eta Bis(ethylenediammonium) μ-ethylenediaminetetraacetato-1κ3O,N,O':2κ3O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate By journals.iucr.org Published On :: 2024-07-12 The title compound, (C2H10N2)2[(C10H12N2O8)(MoO3)2]·4H2O, which crystallizes in the monoclinic C2/c space group, was obtained by mixing molybdenum oxide, ethylenediamine and ethylenediaminetetraacetic acid (H4edta) in a 2:4:1 ratio. The complex anion contains two MoO3 units bridged by an edta4− anion. The midpoint of the central C—C bond of the edta4− anion is located on a crystallographic inversion centre. The independent Mo atom is tridentately coordinated by a nitrogen atom and two carboxylate groups of the edta4− ligand, together with the three oxo ligands, producing a distorted octahedral coordination environment. In the three-dimensional supramolecular crystal structure, the dinuclear anions, the organoammonium counter-ions and the solvent water molecules are linked by N—H⋯Ow, N—H⋯Oedta and O—H⋯O hydrogen bonds. Full Article text
eta Diisobutylammonium triphenyl(2-thiolatoacetato-κ2O,S)stannate(IV) By journals.iucr.org Published On :: 2024-08-09 Crystals of the title salt, (C8H20N)[Sn(C6H5)3(C2H2O2S)], comprise diisobutylammonium cations and mercaptoacetatotriphenylstannate(IV) anions. The bidentate binding mode of the mercaptoacetate ligand gives rise to a five-coordinated, ionic triphenyltin complex with a distorted cis-trigonal–bipyramidal geometry around the tin atom. In the crystal, charge-assisted ammonium-N—H⋯O(carboxylate) hydrogen-bonding connects two cations and two anions into a four-ion aggregate. Two positions were resolved for one of the phenyl rings with the major component having a site occupancy factor of 0.60 (3). Full Article text
eta Bis[μ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] By journals.iucr.org Published On :: 2024-08-30 The title compound, [Ni2(C8H6N3)2(C2H3O2)2(C5H8N2)2] or [Ni(μ-OOCCH3)(2-PyPz)(Me2PzH)]2 (1) [2-PyPz = 3-(pyridin-2-yl) pyrazole; Me2PzH = 3,5-dimethyl pyrazole] was synthesized from Ni(OOCCH3)2·4H2O, 2-PyPzH, Me2PzH and triethylamine as a base. Compound 1 {[Ni2(C30H34N10Ni2O4)]} at 100 K has monoclinic (P21/n) symmetry and the molecules have crystallographic inversion symmetry. Molecules of 1 comprise an almost planar dinuclear NiII core with an N4O2 coordination environment. The equatorial plane consists of N3,O coordination derived from one of the bidentate acetate O atoms and three of the N atoms of the chelating 2-PyPz ligand while the axial positions are occupied by neutral Me2PzH and the second O atom of the acetate unit. The Ni atoms are bridged by the nitrogen atom of a deprotonated 2-PyPz ligand. Compound 1 exhibits various inter- and intramolecular C—H⋯O and N—H⋯O hydrogen bonds. Full Article text
eta 2-Bromoacetamide By journals.iucr.org Published On :: 2024-09-30 The title compound, C2H4BrNO, crystallizes in the monoclinic space group P21/c with one molecule in the asymmetric unit. The almost planar molecules are organized via N—H⋯O hydrogen bonds into a ladder-type network, which can be characterized by the graph sets R22(8) and R24(8). In addition, the molecules are connected by C—H⋯O and C—H⋯Br contacts. Full Article text
eta 2-Chloro-N-(4-hydroxyphenyl)acetamide By journals.iucr.org Published On :: 2024-10-24 The title compound, C8H8ClNO2, is significantly distorted from planarity, with a twist angle between the planes through the hydroxybenzene and acetamide groups being 23.5 (2)°. This conformation is supported by intramolecular C—H⋯O and N—H⋯Cl contacts. In the crystal, N—H⋯O hydrogen-bonding contacts between acetamide groups and O—H⋯O contacts between hydroxyl groups form tapes propagating parallel to [103]. Full Article text
eta Synthesis, characterization and structural analysis of complexes from 2,2':6',2''-terpyridine derivatives with transition metals By journals.iucr.org Published On :: 2024-05-16 The synthesis and structural characterization of three families of coordination complexes synthesized from 4'-phenyl-2,2':6',2''-terpyridine (8, Ph-TPY), 4'-(4-chlorophenyl)-2,2':6',2''-terpyridine (9, ClPh-TPY) and 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (10, MeOPh-TPY) ligands with the divalent metals Co2+, Fe2+, Mn2+ and Ni2+ are reported. The compounds were synthesized from a 1:2 mixture of the metal and ligand, resulting in a series of complexes with the general formula [M(R-TPY)2](ClO4)2 (where M = Co2+, Fe2+, Mn2+ and Ni2+, and R-TPY = Ph-TPY, ClPh-TPY and MeOPh-TPY). The general formula and structural and supramolecular features were determinated by single-crystal X-ray diffraction for bis(4'-phenyl-2,2':6',2''-terpyridine)nickel(II) bis(perchlorate), [Ni(C21H15N3)2](ClO4)2 or [Ni(Ph-TPY)2](ClO4)2, bis[4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine]manganese(II) bis(perchlorate), [Mn(C22H17N3O)2](ClO4)2 or [Mn(MeOPh-TPY)2](ClO4)2, and bis(4'-phenyl-2,2':6',2''-terpyridine)manganese(II) bis(perchlorate), [Mn(C21H15N3)2](ClO4)2 or [Mn(Ph-TPY)2](ClO4)2. In all three cases, the complexes present distorted octahedral coordination polyhedra and the crystal packing is determined mainly by weak C—H⋯π interactions. All the compounds (except for the Ni derivatives, for which FT–IR, UV–Vis and thermal analysis are reported) were fully characterized by spectroscopic (FT–IR, UV–Vis and NMR spectroscopy) and thermal (TGA–DSC, thermogravimetric analysis–differential scanning calorimetry) methods. Full Article text
eta Salt forms of amides: protonation of acetanilide By journals.iucr.org Published On :: 2024-08-06 Treating the amide acetanilide (N-phenylacetamide, C8H9NO) with aqueous strong acids allowed the structures of five hemi-protonated salt forms of acetanilide to be elucidated. N-(1-Hydroxyethylidene)anilinium chloride–N-phenylacetamide (1/1), [(C8H9NO)2H][Cl], and the bromide, [(C8H9NO)2H][Br], triiodide, [(C8H9NO)2H][I3], tetrafluoroborate, [(C8H9NO)2H][BF4], and diiodobromide hemi(diiodine), [(C8H9NO)2H][I2Br]·0.5I2, analogues all feature centrosymmetric dimeric units linked by O—H⋯O hydrogen bonds that extend into one-dimensional hydrogen-bonded chains through N—H⋯X interactions, where X is the halide atom of the anion. Protonation occurs at the amide O atom and results in systematic lengthening of the C=O bond and a corresponding shortening of the C—N bond. The size of these geometric changes is similar to those found for hemi-protonated paracetamol structures, but less than those in fully protonated paracetamol structures. The bond angles of the amide fragments are also found to change on protonation, but these angular changes are also influenced by conformation, namely, whether the amide group is coplanar with the phenyl ring or twisted out of plane. Full Article text
eta Coordination structure and intermolecular interactions in copper(II) acetate complexes with 1,10-phenanthroline and 2,2'-bipyridine By journals.iucr.org Published On :: 2024-08-23 The crystal structures of two coordination compounds, (acetato-κO)(2,2'-bipyridine-κ2N,N')(1,10-phenanthroline-κ2N,N')copper(II) acetate hexahydrate, [Cu(C2H3O2)(C10H8N2)(C12H8N2)](C2H3O2)·6H2O or [Cu(bipy)(phen)Ac]Ac·6H2O, and (acetato-κO)bis(2,2'-bipyridine-κ2N,N')copper(II) acetate–acetic acid–water (1/1/3), [Cu(C2H3O2)(C10H8N2)2](C2H3O2)·C2H4O2·3H2O or [Cu(bipy)2Ac]Ac·HAc·3H2O, are reported and compared with the previously published structure of [Cu(phen)2Ac]Ac·7H2O (phen is 1,10-phenanthroline, bipy for 2,2'-bipyridine, ac is acetate and Hac is acetic acid). The geometry around the metal centre is pentacoordinated, but highly distorted in all three cases. The coordination number and the geometric distortion are both discussed in detail, and all complexes belong to the space group Poverline{1}. The analysis of the geometric parameters and the Hirshfeld surface properties dnorm and curvedness provide information about the metal–ligand interactions in these complexes and allow comparison with similar systems. Full Article text
eta A web-based dashboard for RELION metadata visualization By journals.iucr.org Published On :: 2024-01-24 Cryo-electron microscopy (cryo-EM) has witnessed radical progress in the past decade, driven by developments in hardware and software. While current software packages include processing pipelines that simplify the image-processing workflow, they do not prioritize the in-depth analysis of crucial metadata, limiting troubleshooting for challenging data sets. The widely used RELION software package lacks a graphical native representation of the underlying metadata. Here, two web-based tools are introduced: relion_live.py, which offers real-time feedback on data collection, aiding swift decision-making during data acquisition, and relion_analyse.py, a graphical interface to represent RELION projects by plotting essential metadata including interactive data filtration and analysis. A useful script for estimating ice thickness and data quality during movie pre-processing is also presented. These tools empower researchers to analyse data efficiently and allow informed decisions during data collection and processing. Full Article text
eta Mononuclear binding and catalytic activity of europium(III) and gadolinium(III) at the active site of the model metalloenzyme phosphotriesterase By journals.iucr.org Published On :: 2024-03-21 Lanthanide ions have ideal chemical properties for catalysis, such as hard Lewis acidity, fast ligand-exchange kinetics, high coordination-number preferences and low geometric requirements for coordination. As a result, many small-molecule lanthanide catalysts have been described in the literature. Yet, despite the ability of enzymes to catalyse highly stereoselective reactions under gentle conditions, very few lanthanoenzymes have been investigated. In this work, the mononuclear binding of europium(III) and gadolinium(III) to the active site of a mutant of the model enzyme phosphotriesterase are described using X-ray crystallography at 1.78 and 1.61 Å resolution, respectively. It is also shown that despite coordinating a single non-natural metal cation, the PTE-R18 mutant is still able to maintain esterase activity. Full Article text
eta A database overview of metal-coordination distances in metalloproteins By journals.iucr.org Published On :: 2024-04-29 Metalloproteins are ubiquitous in all living organisms and take part in a very wide range of biological processes. For this reason, their experimental characterization is crucial to obtain improved knowledge of their structure and biological functions. The three-dimensional structure represents highly relevant information since it provides insight into the interaction between the metal ion(s) and the protein fold. Such interactions determine the chemical reactivity of the bound metal. The available PDB structures can contain errors due to experimental factors such as poor resolution and radiation damage. A lack of use of distance restraints during the refinement and validation process also impacts the structure quality. Here, the aim was to obtain a thorough overview of the distribution of the distances between metal ions and their donor atoms through the statistical analysis of a data set based on more than 115 000 metal-binding sites in proteins. This analysis not only produced reference data that can be used by experimentalists to support the structure-determination process, for example as refinement restraints, but also resulted in an improved insight into how protein coordination occurs for different metals and the nature of their binding interactions. In particular, the features of carboxylate coordination were inspected, which is the only type of interaction that is commonly present for nearly all metals. Full Article text
eta Time-series analysis of rhenium(I) organometallic covalent binding to a model protein for drug development By journals.iucr.org Published On :: 2024-04-19 Metal-based complexes with their unique chemical properties, including multiple oxidation states, radio-nuclear capabilities and various coordination geometries yield value as potential pharmaceuticals. Understanding the interactions between metals and biological systems will prove key for site-specific coordination of new metal-based lead compounds. This study merges the concepts of target coordination with fragment-based drug methodologies, supported by varying the anomalous scattering of rhenium along with infrared spectroscopy, and has identified rhenium metal sites bound covalently with two amino acid types within the model protein. A time-based series of lysozyme-rhenium-imidazole (HEWL-Re-Imi) crystals was analysed systematically over a span of 38 weeks. The main rhenium covalent coordination is observed at His15, Asp101 and Asp119. Weak (i.e. noncovalent) interactions are observed at other aspartic, asparagine, proline, tyrosine and tryptophan side chains. Detailed bond distance comparisons, including precision estimates, are reported, utilizing the diffraction precision index supplemented with small-molecule data from the Cambridge Structural Database. Key findings include changes in the protein structure induced at the rhenium metal binding site, not observed in similar metal-free structures. The binding sites are typically found along the solvent-channel-accessible protein surface. The three primary covalent metal binding sites are consistent throughout the time series, whereas binding to neighbouring amino acid residues changes through the time series. Co-crystallization was used, consistently yielding crystals four days after setup. After crystal formation, soaking of the compound into the crystal over 38 weeks is continued and explains these structural adjustments. It is the covalent bond stability at the three sites, their proximity to the solvent channel and the movement of residues to accommodate the metal that are important, and may prove useful for future radiopharmaceutical development including target modification. Full Article text
eta On the structure refinement of metal complexes against 3D electron diffraction data using multipolar scattering factors By journals.iucr.org Published On :: 2024-08-15 This study examines various methods for modelling the electron density and, thus, the electrostatic potential of an organometallic complex for use in crystal structure refinement against 3D electron diffraction (ED) data. It focuses on modelling the scattering factors of iron(III), considering the electron density distribution specific for coordination with organic linkers. We refined the structural model of the metal–organic complex, iron(III) acetylacetonate (FeAcAc), using both the independent atom model (IAM) and the transferable aspherical atom model (TAAM). TAAM refinement initially employed multipolar parameters from the MATTS databank for acetylacetonate, while iron was modelled with a spherical and neutral approach (TAAM ligand). Later, custom-made TAAM scattering factors for Fe—O coordination were derived from DFT calculations [TAAM-ligand-Fe(III)]. Our findings show that, in this compound, the TAAM scattering factor corresponding to Fe3+ has a lower scattering amplitude than the Fe3+ charged scattering factor described by IAM. When using scattering factors corresponding to the oxidation state of iron, IAM inaccurately represents electrostatic potential maps and overestimates the scattering potential of the iron. In addition, TAAM significantly improved the fitting of the model to the data, shown by improved R1 values, goodness-of-fit (GooF) and reduced noise in the Fourier difference map (based on the residual distribution analysis). For 3D ED, R1 values improved from 19.36% (IAM) to 17.44% (TAAM-ligand) and 17.49% (TAAM-ligand-Fe3+), and for single-crystal X-ray diffraction (SCXRD) from 3.82 to 2.03% and 1.98%, respectively. For 3D ED, the most significant R1 reductions occurred in the low-resolution region (8.65–2.00 Å), dropping from 20.19% (IAM) to 14.67% and 14.89% for TAAM-ligand and TAAM-ligand-Fe(III), respectively, with less improvement in high-resolution ranges (2.00–0.85 Å). This indicates that the major enhancements are due to better scattering modelling in low-resolution zones. Furthermore, when using TAAM instead of IAM, there was a noticeable improvement in the shape of the thermal ellipsoids, which more closely resembled those of an SCXRD-refined model. This study demonstrates the applicability of more sophisticated scattering factors to improve the refinement of metal–organic complexes against 3D ED data, suggesting the need for more accurate modelling methods and highlighting the potential of TAAM in examining the charge distribution of large molecular structures using 3D ED. Full Article text
eta CheckMyMetal (CMM): validating metal-binding sites in X-ray and cryo-EM data By journals.iucr.org Published On :: 2024-08-14 Identifying and characterizing metal-binding sites (MBS) within macromolecular structures is imperative for elucidating their biological functions. CheckMyMetal (CMM) is a web based tool that facilitates the interactive validation of MBS in structures determined through X-ray crystallography and cryo-electron microscopy (cryo-EM). Recent updates to CMM have significantly enhanced its capability to efficiently handle large datasets generated from cryo-EM structural analyses. In this study, we address various challenges inherent in validating MBS within both X-ray and cryo-EM structures. Specifically, we examine the difficulties associated with accurately identifying metals and modeling their coordination environments by considering the ongoing reproducibility challenges in structural biology and the critical importance of well annotated, high-quality experimental data. CMM employs a sophisticated framework of rules rooted in the valence bond theory for MBS validation. We explore how CMM validation parameters correlate with the resolution of experimentally derived structures of macromolecules and their complexes. Additionally, we showcase the practical utility of CMM by analyzing a representative cryo-EM structure. Through a comprehensive examination of experimental data, we demonstrate the capability of CMM to advance MBS characterization and identify potential instances of metal misassignment. Full Article text
eta Tuning structural modulation and magnetic properties in metal–organic coordination polymers [CH3NH3]CoxNi1−x(HCOO)3 By journals.iucr.org Published On :: 2024-09-24 Three solid solutions of [CH3NH3]CoxNi1−x(HCOO)3, with x = 0.25 (1), x = 0.50 (2) and x = 0.75 (3), were synthesized and their nuclear structures and magnetic properties were characterized using single-crystal neutron diffraction and magnetization measurements. At room temperature, all three compounds crystallize in the Pnma orthorhombic space group, akin to the cobalt and nickel end series members. On cooling, each compound undergoes a distinct series of structural transitions to modulated structures. Compound 1 exhibits a phase transition to a modulated structure analogous to the pure Ni compound [Cañadillas-Delgado, L., Mazzuca, L., Fabelo, O., Rodríguez-Carvajal, J. & Petricek, V. (2020). Inorg. Chem. 59, 17896–17905], whereas compound 3 maintains the behaviour observed in the pure Co compound reported previously [Canadillas-Delgado, L., Mazzuca, L., Fabelo, O., Rodriguez-Velamazan, J. A. & Rodriguez-Carvajal, J. (2019). IUCrJ, 6, 105–115], although in both cases the temperatures at which the phase transitions occur differ slightly from the pure phases. Monochromatic neutron diffraction measurements showed that the structural evolution of 2 diverges from that of either parent compound, with competing hydrogen bond interactions that drive the modulation throughout the series, producing a unique sequence of phases. It involves two modulated phases below 96 (3) and 59 (3) K, with different q vectors, similar to the pure Co compound (with modulated phases below 128 and 96 K); however, it maintains the modulated phase below magnetic order [at 22.5 (7) K], resembling the pure Ni compound (which presents magnetic order below 34 K), resulting in an improper modulated magnetic structure. Despite these large-scale structural changes, magnetometry data reveal that the bulk magnetic properties of these solid solutions form a linear continuum between the end members. Notably, doping of the metal site in these solid solutions allows for tuning of bulk magnetic properties, including magnetic ordering temperature, transition temperatures and the nature of nuclear phase transitions, through adjustment of metal ratios. Full Article text
eta Elastic and inelastic strain in submicron-thick ZnO epilayers grown on r-sapphire substrates by metal–organic vapour phase deposition By journals.iucr.org Published On :: 2024-02-13 A significant part of the present and future of optoelectronic devices lies on thin multilayer heterostructures. Their optical properties depend strongly on strain, being essential to the knowledge of the stress level to optimize the growth process. Here the structural and microstructural characteristics of sub-micron a-ZnO epilayers (12 to 770 nm) grown on r-sapphire by metal–organic chemical vapour deposition are studied. Morphological and structural studies have been made using scanning electron microscopy and high-resolution X-ray diffraction. Plastic unit-cell distortion and corresponding strain have been determined as a function of film thickness. A critical thickness has been observed as separating the non-elastic/elastic states with an experimental value of 150–200 nm. This behaviour has been confirmed from ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy measurements. An equation that gives the balance of strains is proposed as an interesting method to experimentally determine this critical thickness. It is concluded that in the thinnest films an elongation of the Zn—O bond takes place and that the plastic strained ZnO films relax through nucleation of misfit dislocations, which is a consequence of three-dimensional surface morphology. Full Article text
eta Synthesis and crystal structure of diisothiocyanatotetrakis(4-methylpyridine N-oxide)cobalt(II) and diisothiocyanatotris(4-methylpyridine N-oxide)cobalt(II) showing two different metal coor By journals.iucr.org Published On :: 2024-01-26 The reaction of Co(NCS)2 with 4-methylpyridine N-oxide (C6H7NO) leads to the formation of two compounds, namely, tetrakis(4-methylpyridine N-oxide-κO)bis(thiocyanato-κN)cobalt(II), [Co(NCS)2(C6H7NO)4] (1), and tris(4-methylpyridine N-oxide-κO)bis(thiocyanato-κN)cobalt(II), [Co(NCS)2(C6H7NO)3] (2). The asymmetric unit of 1 consists of one CoII cation located on a centre of inversion, as well as one thiocyanate anion and two 4-methylpyridine N-oxide coligands in general positions. The CoII cations are octahedrally coordinated by two terminal N-bonding thiocyanate anions in trans positions and four 4-methylpyridine N-oxide ligands. In the extended structure, these complexes are linked by C—H⋯O and C—H⋯S interactions. In compound 2, two crystallographically independent complexes are present, which occupy general positions. In each of these complexes, the CoII cations are coordinated in a trigonal–bipyramidal manner by two terminal N-bonding thiocyanate anions in axial positions and by three 4-methylpyridine N-oxide ligands in equatorial positions. In the crystal, these complex molecules are linked by C—H⋯S interactions. For compound 2, a nonmerohedral twin refinement was performed. Powder X-ray diffraction (PXRD) reveals that 2 was nearly obtained as a pure phase, which is not possible for compound 1. Differential thermoanalysis and thermogravimetry data (DTA–TG) show that compound 2 start to decompose at about 518 K. Full Article text
eta Structural characterization of a new samarium–sodium heterometallic coordination polymer By journals.iucr.org Published On :: 2024-02-06 Lanthanide-containing materials are of interest in the field of crystal engineering because of their unique properties and distinct structure types. In this context, a new samarium–sodium heterometallic coordination polymer, poly[tetrakis(μ2-2-formyl-6-methoxyphenolato)samarium(III)sodium(I)], {[SmNa(C8H7O3)4]·solvent}n (Sm-1), was synthesized and crystallized via slow evaporation from a mixture of ethanol and acetonitrile. The compound features alternating SmIII and NaI ions, which are linked by ortho-vanillin (o-vanillin) ligands to form a mono-periodic chain-like coordination polymer. The chains propagate along the [001] direction. Residual electron density of disordered solvent molecules in the void space could not be reasonably modeled, thus the SQUEEZE function was applied. The structural, vibrational, and optical properties are reported. Full Article text
eta Synthesis, crystal structure and Hirshfeld surface analysis of N-(6-acetyl-1-nitronaphthalen-2-yl)acetamide By journals.iucr.org Published On :: 2024-03-06 The title compound, C14H12N2O4, was obtained from 2-acetyl-6-aminonaphthalene through two-step reactions of acetylation and nitration. The molecule comprises the naphthalene ring system consisting of functional systems bearing a acetyl group (C-2), a nitro group (C-5), and an acetylamino group (C-6). In the crystal, the molecules are assembled into two-dimensional sheet-like structures by intermolecular N—H⋯O and C—H⋯O hydrogen-bonding interactions. Hirshfeld surface analysis illustrates that the most important contributions to the crystal packing are from O⋯H/H⋯O (43.7%), H⋯H (31.0%), and C⋯H/H⋯C (8.5%) contacts. Full Article text
eta Synthesis and crystal structure of N-phenyl-2-(phenylsulfanyl)acetamide By journals.iucr.org Published On :: 2024-03-26 N-Phenyl-2-(phenylsulfanyl)acetamide, C14H13NOS, was synthesized and structurally characterized. In the crystal, N—H⋯O hydrogen bonding leads to the formation of chains of molecules along the [100] direction. The chains are linked by C—H⋯π interactions, forming a three-dimensional network. The crystal studied was twinned by a twofold rotation around [100]. Full Article text
eta Crystal structure and Hirshfeld surface analysis of ethyl 2-(7-chloro-3-methyl-2-oxo-1,2-dihydroquinoxalin-1-yl)acetate By journals.iucr.org Published On :: 2024-03-26 The quinoxaline moiety in the title molecule, C13H13ClN2O3, is almost planar (r.m.s. deviation of the fitted atoms = 0.033 Å). In the crystal, C—H⋯O hydrogen bonds plus slipped π-stacking and C—H⋯π(ring) interactions generate chains of molecules extending along the b-axis direction. The chains are connected by additional C—H⋯O hydrogen bonds. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (37.6%), H⋯O/O⋯H (22.7%) and H⋯Cl/Cl⋯H (13.1%) interactions. Full Article text
eta 2-Cyano-2-isonitrosoacetamide–3,4-dimethylpyrazole (1/1): a co-crystal of two molecules with agrochemical activities By journals.iucr.org Published On :: 2024-04-04 In the structure of the title co-crystal, C3H3N3O2·C5H8N2, the components are linked by a set of directional O—H⋯N, N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds to yield a two-dimensional mono-periodic arrangement. The structure propagates in the third dimension by extensive π–π stacking interactions of nearly parallel molecules of the two components, following an alternating sequence. The primary structure-defining interaction is very strong oxime-OH donor to pyrazole-N acceptor hydrogen bond [O⋯N = 2.587 (2) Å], while the significance of weaker hydrogen bonds and π–π stacking interactions is comparable. The distinct structural roles of different kinds of interactions agree with the results of a Hirshfeld surface analysis and calculated interaction energies. The title compound provides insights into co-crystals of active agrochemical molecules and features the rational integration in one structure of a fungicide, C3H3N3O2, and a second active component, C5H8N2, known for alleviation the toxic effects of fungicides on plants. The material appears to be well suited for practical uses, being non-volatile, air-stable, water-soluble, but neither hygroscopic nor efflorescent. Full Article text
eta Crystal structure of bis{2-[5-(3,4,5-trimethoxyphenyl)-4H-1,2,4-triazol-3-yl]pyridine}palladium(II) bis(trifluoroacetate) trifluoroacetic acid disolvate By journals.iucr.org Published On :: 2024-05-03 The new palladium(II) complex, [Pd(C16H16N4O3)2](CF3COO)2·2CF3COOH, crystallizes in the triclinic space group Poverline{1} with the asymmetric unit containing half the cation (PdII site symmetry Ci), one trifluoroactetate anion and one co-crystallized trifluoroacetic acid molecule. Two neutral chelating 2-[5-(3,4,5-trimethoxyphenyl)-4H-1,2,4-triazol-3-yl]pyridine ligands coordinate to the PdII ion through the triazole-N and pyridine-N atoms in a distorted trans-PdN4 square-planar configuration [Pd—N 1.991 (2), 2.037 (2) Å; cis N—Pd—N 79.65 (8), 100.35 (8)°]. The complex cation is quite planar, except for the methoxo groups (δ = 0.117 Å for one of the C atoms). The planar configuration is supported by two intramolecular C—H⋯N hydrogen bonds. In the crystal, the π–π-stacked cations are arranged in sheets parallel to the ab plane that are flanked on both sides by the trifluoroacetic acid–trifluoroacetate anion pairs. Apart from classical N/O—H⋯O hydrogen-bonding interactions, weak C—H⋯F/N/O contacts consolidate the three-dimensional architecture. Both trifluoroacetic moieties were found to be disordered over two resolvable positions with a refined occupancy ratio of 0.587 (1):0.413 (17) and 0.530 (6):0.470 (6) for the protonated and deprotonated forms, respectively. Full Article text
eta Ethyl 2-[(2-oxo-2H-chromen-6-yl)oxy]acetate By journals.iucr.org Published On :: 2024-05-31 Ethyl 2-[(2-oxo-2H-chromen-6-yl)oxy]acetate, C13H12O5, a member of the pharmacologically important class of coumarins, crystallizes in the monoclinic C2/c space group in the form of sheets, within which molecules are related by inversion centers and 21 axes. Multiple C—H⋯O weak hydrogen-bonding interactions reinforce this pattern. The planes of these sheets are oriented in the approximate direction of the ac face diagonal. Intersheet interactions are a combination of coumarin system π–π stacking and additional C—H⋯O weak hydrogen bonds between ethyl acetoxy groups. Full Article text
eta Synthesis and crystal structure of bis(2-aminobenzimidazolium) catena-[metavanadate(V)] By journals.iucr.org Published On :: 2024-06-18 The structure of polymeric catena-poly[2-aminobenzimidazolium [[dioxidovanadium(V)]-μ-oxido]], {(C7H8N3)2[V2O6]}n, has monoclinic symmetry. The title compound is of interest with respect to anticancer activity. In the crystal structure, infinite linear zigzag vanadate (V2O6)2− chains, constructed from corner-sharing VO4 tetrahedra and that run parallel to the a axis, are present. Two different protonated 2-aminobenzimidazole molecules are located between the (V2O6)2– chains and form classical N—H⋯O hydrogen bonds with the vanadate oxygen atoms, which contribute to the cohesion of the structure. Full Article text
eta Two chromium(II) acetate complexes with N-heterocyclic carbene (NHC) coligands By journals.iucr.org Published On :: 2024-06-28 Tetrakis(μ-acetato-κ2O:O')bis{[1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene-κC2]chromium(II)} tetrahydrofuran disolvate, [Cr2(C2H3O2)4(C27H36N4)2]·2C4H8O or [Cr2(OAc)4(IDipp)2]·2C4H8O (1), and tetrakis(μ-acetato-κ2O:O')bis{[1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene-κC2]chromium(II)}, {Cr2(C2H3O2)4(C21H24N2)2] or [Cr2(OAc)4(IMes)2] (2), were synthesized from anhydrous chromium(II) acetate [Cr2(OAc)4] and the corresponding NHC (NHC = N-heterocyclic carbene) in toluene as solvent. Both complexes crystallize in the triclinic system, space group Poverline{1}. The molecular structures consist of Cr2(OAc)4 paddle-wheels that carry two terminal NHC ligands. This leads to a square-pyramidal coordination of the chromium atoms. Full Article text
eta Crystal structure of catena-poly[[methanoldioxidouranium(VI)]-μ-2-[5-(2-oxidophenyl)-1H-1,2,4-triazol-3-yl]acetato-κ2O:O'] By journals.iucr.org Published On :: 2024-07-12 In the title complex, [U(C10H7N3O3)O2(CH3OH)]n, the UVI cation has a typical pentagonal–bipyramidal environment with the equatorial plane defined by one N and two O atoms of one doubly deprotonated 2-[5-(2-hydroxyphenyl)-1H-1,2,4-triazol-3-yl]acetic acid ligand, a carboxylate O atom of the symmetry-related ligand and the O atom of the methanol molecule [U—N/Oeq 2.256 (4)–2.504 (5) Å]. The axial positions are occupied by two oxide O atoms. The equatorial atoms are almost coplanar, with the largest deviation from the mean plane being 0.121 Å for one of the O atoms. The benzene and triazole rings of the tetradentate chelating–bridging ligand are twisted by approximately 21.6 (2)° with respect to each other. The carboxylate group of the ligand bridges two uranyl cations, forming a neutral zigzag chain reinforced by a strong O—H⋯O hydrogen bond. In the crystal, adjacent chains are linked into two-dimensional sheets parallel to the ac plane by C/N—H⋯N/O hydrogen bonding and π–π interactions. Further weak C—H⋯O contacts consolidate the three-dimensional supramolecular architecture. In the solid state, the compound shows a broad medium intensity LMCT transition centred around 463 nm, which is responsible for its red colour. Full Article text
eta Pyrazine-bridged polymetallic copper–iridium clusters By journals.iucr.org Published On :: 2024-07-27 Single crystals of the molecular compound, {Cu20Ir6Cl8(C21H24N2)6(C4H4N2)3]·3.18CH3OH or [({Cu10Ir3}Cl4(IMes)3(pyrazine))2(pyrazine)]·3.18CH3OH [where IMes is 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene], with a unique heterometallic cluster have been prepared and the structure revealed using single-crystal X-ray diffraction. The molecule is centrosymmetric with two {Cu10Ir3} cores bridged by a pyrazine ligand. The polymetallic cluster contains three stabilizing N-heterocyclic carbenes, four Cl ligands, and a non-bridging pyrazine ligand. Notably, the Cu—Ir core is arranged in an unusual shape containing 13 vertices, 22 faces, and 32 sides. The atoms within the tridecametallic cluster are arranged in four planes, with 2, 4, 4, 3 metals in each plane. Ir atoms are present in alternate planes with an Ir atom featuring in the peripheral bimetallic plane, and two Ir atoms featuring on opposite sides of the non-adjacent tetrametallic plane. The crystal contains two disordered methanol solvent molecules with an additional region of non-modelled electron density corrected for using the SQUEEZE routine in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unmodelled methanol solvent molecule(s). Full Article text
eta Synthesis, crystal structure and Hirshfeld surface of ethyl 2-[2-(methylsulfanyl)-5-oxo-4,4-diphenyl-4,5-dihydro-1H-imidazol-1-yl]acetate (thiophenytoin derivative) By journals.iucr.org Published On :: 2024-08-09 The dihydroimidazole ring in the title molecule, C20H20N2O3S, is slightly distorted and the lone pair on the tri-coordinate nitrogen atom is involved in intra-ring π bonding. The methylsulfanyl substituent lies nearly in the plane of the five-membered ring while the ester substituent is rotated well out of that plane. In the crystal, C—H⋯O hydrogen bonds form inversion dimers, which are connected along the a- and c-axis directions by additional C—H⋯O hydrogen bonds, forming layers parallel to the ac plane. The major contributors to the Hirshfeld surface are C⋯H/H⋯C, O⋯H/H⋯O and S⋯H/H⋯S contacts at 20.5%, 14.7% and 4.9%, respectively. Full Article text
eta Synthesis, crystal structure and Hirshfeld surface analysis of [1-(4-bromophenyl)-1H-1,2,3-triazol-4-yl]methyl 2-(4-nitrophenoxy)acetate By journals.iucr.org Published On :: 2024-07-31 The title compound, C17H13BrN4O5, was synthesized by a Cu2Br2-catalysed Meldal–Sharpless reaction between 4-nitrophenoxyacetic acid propargyl ether and para-bromophenylazide, and characterized by X-ray structure determination and 1H NMR spectroscopy. The molecules, with a near-perpendicular orientation of the bromophenyl-triazole and nitrophenoxyacetate fragments, are connected into a three-dimensional network by intermolecular C—H⋯O and C—H⋯N hydrogen bonds (confirmed by Hirshfeld surface analysis), π–π and Br–π interactions. Full Article text
eta Synthesis, crystal structure and Hirshfeld surface analysis of a new copper(II) complex based on diethyl 2,2'-(4H-1,2,4-triazole-3,5-diyl)diacetate By journals.iucr.org Published On :: 2024-08-30 The title compound, bis[μ-2,2'-(4H-1,2,4-triazole-3,5-diyl)diacetato]bis[diaquacopper(II)] dihydrate, [Cu2(C6H5N3O4)2(H2O)4]·2H2O, is a dinuclear octahedral CuII triazole-based complex. The central copper atoms are hexa-coordinated by two nitrogen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxylate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water molecules. Two additional solvent water molecules are linked to the title molecule by O—H⋯N and O⋯H—O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supramolecular chains running along the a-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H⋯O/O⋯H (53.5%), H⋯H (28.1%), O⋯O (6.3%) and H⋯C/C⋯H (6.2%) interactions. The crystal studied was twinned by a twofold rotation around [100]. Full Article text
eta Three-dimensional alkaline earth metal–organic framework poly[[μ-aqua-aquabis(μ3-carbamoylcyanonitrosomethanido)barium] monohydrate] and its thermal decomposition By journals.iucr.org Published On :: 2024-08-30 In the structure of the title salt, {[Ba(μ3-C3H2N3O2)2(μ-H2O)(H2O)]·H2O}n, the barium ion and all three oxygen atoms of the water molecules reside on a mirror plane. The hydrogen atoms of the bridging water and the solvate water molecules are arranged across a mirror plane whereas all atoms of the monodentate aqua ligand are situated on this mirror plane. The distorted ninefold coordination of the Ba ions is completed with four nitroso-, two carbonyl- and three aqua-O atoms at the distances of 2.763 (3)–2.961 (4) Å and it is best described as tricapped trigonal prism. The three-dimensional framework structure is formed by face-sharing of the trigonal prisms, via μ-nitroso- and μ-aqua-O atoms, and also by the bridging coordination of the anions via carbonyl-O atoms occupying two out of the three cap positions. The solvate water molecules populate the crystal channels and facilitate a set of four directional hydrogen bonds. The principal Ba–carbamoylcyanonitrosomethanido linkage reveals a rare example of the inherently polar binodal six- and three-coordinated bipartite topology (three-letter notation sit). It suggests that small resonance-stabilized cyanonitroso anions can be utilized as bridging ligands for the supramolecular synthesis of MOF solids. Such an outcome may be anticipated for a broader range of hard Lewis acidic alkaline earth metal ions, which perfectly match the coordination preferences of highly nucleophilic nitroso-O atoms. Thermal analysis reveals two-stage dehydration of the title compound (383 and 473 K) followed by decomposition with release of CO2, HCN and H2O at 558 K. Full Article text
eta Synthesis, crystal structure and Hirshfeld surface analysis of 2-{4-[(2-chlorophenyl)methyl]-3-methyl-6-oxopyridazin-1-yl}-N-phenylacetamide By journals.iucr.org Published On :: 2024-10-31 In the title molecule, C20H18ClN3O2, the 2-chlorophenyl group is disordered to a small extent [occupancies 0.875 (2)/0.125 (2)]. The phenylacetamide moiety is nearly planar due to a weak, intramolecular C—H⋯O hydrogen bond. In the crystal, N—H⋯O hydrogen bonds and π-stacking interactions between pyridazine and phenyl rings form helical chains of molecules in the b-axis direction, which are linked by C—H⋯O hydrogen bonds and C—H⋯π(ring) interactions. A Hirshfeld surface analysis was performed, which showed that H⋯H, C⋯H/H⋯C and O⋯H/H⋯O interactions to dominate the intermolecular contacts in the crystal. Full Article text
eta POMFinder: identifying polyoxometallate cluster structures from pair distribution function data using explainable machine learning By journals.iucr.org Published On :: 2024-02-01 Characterization of a material structure with pair distribution function (PDF) analysis typically involves refining a structure model against an experimental data set, but finding or constructing a suitable atomic model for PDF modelling can be an extremely labour-intensive task, requiring carefully browsing through large numbers of possible models. Presented here is POMFinder, a machine learning (ML) classifier that rapidly screens a database of structures, here polyoxometallate (POM) clusters, to identify candidate structures for PDF data modelling. The approach is shown to identify suitable POMs from experimental data, including in situ data collected with fast acquisition times. This automated approach has significant potential for identifying suitable models for structure refinement to extract quantitative structural parameters in materials chemistry research. POMFinder is open source and user friendly, making it accessible to those without prior ML knowledge. It is also demonstrated that POMFinder offers a promising modelling framework for combined modelling of multiple scattering techniques. Full Article text
eta X-ray standing wave characterization of the strong metal–support interaction in Co/TiOx model catalysts By journals.iucr.org Published On :: 2024-03-31 The strong metal–support interaction (SMSI) is a phenomenon observed in supported metal catalyst systems in which reducible metal oxide supports can form overlayers over the surface of active metal nanoparticles (NPs) under a hydrogen (H2) environment at elevated temperatures. SMSI has been shown to affect catalyst performance in many reactions by changing the type and number of active sites on the catalyst surface. Laboratory methods for the analysis of SMSI at the nanoparticle-ensemble level are lacking and mostly based on indirect evidence, such as gas chemisorption. Here, we demonstrate the possibility to detect and characterize SMSIs in Co/TiOx model catalysts using the laboratory X-ray standing wave (XSW) technique for a large ensemble of NPs at the bulk scale. We designed a thermally stable MoNx/SiNx periodic multilayer to retain XSW generation after reduction with H2 gas at 600°C. The model catalyst system was synthesized here by deposition of a thin TiOx layer on top of the periodic multilayer, followed by Co NP deposition via spare ablation. A partial encapsulation of Co NPs by TiOx was identified by analyzing the change in Ti atomic distribution. This novel methodological approach can be extended to observe surface restructuring of model catalysts in situ at high temperature (up to 1000°C) and pressure (≤3 mbar), and can also be relevant for fundamental studies in the thermal stability of membranes, as well as metallurgy. Full Article text
eta Synthesis and in-depth structure determination of a novel metastable high-pressure CrTe3 phase By journals.iucr.org Published On :: 2024-05-24 This study reports the synthesis and crystal structure determination of a novel CrTe3 phase using various experimental and theoretical methods. The average stoichiometry and local phase separation of this quenched high-pressure phase were characterized by ex situ synchrotron powder X-ray diffraction and total scattering. Several structural models were obtained using simulated annealing, but all suffered from an imperfect Rietveld refinement, especially at higher diffraction angles. Finally, a novel stoichiometrically correct crystal structure model was proposed on the basis of electron diffraction data and refined against powder diffraction data using the Rietveld method. Scanning electron microscopy–energy-dispersive X-ray spectrometry (EDX) measurements verified the targeted 1:3 (Cr:Te) average stoichiometry for the starting compound and for the quenched high-pressure phase within experimental errors. Scanning transmission electron microscopy (STEM)–EDX was used to examine minute variations of the Cr-to-Te ratio at the nanoscale. Precession electron diffraction (PED) experiments were applied for the nanoscale structure analysis of the quenched high-pressure phase. The proposed monoclinic model from PED experiments provided an improved fit to the X-ray patterns, especially after introducing atomic anisotropic displacement parameters and partial occupancy of Cr atoms. Atomic resolution STEM and simulations were conducted to identify variations in the Cr-atom site-occupancy factor. No significant variations were observed experimentally for several zone axes. The magnetic properties of the novel CrTe3 phase were investigated through temperature- and field-dependent magnetization measurements. In order to understand these properties, auxiliary theoretical investigations have been performed by first-principles electronic structure calculations and Monte Carlo simulations. The obtained results allow the observed magnetization behavior to be interpreted as the consequence of competition between the applied magnetic field and the Cr–Cr exchange interactions, leading to a decrease of the magnetization towards T = 0 K typical for antiferromagnetic systems, as well as a field-induced enhanced magnetization around the critical temperature due to the high magnetic susceptibility in this region. Full Article text
eta Low-dose electron microscopy imaging for beam-sensitive metal–organic frameworks By journals.iucr.org Published On :: 2024-09-05 Metal–organic frameworks (MOFs) have garnered significant attention in recent years owing to their exceptional properties. Understanding the intricate relationship between the structure of a material and its properties is crucial for guiding the synthesis and application of these materials. (Scanning) Transmission electron microscopy (S)TEM imaging stands out as a powerful tool for structural characterization at the nanoscale, capable of detailing both periodic and aperiodic local structures. However, the high electron-beam sensitivity of MOFs presents substantial challenges in their structural characterization using (S)TEM. This paper summarizes the latest advancements in low-dose high-resolution (S)TEM imaging technology and its application in MOF material characterization. It covers aspects such as framework structure, defects, and surface and interface analysis, along with the distribution of guest molecules within MOFs. This review also discusses emerging technologies like electron ptychography and outlines several prospective research directions in this field. Full Article text
eta ADIB safely tests fractional Sukuks offering for retail investors By thepaypers.com Published On :: Mon, 11 Nov 2024 10:59:00 +0100 Abu Dhabi Islamic Bank (ADIB) has announced that... Full Article
eta New Book Details Full History Of Black Baseball Players’ Fight For Integration By www.scpr.org Published On :: Tue, 06 Jul 2021 09:06:25 -0700 Copy of the book “Beyond Baseball’s Color Barrier: The Story of African Americans in Major League Baseball, Past, Present, and Future” (Rowman & Littlefield, May 2021) AirTalkMost of us are familiar with the story of Jackie Robinson, the first Black player to play baseball in the Major Leagues, and while Jackie’s story is arguably the biggest chapter in the story of how baseball was integrated, there’s plenty more to the story that happened both before and after Jackie broke into the Majors. Author, sports historian and Santa Barbara City College Director of Athletics Rocco Constantino dives into this rich history in his new book “Beyond Baseball’s Color Barrier: The Story of African Americans in Major League Baseball, Past, Present, and Future” where he explores the contributions of major figures like Hank Aaron, Willie Mays and Satchel Paige as well as the lesser known ones of players like Vida Blue, Mudcat Grant and Dwight Gooden. Today on AirTalk, Constantino joins Larry Mantle to explore the history of Black players in baseball, their fight for recognition and integration into the Major Leagues and the issues of race that persisted well beyond Jackie Robinson breaking baseball’s color barrier. Guest: Rocco Constantino, author of “Beyond Baseball’s Color Barrier: The Story of African Americans in Major League Baseball, Past, Present, and Future” (Rowman & Littlefield, May 2021); he is a sports historian and the director of athletics at Santa Barbara City College This content is from Southern California Public Radio. View the original story at SCPR.org. Full Article
eta Arizona Republicans Strip Some Election Power From Democratic Secretary Of State By www.scpr.org Published On :: Wed, 30 Jun 2021 19:00:09 -0700 "This is a petty, partisan power grab that is absolutely retaliation towards my office," Arizona Democratic Secretary of State Katie Hobbs says of the new law.; Credit: Ross D. Franklin/AP Ben Giles | NPRArizona Republicans have stripped the secretary of state's office — currently held by a Democrat — of the right to defend the state's election laws in court, or choose not to, a change enacted as part of Arizona's newly signed budget. The spending blueprint that Gov. Doug Ducey signed into law Wednesday declares that the attorney general — currently a position occupied by Republican Mark Brnovich — has sole authority over election-related litigation. If the secretary of state and attorney general were to disagree over a legal strategy when Arizona election laws are challenged, the new law states that "the authority of the attorney general to defend the law is paramount." Republicans also adopted language stating it's their intent for the law to apply through Jan. 2, 2023, coinciding with the end of Democrat Katie Hobbs' term as secretary of state. Hobbs, the top election official in Arizona who's now running for governor, says her lawyers are looking at whether this change violates the Arizona Constitution. "This is a petty, partisan power grab that is absolutely retaliation towards my office," Hobbs said. "It's clear by the fact that it ends when my term ends. ... It is at best legally questionable, but at worst, likely unconstitutional." Republicans have generally cast the law as a cost-saving measure, citing Hobbs and Brnovich's frequent disagreements over how to defend state election laws that have been challenged in court. In 2020, Hobbs filed complaints with the state bar against Brnovich and other lawyers in his office. Other election provisions in the budget The budget includes a number of other election provisions, and it comes weeks after Republicans enacted new restrictions on early voting in the state, and as a controversial review of 2020 election results in Maricopa County continues. Here are some of the other election-related measures in the budget: New laws could soon require watermarks, QR codes and other security measures to be printed on ballots. There's a new mandate to inspect state and county voter registration databases and create a report on voters who cast federal-only ballots — an option available to Arizonans who don't show proof of citizenship to register to vote in the state, but are still allowed to register under federal law. And a new task force would investigate alleged social media bias as an unreported in-kind political contribution. The ballot security measures, though not mandated by law in the budget, have the potential to be the most cumbersome and costly requirement for county election officials to implement. The budget amendment provides a list of 10 "ballot fraud countermeasures" for counties to choose from — features like holographic foil, background designs similar to those found on banknotes and ultraviolet or infrared ink. If mandated, counties would have to implement any combination of at least three features from the list on their ballots. The budget provides $12 million to pay for those features, to be split among Arizona's 15 counties. "By everyone's admission, there is only one company that can do any of this," said Jennifer Marson, executive director of the Arizona Association of Counties. "And so now, we can't have a competitive bid process or a traditional procurement process at the county or state level to use these countermeasures because we're locked into one company." That company is Authentix, a Texas-based firm that provided Republican Rep. Mark Finchem with a sample ballot that included watermarks, QR codes and other security measures. Finchem had the sample ballot on display at the Capitol in March. According to the Yellow Sheet Report, it could be five times more expensive to print ballots with those security measures as it is to print paper ballots currently in use. Marson said Finchem has acknowledged the security levels required of companies in the budget amendment could only be met by Authentix, and has vowed to mandate the ballot security measures in the "very near future." Finchem defended the company in a brief email. He wrote that Authentix "offers these countermeasures to governments around the world for document and tax stamp security." As the budget was being considered, Democrats like Sen. Tony Navarrete said the amendment is part of a broad effort to solidify conspiracy theories of election fraud. "It's important for us to make sure we vote down conspiracy-laced amendments that are going to hurt the integrity of our election system in the state of Arizona and encourage other states to have these bad copycat laws spread like wildfire," he said. Copyright 2021 KJZZ. To see more, visit KJZZ. This content is from Southern California Public Radio. View the original story at SCPR.org. Full Article
eta Testing Finds 'Positive' Results for Base Metal Recoveries in Spain By www.streetwisereports.com Published On :: Tue, 05 Nov 2024 00:00:00 PST Emerita Resources Corp. (EMO:TSX.V; EMOTF:OTCQB; LLJA:FSE) announces results from a metallurgical testing program at its wholly-owned Iberian Belt West (IBW) project in Spain. Read why one expert says the company is in "the right place to be." Full Article EMO:TSX.V; EMOTF:OTCQB; LLJA:FSE
eta Metals Co. Expands Into Geological Hydrogen Sector With Department of Energy Grant By www.streetwisereports.com Published On :: Tue, 05 Nov 2024 00:00:00 PST This Buy-rated Canadian explorer-developer is working to achieve first mover status in this emerging clean energy space. Find out what all it has done and is doing. Full Article GCX:TSX.V; GCXXF:OTCQB
eta Study identifies main culprit behind lithium metal battery failure By news.science360.gov Published On :: 2019-08-26T07:00:00Z Full Text:A National Science Foundation-funded research has discovered the root cause of why lithium metal batteries fail -- bits of lithium metal deposits break off from the surface of the anode during discharging and are trapped as "dead" or inactive lithium that the battery can no longer access. The discovery challenges the conventional belief that lithium metal batteries fail because of the growth of a layer, called the solid electrolyte interphase (SEI), between the lithium anode and the electrolyte. The researchers made their discovery by developing a technique to measure the amounts of inactive lithium species on the anode -- a first in the field of battery research -- and studying their micro- and nanostructures. The findings could pave the way for bringing rechargeable lithium metal batteries from the lab to the market.Image credit: University of California - San Diego Full Article
eta Metals Co. Expands Into Geological Hydrogen Sector With Department of Energy Grant By www.streetwisereports.com Published On :: Tue, 05 Nov 2024 00:00:00 PST This Buy-rated Canadian explorer-developer is working to achieve first mover status in this emerging clean energy space. Find out what all it has done and is doing. Full Article GCX:TSX.V; GCXXF:OTCQB
eta Fruits and Vegetables Yield Less Vitamin A Than Previously Thought - Upper Limit Set for Daily Intake of Vitamin A and Nine Other Nutrients By Published On :: Tue, 09 Jan 2001 06:00:00 GMT Darkly colored, carotene-rich fruits and vegetables -- such as carrots, sweet potatoes, and broccoli -- provide the body with half as much vitamin A as previously thought. Full Article
eta Societal and Technical Challenges Posed by Nuclear Waste Call for Attention by World Leaders By Published On :: Wed, 06 Jun 2001 05:00:00 GMT Focused attention by world leaders is needed to address the substantial challenges posed by disposal of spent nuclear fuel from reactors and high-level radioactive waste from processing such fuel for military or energy purposes. Full Article
eta New Dietary Guidelines Issued for Cats and Dogs By Published On :: Mon, 08 Sep 2003 05:00:00 GMT One out of every four dogs and cats in the western world is now obese. Like humans, dogs and cats that are obese run a higher risk of developing diabetes, heart disease, or other health problems. Full Article
eta Report Sets Dietary Intake Levels for Water, Salt, and Potassium To Maintain Health and Reduce Chronic Disease Risk By Published On :: Wed, 11 Feb 2004 06:00:00 GMT The vast majority of healthy people adequately meet their daily hydration needs by letting thirst be their guide, says the newest report on nutrient recommendations from the Institute of Medicine of the National Academies. Full Article
eta IOM Report Sets New Dietary Intake Levels for Calcium and Vitamin D To Maintain Health and Avoid Risks Associated With Excess By Published On :: Tue, 30 Nov 2010 06:00:00 GMT Most Americans and Canadians up to age 70 need no more than 600 international units (IUs) of vitamin D per day to maintain health, and those 71 and older may need as much as 800 IUs, says a new report from the Institute of Medicine. Full Article
eta IOM Report Details Strategy for Monitoring Safety of Childhood Immunization Schedule By Published On :: Wed, 16 Jan 2013 06:00:00 GMT A review of the available evidence underscores the safety of the federal childhood immunization schedule, says a new report from the Institute of Medicine. Full Article