVs of the WVI centers of the polyanions feature well-defined and chemically reversible reduction waves. Magnetic measurements on 1 and 2 showed paramagnetism with complex ferromagnetic and antiferromagnetic interactions. A model was presented for extracting the exchange constants for the magnetic exchange interaction. [ABSTRACT FROM AUTHOR]

Anhydrous plutonium tetrafluoride is an important intermediate in the production of metallic Pu. This historically important compound is also known to exist in at least two distinct, yet understudied hydrate forms, PuF 4 · x H 2 O(s) (0.5 ≤ x ≤ 2) and PuF 4 ·2.5H 2 O(s). X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) are the most common tools used to characterize these materials, often in a context for studying structural and morphological changes that arise from aging or calcination. However, fundamental electronic and vibrational spectroscopic information is rather scarce. Here, we measured the visible and shortwave infrared (SWIR) diffuse reflectance, Fourier transform infrared (FTIR), fluorescence and Raman spectra of PuF 4 (s) and PuF 4 · x H 2 O(s) to obtain a better electronic and vibrational fingerprint. Our work provides clear indication of the polymeric structure of anhydrous PuF 4 , consistent with the Raman spectrum of UF 4 (s) and its hydrates. This is supplemented with XRD, TGA and SEM analysis. Findings in this study indicate that the spectra are modified by particle size, which in turn is influenced by synthetic technique.

A family of five host-guest assemblies comprising different metal ions inside a cuboid 12-palladium-oxo cage, [MO 8 Pd 12 L 8 ] n - ( MPd 12 L 8 , M = Sc III , Co II , Cu II , L = AsO 4 3- ; M = Cd II , Hg II , L = PhAsO 3 2- ), was synthesized and structurally characterized in the solid state by single-crystal X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis, and their solution and gas-phase stability were validated by multinuclear NMR spectroscopy and electrospray-ionization mass spectrometry (ESI-MS). The polyoxopalladates (POPs) ScPd 12 As 8 , CoPd 12 As 8 , and CuPd 12 As 8 represent the first three examples of the MPd 12 As 8 archetype. The unique cubic ligand field of {MO 8 } allows for collecting the speciation profiles of the POPs in solution using 45 Sc and 113 Cd NMR techniques. Detailed magnetic and electron paramagnetic resonance (EPR) studies were performed on CuPd 12 As 8 . Catalytic studies on MPd 12 As 8 (M = Cu II and Co II ) supported on SBA-15 unveiled a guest metal-dependent structure-function relationship, with CuPd 12 As 8 being the more efficient precatalyst for the hydroconversion of o -xylene in a fixed-bed reactor.

Six arsenic(III)-capped 12-tungsto-2-arsenates(III) of the type [M 2 (As III W 6 O 25 ) 2 (As III OH) x ] n - (M = Cr III , 1 ; Fe III , 2 ; Sc III , 3 ; In III , 4 ; Ti IV , 5 ; Mn II , 6 ) have been synthesized in aqueous medium by direct reaction of the elements using a one-pot strategy and structurally characterized by FT-IR spectroscopy, single-crystal XRD, and elemental analysis. Polyanions 1 - 6 are comprised of two octahedrally coordinated guest metal ions M sandwiched between two {AsW 6 } units, resulting in a structure with C 2 h point-group symmetry. Polyanions 1 - 5 contain tri- and tetravalent metal ion guests M (M = Cr III , Fe III , Sc III , In III , and Ti IV , respectively), and they have one {As III OH} group grafted on each {AsW 6 } unit, whereas the divalent Mn II -containing derivative 6 has two such {As III OH} groups grafted on each {AsW 6 } unit. Magnetic studies on polyanions 3 - 5 over the temperature range 1.8-295 K and magnetic fields of 0-7 T confirmed that they are diamagnetic. On the other hand, polyanions 1 , 2 , and 6 are strongly magnetic and follow the Curie-Weiss law above 30 K. The susceptibility plots of 1 and 6 exhibit broad peaks suggesting short-range antiferromagnetic ordering, while the very weak antiferromagnetic ordering of 2 is overshadowed by traces of a paramagnetic impurity. The magnetization data of 1 , 2 , and 6 at 1.8 K over 0-7 T were analyzed by using the Heisenberg exchange procedure. Small (negative) values of the obtained J values help in understanding the absence of long-range antiferromagnetic ordering.

Interaction of the trilacunary 9-tungstosilicate [A-α-SiW 9 O 34 ] 10- with cobalt(ii), nickel(ii) and zinc(ii) ions in pH 9 aqueous medium at room temperature led to the formation of the respective M 4 -containing heteropolytungstates [M 4 (OH) 3 (H 2 O) 2 (α-SiW 10 O 36.5 ) 2 ] 13- (M = Co 2+ (1), Ni 2+ (2), and Zn 2+ (3)). Polyanions 1-3 were characterized in the solid state by single-crystal XRD, FT-IR spectroscopy, and thermogravimetric and elemental analyses. Electrochemical studies showed that the Co 2+ ions in 1 can be oxidized to Co 3+ and the CVs of the W VI centers of the polyanions feature well-defined and chemically reversible reduction waves. Magnetic measurements on 1 and 2 showed paramagnetism with complex ferromagnetic and antiferromagnetic interactions. A model was presented for extracting the exchange constants for the magnetic exchange interaction.

Reaction of the mixed-valent Mn 12 -acetato complex [Mn III 8 Mn IV 4 O 12 (CH 3 COO) 16 (H 2 O) 4 ] with the trilacunary Wells-Dawson-type heteropolytungstate [P 2 W 15 O 56 ] 12- in acidic acetate solution (pH 1.1) resulted in the tetra-Mn III -containing polyanion [Mn III 4 (H 2 O) 2 (P 2 W 15 O 56 ) 2 ] 12- ( 1 ). Single-crystal XRD on Na 12 [Mn III 4 (H 2 O) 2 (P 2 W 15 O 56 ) 2 ]·84H 2 O ( 1a ) revealed that four Mn III ions form a rhombic Mn 4 O 16 core encapsulated by two [P 2 W 15 O 56 ] 12- units. X-ray photoelectron spectroscopy (XPS) data confirm the +3 oxidation state of the four manganese ions in 1 . Magnetic measurements from 1.8-300 K in a 100 Oe magnetic field allowed for the extraction of full fitting parameters from the susceptibility data for 1 . The negative J a value ( J a = -2.16 ± 0.08 K, J b = 3.24 ± 1.73 K, g = 2.35 ± 0.040, and ρ = 0.34 ± 0.03) suggests a dominant antiferromagnetic spin exchange interaction between the four Mn III ions, with the positive J b being an accompanying result of J a . Electrochemical studies revealed a reversible Mn IV /Mn III redox couple in 1 at the +0.80 to +1.1 V potential region with E 1/2 = +0.907 V.